The report is about construction work on Indian reservations which have been found to be having oils reserves. California Indian council is however against the idea and issues to the government, a statement with conditions that further exploration will only continue if the state will agree to approve and offer bilingual education to people living in this area, who are the Native American Indians.
It is against the government to forcefully evict these people since they have ownership rights, while at the same time the government is divided about the issue of offering bilingual education since it fears this could spark pressure from other communities who may demand the same.
Given the budget constraints that will come with this, the government must come out strongly to balance between its interests and that of the Native Americans inhabiting this area. Brown should therefore organize talks with the Native Americans to solve the issue amicably.
Information Relevant for Talks
The following information should be well tackled in the talk, The policies to be adopted for mutual benefit, how the oil project will benefit the Native Americans particularly those who own the lands, steps the government will take to ensure no private land is lost without compensation, how to address the bilingual education demand raised by the California Indian council, what might happen if the anticipated oil turns out not to be as much as expected and the budgetary implications that will follow suit. The government should also ensure it comes up with mechanisms to ensure what is agreed upon becomes biding.
Summary of the Facts Presented
The total population of Americans Indians combined with Alaska Natives of various races amount to 4.8 million. North America region only has a population of over 31 million. The language commonly spoken by the Americans living in the north have greatly changed and very few people still speak the native language, these changes have made the language to reveal not only that of the indigenous people but also that of European colonization too.
The languages that remain widely spoken in North America are thus; English, French, Spanish and other Creole languages. In California State, the most commonly spoken languages, in addition to the above mentioned, are; Chimeriko, Salinan, Esselen, Persian, Tagalong, Washo, Karuk, German, Japanese, Vietnamese, American and many others (Poul 36).
Bilingual education is the aspect of teaching learners the educational content in different languages that is, two different languages. Preposition 227 passed in 1998 on June 2nd, ended bilingual education. There are only some little exceptions which again have been replaced by Structured English raptness. Only English Proficient students were to be educated in a one year span.
Analysis of the Problem
The major problem faced by Brown is how to provide bilingual education without necessarily contravening the law which outlawed and put to an end bilingual education. Since this is the only way to ensure the California Indian councils are satisfied and the exploration continues, brown has no choice but to offer what the council demands to get access to what he wants.
He is also faced with a challenge of ensuring the minority tribes understand the reasons for his actions and why this facility will only be available for the Native American Indians.
Policies to be adopted for the Arguments
Since there is right to education for everyone, be it an English learner or not, there should be no form of discrimination. The only way to do this is to ensure that those who do not understand English are taught in a way that they can also cope up with the rest, this can only be provided through bilingual education.
Going by the statistics, there are over 5.5 millions English learners in the United States public schools, and this number has been continually growing. By eliminating bilingual education we will be cutting off the major student population (Bruce 252). Therefore, we must find a means of incorporating these groups and give them the rights they deserve.
Brown should support bilingual education by using principles which underlie the general language acquisition. Some of the principles that will assist him include; a comprehensive input assist in acquiring a second language-this comprehensive input must be the native language, background knowledge usually makes a second language more comprehensible, research has proven that; development of the first language possesses cognitive and practical advantages (Keiko & Monica 176). The first language also helps in promoting a sense of healthy biculturalism (Poul 413).
Brown should adopt a policy that supports cultural conservation. This will be adopted by arguing that; Since California is the majority linguistically diverse state in the whole world, it is loosing its history and rich heritage particularly with regard to the indigenous languages. The only way to revive this is to introduce bilingual education which not only assists in acquisition of skills but also helps in maintaining and continuity of the Native language. This would be very important in maintaining origin and culture (Corson 213).
Recommendations
By forcefully evicting people living on the oil rich reserves, Brown risks being charged against violation of rights, the only option that he has if he wants to continue exploring the oil reserves is to offer bilingual education to the Native American Indians. He however must have facts to protect himself since the decision is very challenging because, once this is implemented the government will have to incur additional funding and there will also be many criticisms by other individuals.
To successfully pass his point through, Brown should have good knowledge of education rights and how he can justify his actions that he is still operating under the law. To do this, he must promise education to the Native Indian tribes in California.
Brown should convince the other tribes that, being that majority of the Native Indians are English learners and that, according to their population, they are the majority people affected in education sector, and they constitute a unique and special group that needs quick and very special attention.
This will seclude them from the other minority tribes. While dealing with this situation, the other tribes should also be promised that, once the situation stabilizes they will also be considered. This is because when a problem occurs, it is justifiable to start handling the major and key areas then summarizing with the less affected areas.
This will be a great defense given that it will be backed by the population numbers which are clearly available. Native Indians form over 3.1 million of the 5.5 million English learners in the United States (Trujillo 32).
Concerning the funding of the bilingual education, Brown should show facts of how the anticipated exploration is aimed at raising adequate funds capable of funding education and contribute to economic development as well. Through this, economists should provide estimates capable of convincing the general public of the advantages of exploration and how this will contribute towards bilingual education without necessarily involving much of the states funds.
Pros and Cons of Information Presented
Section 15-753 provides an exception to English teaching; it thus gives room for bilingual education. Those who are English learners should be educated through English Immersion for a period not more than one year. This challenges the bilingual education offering since, it limits the years to three. Through the three years, one might not have attained full understanding of English; this will create major conflicts between Brown and the Native councils.
Since elimination of bilingual language has in the recent past shown an increase in performance and total score of students, that is students under English immersion recorded greater performance than those under bilingual programs, there was an upward trend shown in Stanford-9. It is evident that, bilingual programs do not work best for the learners.
It is better if it is done away with. On the other hand, people hold that, bilingual education helps students in learning Basic English skills (Bruce 378). However, if they are used for more than three years, then they are ineffective. The question of how long they should be used remains a challenge because no one will be very keen to count the years and thus put an end to its use in learning institutions, some teachers given this loophole, will continue using it way beyond three years.
Because of the exceptions in the proposition 227, Brown has a loophole for exercising his decisions regarding bilingual education without being seen as a violator of the law. He can also support his actions as a way of protecting culture of the Natives to make sure that the diversity is reduced within California and its environs.
Approach to be Pursued
Brown should consider offering the bilingual education demand to the Indians since this is the only option available. If he does not settle for this, he will risk infringing property rights of forcefully evicting people. Since proportion 227 has an exception, he should use this to his advantage to ensure that, he proves to the general public that he still acts within the law.
Because the native Indians falls under the category of the English learners who are privileged to bilingual education before acquisition of English skills, the law will act on his advantage. Section 15-753, gives an exception that, English learners children should be passed through bilingual education before they completely learn English (Poul 72).
Citing from Education code section 220, Brown can support the funding of bilingual education by arguing that, since the law prohibits discrimination on ethnic group, sex, religion, national origin or physical disability, from benefiting from state financial assistance (Keiko and Annette 47).
This means that, both the Indians who are not English proficient should also have the right to facilities just like the other English proficient students. They should therefore benefit from funds by the government and the state should finance their choice of learning without any form of discrimination. This section will act to the advantage of Brown when it comes to financing bilingual education. It justifies the use of state finance in education purposes.
The person who is eligible to file a case against financial support to any kind of education programs by the state, should prove that, the state has discriminated against; race, sex, color, disability, age or national origin.
This is not easy because, for anyone to file a case against Brown for funding, bilingual education, he will have to present substantial information which in this case is not available since these people are members of the state who have equal rights to education just like the other citizens. It therefore beats logic that they should be accorded the attention and support that they need when it comes to education.
Brown should also tackle the issues via dialogue approach where, he calls the council members in a series of meetings in order to make the terms and slight variations deemed necessary. This will ensure wholesome agreement and prevent future problems which may result from the action agreed upon.
Conclusion
It is evident that, the use of bilingual language is both beneficial to the learners and will also benefit the state as well since exploration of the oils will continue and this will not only benefit the government but the natives as well. Language diversity in California will also have been eliminated since; bilingual education will promote the use of local languages in education.
Therefore, it is important and necessary that Brown provides bilingual education to the Native Americans (Indians). Because of the exceptions in the law, the state will not have contravened the law but it will be operating within its limits.
Works Cited
Bruce, Jahensen. The Native Peoples of North America: A History. New York, NY: Rutgers University press publishers, 2006. Print.
Corson, David. Language Diversity and Education. New York, NY: Routledge Publishers. 2000. Print.
Keiko, Koda and Annette, Monica. Learning to Read across Languages: Cross- Linguistic Relationships in First- and Second-Language Literacy Development. Boston: Routledge Publishers, 2007. Print.
Poul, Flethcer. Language Acquisition: Studies in First Language Development. Cambridge: Cambridge University press publishers, 1986. Print.
Trujillo, Monica. “Bilingual Education in California: Is It Working?” Penn McNair Research Journal, 1.1 (2007): 13-56. Print.
Construction is a separate independent branch of the state’s economy, which is necessary to commission new buildings and structures. In addition, reconstruction, expansion, repair, and technical re-equipment of existing production and non-production facilities. The defining role of the construction industry is to create conditions for the dynamic development of the country’s economy. The construction industry is of great importance in the development of the state: the economic efficiency of related sectors of the economy is primarily ensured by the intensive development of construction. The specifics of the industry are explained by the nature of its final products, specific working conditions, several specifics of the equipment used, technology, organization of production, management, and logistics.
Main body
Construction refers to the sphere of material production, i.e., to the industries that create material goods. The products of the construction industry are plants and factories built and put into operation, railways and highways, power plants, shipping channels, ports, residential buildings, and other objects that form the fixed assets of the economic complex of the country. In addition to the creation of fixed assets, the functions of capital construction include the expansion, reconstruction, and technical re-equipment of existing fixed assets. Therefore, the main task of capital construction is the expanded reproduction and qualitative renewal of fixed assets in all sectors of the country’s economy. Thus, capital construction creates material conditions that ensure the possibility of functioning the means of production.
Due to the coronavirus, there were failures in the supply chain, which caused the construction industry to suffer quite a lot. In addition, the rise in prices for building materials provoked the unfinished construction of some objects. Due to the combination of all factors, there was a decrease in production volumes in the construction sector. Likely, the growth rate of the construction industry in the United States will reach an average of 4.7% during 2021-2025 (BusinessWire, 2021a). This indicator consists of the need to build municipal institutions, for example, hospitals, since the coronavirus provoked an urgent need for this type of institution. Moreover, the states offer their residents favorable mortgage rates for primary real estate, which also contributes to the growth of the construction industry.
There are various companies in the construction industry that occupy different market shares and have different sizes of the enterprise itself.
Such companies include Jacobs Engineering Group, Lennar Corporation, Fluor Corporation, and others. There are quite a lot of companies involved in the construction industry, and therefore the competition is also relatively high, thanks to which prices are still at an acceptable level for residents of different countries. The global construction industry can reach $10.5 trillion by 2023 (BusinessWire, 2021b). However, at present, of the pandemic, construction prices are high as the coronavirus has provoked a delayed demand for real estate and an increase in these prices.
The latest political changes that have taken place in the construction market are related to the coronavirus pandemic. Due to the economic crisis, which manifested itself through the lack of customers in many institutions and companies, people began to invest in real estate. The state authorities supported this step and developed several preferential mortgage programs. Due to the desire to satisfy the demand for real estate, developers have been more actively engaged in construction. As a result, new residential buildings, non-residential premises, and other types of objects under construction began to appear, which allowed the construction industry to grow and flourish even during the epidemic.
Construction is especially closely connected with the industry. On the one hand, the increase in construction volumes depends on the development of initiatives that provide its technical equipment: machinery, materials, structures, electricity, etc.; on the other hand, performing construction and installation work for different sectors of the economy based on contract agreements, construction organizations are inextricably linked with the activities of customers. Several other industries act concerning construction both as suppliers and as consumers of construction products.
Still, the epidemic has caused some problems for the construction industry. Restrictive measures taken due to the pandemic led to the shutdown of some enterprises and construction projects, the demand for construction products decreased, and delays in the delivery of goods began to occur. In addition, suppliers have already announced an increase in prices for consumables: the cost of some of them is tied to the dollar exchange rate, which is currently unstable. Plans are being disrupted at several construction sites, and it is unclear when they will be able to return to the original schedule since some types of work are seasonal.
Conclusion
In conclusion, the construction industry is one of the largest industries that has undergone both ups and downs. Nevertheless, it continues to thrive, despite the increase in prices associated with the pandemic. This is facilitated by the active demand of the population, which provokes the purchase of construction projects to invest money. In this industry, competition is at a high level, but companies remain afloat and continue to compete. People predict growth in the construction industry in the future, but still, various circumstances may appear that may lead to a drop in prices for objects, materials for construction, etc.
References
BusinessWire. (2021a). 2021 United States Construction Industry Market Size & Forecast, by Value and Volume Across 40+ Market Segments. Web.
BusinessWire. (2021b). Global Construction Industry Report 2021: $10.5 Trillion Growth Opportunities by 2023. Web.
The Construction industry creates a very important part in the development of the economy of a country. This offers good job opportunities especially to the professional field and experienced workers with very attractive earning scales ( Bureau of Labor Statistics, 2008). Since the industry is very broad, there is need for proper organization which justifies its division into three organizations as explained below.
Types of Organization in The Construction Industry
The organization of the Construction Industry can be described in a number of ways depending on the types of work and activities that are carried out. According to the United States Department of Labor, the Construction Industry is divided into three main segments. These segments are classified depending on the type of work executed and include the Construction of Building segment, Heavy Civil Engineering Construction, and lastly, Specialty Trade Construction (Bureau of Labor Statistics US D.O.L, 2008-9).
These types of organizations combined will provide very important goods and services such as schools, houses, warehouses, factories and many more thus making construction very beneficial. Below are the descriptions of these types of organizations:
The Building Construction Organization – General Contractors
In this category the contractors are referred to as general contractors and these will generally build residential, industrial, commercial, and other related buildings in the industry (Bureau of Labor Statistics US D.O.L, 2008 – 9). According to Schexnayder J. Clifford and Richard Mayo, there are three sub-divisions under this type of organization. Below are the comprehensive descriptions of the sub-divisions under this category:
General Contractors (Residential) – This is where contractors and developers involved are concerned with building homes, apartments and other important living facilities (Schexnayder J. Clifford and Richard Mayo, pg. 37). Construction of these individual homes is grouped into custom homes that match buyers’ needs and standard designs and floor plans that are offered with limited options and upgrades. Generally, there is no bidding for tenders in this category. For that reason, therefore, negotiation with owner is done in case of the execution of custom designs. On the other hand, for the case of provision of standard designs and floor plans, announcement of price is the condition. The process is therefore quick and cheap than all the other ones.
Operative Builders – This category involves the construction of facilities such as stores, schools, office buildings and many other but related built structures. The projects in this category range from small units to multi-million dollar projects such as minor single unit stores to tall office buildings and casinos (Schexnayder J. Clifford and Richard Mayo, pg. 37 – 38). For this category, both government and private owners can undertake such contracts where bidding is used for government agencies and negotiation of the prices of proposed buildings is done in the case of private owners.
General Building Contractors (non – residential) – In this type of organization, the contractors’ work mainly involves the construction of large buildings and warehouses such as electricity generating facilities, automobile assembly plants, hospitals and clean rooms just to mention among much other construction. According to the classification at the United States Department of Labor, this category generally falls into two groups dealing with the construction of industrial buildings and non-residential buildings other than industrial buildings and warehouses (SIC Division Structure US D.O.L, 2008 – 9).
Heavy Civil Engineering Construction
Under this category, the main works carried out include the construction of roads, sewers, bridges, highways, tunnels, and other existing projects (Schexnayder J. Clifford and Richard Mayo, pg. 38 – 39). According to Schexnayder J. Clifford and Richard Mayo, such contracts are generally awarded in a low bid and the government is the usual owner but not individuals as the projects are of expensive nature. This is divided into two groups namely: Highway and Street Construction and secondly, Heavy Construction except for highway and street construction (SIC Division Structure US D.O.L, 2008-9).
Specialty Trade Construction
This is a special type of construction that involves the performance of specialized activities that are related to the construction industry example being electrical, painting, plumbing, roofing, and painting work (Bureau of Labor Statistics US D.O.L, 2008). Contractors in this category can work on a subcontract awarded by the general contractor or work directly under the owner performing only a portion of the whole contract. Due to the specialty of this category of organization, the contractors are therefore specialists in the specific areas they work and this improves on quality of services that are provided. This can also make management of site works efficient.
The Organization in Building Construction
This generally includes general contractors and operative builders who engage in construction of residential, industrial and commercial structures and their roles are as explained below according to each respective group and their sub-divisions as possible:
General Building Contractors-Residential Building
This category deals with the pure construction of residential buildings. The types of construction are classified into the following two divisions as already pointed above:
General contractors (single-family houses) – Here, the building contractors generally deal with the construction of single-family houses as shown. These are usually small construction activities that can be undertaken by any small size contractor and these can deliver in all areas such as totally new work, repair, remodeling and any alterations as per the specified contract (SIC Division Structure US D.O.L, 2008). Generally with this kind of construction, there is no bidding for tenders and instead, negotiation with owner is a common phenomenon in the executions of most projects.
General contractors (Residential buildings other than single-family houses) – The general contractors in this class deal with the construction of residential buildings other than single-family houses and are responsible for all the services that could be offered including repair, alterations, additions and remodeling. Just like in single-family house construction, there is no bidding for tenders and negotiations with the client are done to ensure profit maximization by the general contractors and operative builders taking projects (Schexnayder J. Clifford and Richard Mayo, pg. 37).
In this sub-division general contractors have licensed professionals and they will take a project as per some specific agreement involving plans, specifications, and the documents required for the project in question (Answers.com, 2005). The specific documents are usually documented by a written contract where the responsibility of the contractor is limited by the items that are designated in the contract documents. The contractor, as well as the owner or developer, is usually referred to as a builder and the general contractor is one that enters into contract with the owner so that he constructs the owner’s projects as per the terms and conditions of the contract (Answers.com, 2005).
Operative Builders
These builders are also referred to as speculative or merchant builders since their main purpose is to produce buildings for their own for-profit purposes as opposed to general contractors who bid for projects. In this type of classification, the operative builders enter into the construction of single to multi-family houses and other buildings specifically on their own account rather than as contractors. On the other hand, their engagements in the construction of buildings specifically for lease on their own accounts are classified under Real Estate (SIC Division Structure US D.O.L, 2008). Some of the builders that undertake this type of construction include: The Condominium developers on their own account, Cooperative apartment developers on their own account, Operative builders on their own account and speculative builders on their own account (US Census Bureau, 2003).
General Building Contractors – (non – residential)
This building organization is classified into two categories as described below:
General contractors – (Industrial buildings and warehouses)
General contractors in this case deal with the construction of warehouses and buildings such as automobile assembly plants, commercial warehouses and clean rooms. For this type of construction, the contractors undertaking the works are usually specialized in the specific kind of work they do. They deal in repair work, remodeling, and alteration. As a way of pricing such contract, the contractors are empowered to negotiate the price of the relevant work (SIC Division Structure US D.O.L, 2008).
General contractors (Other than Industrial buildings and warehouses)
This type involves the construction of non-residential buildings except cases of industrial buildings and warehouses by general contractors Examples of built facilities that are a product of this category include buildings such as religious, recreational and institutional buildings. Therefore, this category covers general contractors that undertake projects in construction, repair, new works remodeling and renovation of non-residential buildings other than industrial buildings and warehouses (High Beam, 2009).
Heavy Civil Engineering Construction Organization
According to the United States Department of Labor, this major division includes general contractors who engage in heavy construction apart from other buildings for example construction of flood control projects, highways and streets, marine construction, bridges, and irrigation projects just list (SIC Division Structure US D.O.L, 2008). Heavy civil engineering construction is divided into two sub-categories which are very important and provide the following services in the construction industry:
Highway and Street Construction except for Elevated Highways
Under this subdivision, special trade and general contractors are responsible for the construction of roads, public sidewalks, airports and related constructions apart from the construction of elevated highways (US Census Bureau, 2003). The provision of this built structure eases the development and smooth operation of the general construction industry. For instance construction of high-class-highways, bridges and roads improve the movement of construction materials to building sites therefore providing a perfect solution to efficient management of activities leading to entire growth of the industry.
Heavy Construction except for Highway and Street
This sub-group is divided into three parts or sub-types depending on the type of construction activity that is undertaken and their functions are as described below:
Bridge, Tunnel and Elevated Highway Construction – the general contractors are experienced and undertake all these construction activities depending on their areas of specialization. There are more of these construction activities including the construction of railway tunnels, pedestrian tunnels and highways (US Census Bureau, 2003).
Water, Sewer, Pipeline, and Communications and Power Line Construction – According to the United States SIC structure, general and special trade contractors carry out this construction works so as to provide perfect functional sewer service as an example, to service the existing population (SIC Division Structure US D.O.L, 2008).
Heavy Construction, Not Elsewhere Classified – These may be very large and unique projects that do not fall under any of the described classifications. General and special trade contractors provide this important solution in the construction industry.
Specialty Trade Construction Organization
According to United States Department of labor and Census Bureau in this category, the special trade contractors are specialized in the activity they undertake either to building or non-building products or both of these. Some of these activities may include paintwork, plumbing works, and electrical works just to mention some of them.
Mostly these special trade contractors work under the general contractor so as to deliver a specific service such as installation of electrical works or may also work directly for the employer. These contractors usually do their work at the construction site but they also could have areas where they can do works that relate to the current work. Below are the various sub-divisions that make up the specialty trade contractors:
Plumbing, Heating and Air Conditioning services in Built Facilities
Plumbing, heating, air-conditioning and other related works are done by the specialist contractors in this category and this ensures that quality work is done. These are very important services to any building and are of great importance to the construction industry. These services are usually provided in the final stages of a building so as to provide the required operation of the built facility. Air-conditioning is usually provided to large commercial buildings, warehouses, control, and clean rooms and more depending on the tastes and preferences of the owner of the particular structure or built facility. Delivered works are of high standard due to specialization.
Painting and Paper Hanging works – Since painting is what gives a structure aesthetic value and resistance from adverse weather conditions, it is therefore justified to give it adequate concern. The special trade contractors therefore mainly engage in painting of finished structures and paper hanging. Those trade contractors involved in roof painting however are classified under a separate industry type. Some of the activities carried out by trade contractors in this category include: Painting of buildings and other structures – except roofs-contractors, Electrostatic painting on-site – (including lockers and fixtures), and Ship painting-contractors services among other services that are offered by the trade contractors (SIC Division Structure US D.O.L, 2008).
Roofing, Siding, And Sheet Metal Work construction
In this type, the special trade contractors are concerned with the installation of roofing, siding and sheet metal work respectively. This is a very important trade and the sub-categories that are generally dealt with include: Architectural sheet metal work-contractors, Ceilings, metal, erection, repair, construction and Coppersmithing, all in connection with the construction contractor (SIC Division Structure US D.O.L, 2008).
Conclusion
As a conclusion to the above discussion on the organization of the Construction Industry, we can summarize that the efficient organization of the Industry explains the proper planning and operations in the actual field. This, therefore, lead to the growth of the Industry from one level to another.
Works Cited
Answers.com, The Worlds leading Q & A Site. General Contractors- residential buildings, other than Single Family (SIC 5522), 2005. Web.
High Beam, Business. General Contractors for Non-residential Buildings other than Industrial Buildings and Warehouses, 2009. Web.
HOMETIME.COM: Electrical. 2009. Web.
Schexnayder J. Clifford and Richard Mayo. Construction Management Fundamentals: 1st edition. New York: McGraw-Hill Companies Inc., 2004.
UNITED STATES DEPARTMENT OF LABOR. Career Guide to Industries, 2008. Web.
UNITED STATES DEPARTMENT OF LABOR: SIC Division Structure. 2008. Web.
U.S. Census Bureau: Specialty Trade Contractors. 2003. Web.
U.S. Census Bureau: 237 Heavy and Civil Engineering Construction. 2003. Web.
The significance paid to the fire safety of buildings under construction can be thoroughly justified. With such buildings providing a site for dangerous construction processes, the fire statistics for such buildings can be understood. It is stated that buildings under construction are vulnerable to damage from fire, where the estimations of Health and Safety Executive (HSE) state that “around 11 construction fires every day” (UK Timber Frame Association). The significance of the fire safety issue in buildings under construction can be also seen through the financial losses incurred by such incidents. According to the Fire Protection Association (FPA), in the period from 1991 to 2005 construction fire losses reached £120,641,238, with the ratio of serious fires by occupancy for construction reaching 70% for the same period (Passey). The importance of fire safety on construction sites can be specifically emphasized in high-rise buildings, providing temporary housing for migrant workers. The latter can be explained through the problems that might result from short-circuit and overheating dangers, resulting from occupants altering the electricity/gas supplies, and the different life risks associated with high buildings. In terms of the latter, the challenges posed to fire fighters in high-rise buildings under construction are more complex, with the buildings designed so that people are rescued internally, rather than externally.
In the light of the aforementioned, the present paper provides an overview of the fire safety issues in buildings under construction, identifying strategies that will enable reducing the number of fatalities and injuries which result from fires in such buildings. The paper will be structured in report form, deriving the analysis format from Problem Orientated Partnerships (POP) framework (Lancashire Fire and Rescue Service Problem Oriented Partnerships: Quick Guide).
Scanning
The fire safety issues that might be involved in buildings under construction vary in their nature. Generally, they can be categorized into the following:
Design problems.
High risks sites.
Occupancy.
Fire fighters’ access.
Such categories are not inclusive, where there other problems that can be identified, but nevertheless, those categories can be seen sufficient to classify the needs for an effective fire safety strategy. Most of these categories are addressed in The Joint Code of Practice on the Protection from Fire of Construction Sites and Buildings Undergoing Renovation, a non-legislative framework that provides guidance on the safety of buildings under construction.
In terms of design, the issues that might arise involve the compliance with fire safety standards in the intermediate stage during the construction and prior to the buildings’ operational phase. The lack of a safety design at this stage implies that the systems that would be available during the operational stage might be omitted, out of order, or not accommodated for use. It should be noted that the latte can be driven by the fact that “[d]uring the design and construction phase of a project, the emphasis is typically on the fabric of the building – , after all this is what drives the project finances and is the focus of the design” (n.a.). The aspects affected by deficiencies of the safety design might include means of escape, which in high-rise buildings might receive a specific consideration, alarm systems, fire-fighting means and aids, e.g. water supplies, and other factors. The aforementioned aspects can be seen at an intersection of the competencies of many parties and agencies, including fire and rescue services, building designers and architects, contractors, and others.
The high risk site factors can be related to such aspects as the storage and the handling of combustible materials, where construction sites contain “[m]any solids, liquids and gases can catch fire and burn” (HSE). High risks can be also associated with hot works, electrical installations, smoking rules, and the storage and disposal of construction waste. The responsibility of such aspects might involve different stakeholders as well, where in addition to the parties and agencies mentioned previously, a part of the responsibility will be taken by the workers, and their corresponding awareness of fire safety rules.
The workers might have an impact on the safety of the construction site as well, specifically in cases when the building under construction is used as a temporary housing. It should be noted that generally such aspect as occupancy of buildings under construction is subject to several rules and regulations. The latter can be seen through the example of Canada, namely the laws in Alberta put specific conditions on the number of situations such occupancy might occur. Such conditions include, but not limited to, the following situations:
The building is multi-unit and built in phases, where each phase is used to finance the other.
The building is industrial, where the office area is completed before the exterior finish and roofing materials are installed in the shop area.
Building a wing of a hospital, while the rest of the facility is in use (Alberta Municipal Affairs 1).
Such situations are governed by several provisions, including the Building Code and the fire code. Additionally, none of the latter implies the absence of the usual building accommodations, characteristic to the parts of the buildings in which the construction is still ongoing. For example, in terms of electricity, water, gas supplies, and ventilation the requirements include that all of those systems are complete and operational for all the storeys, including the ones to be occupied (Alberta Municipal Affairs 2). In that regard, with the possibility of migrant workers residing within the building under construction as well as the fact that inoperable systems have to be manually modified by the workers to accommodate their needs, such fact implies a certain risk factor that should be acknowledged when developing the fire safety strategy for such buildings.
The problem of fire-fighters’ access in buildings under construction can be seen specifically in high-rise buildings. Such problem can lead to a number of complex and high-risk situations, including, but not limited to the following:
Limited or delayed accessibility to upper floors.
Wooden ladders and platforms between floors.
Wooden formwork.
Disorientation between floors.
Structural collapses (TERPAK).
In addition to the factors associated with high-rise buildings under construction, there are several risk factors which hinder fire-fighters’ access in buildings under construction in general, regardless of height. The latter includes inflammable construction materials, wind driven fires, construction elevators, limited accessibility to the site, and others (TERPAK).
Analysis
With the previous scanning section being concerned with the symptoms of safety problems in high-rise buildings under construction, the present section is mostly concerned with “establishing the root cause(s) of the problem (why that problem is happening/what’s fuelling the problem) (Lancashire Fire and Rescue Service Problem Oriented Partnerships: Quick Guide). It can be stated that the main factor contributing to the occurrence of the aforementioned “symptoms” can be seen in the absence of clear guidelines that will govern the all the processes and the relations between all the parties and agencies involved in the constructions process and during the construction period.
The latter is not only concerned with the process between stakeholders, but also within them as well, specifically concerning site operations and accommodations of workers. In that regard, even negligence as a factor can be seen related to the absence of control regulations for safety measures. The significance of such an issue cannot be underestimated, where “[a] series of high-profile fires over the past few years in buildings that were still under construction have brought the issue to the fore “(Luke). Thus, in order to improve fire safety, the regulations should provide an outline of the procedures that should regulate the control over the risk factors on the site as well as govern the interactions between all the parties involved. An example of such regulations can be seen through the practices prescribed in the Joint Code, which despite being initially concerned with tunnelling, is applicable to other projects as well. Such practices, for example, regulate the office accommodations available on site, in terms of the area, dimensions, and the allowance for persons (Chudley and Greeno 98). Modifying and applying such regulation to migrant workers, providing them with housing conditions can be seen as a suitable options, which will be controlled by the owner of the site and fire service agencies, where construction licences can be issued based on following such requirements. The latter is only an example, although it can demonstrate how regulation the relations between two agencies can improve the overall fire safety of the building.
Response-Strategy
The first stage of the strategy to increase the safety of high-rise buildings under construction can be seen as the construction site requirements control. A group should be formed from representatives of fire and rescue, health and safety, and construction, design and management (CDM). It should be noted that such group will focus on the safety of the construction site, rather than the safety requirement of the operational building. In that regard, the focus on innovative approaches to fire safety in building design and constructions as well as its control can be seen as the responsibility of fire and rescue services (Lancashire Fire and Rescue Service “Community Safety Strategy 2009-2014”). The newly formed group will outline the framework that will regulate the following critical aspects at the construction site:
Workers’ accommodation – such aspect will be concerned with the location of the housing units for migrant workers at the site, electricity, water and gas systems, ventilation, the location to materials storage, etc. Additionally, such aspect will consider bringing “the rules on smoking to the attention of all workers and visitors to the site and enforce them” (HSE).
Hazardous materials -such aspect will be concerned with the location, the storage conditions of all combustible materials and ignition sources and the prevention of authorised control. Accordingly, the regulations of such factors can be based on the best practices covered in The Joint Code of Practice.
Accessibility and escape – such aspect will outline the establishing safety standards for the following:
Evacuation plan procedures.
The location and the quantity of fire extinguishers, smoke detectors and fire alarms.
Routes of access to the site by fire-fighters.
Orientation signs.
The location the nearest water supplies.
Such aspects are to be discussed in workshops, the result of which is the formation of the Construction Site Fire Prevention Checklist (Luke). Such list will serve as an aid for the control procedures and the measurement of the risk and the vulnerability of a particular building under construction.
The next stage of the safety strategy can be seen in providing training sessions for the new regulations. Such aspect can be achieved through expanding the Integrated Personal Development System (IPDS), introduced to the Fire and Rescue Service in 2003, to cover the following aspects:
Training the personnel on the control procedures.
Develop training sessions for contractors on the new requirements.
Develop training sessions for workers.
Provide a system of certification for the workers, according to which workers with certificates conform to the minimum knowledge level, necessary to maintain safe working environment.
Regularly update the certification and the learning materials.
The next stage of the strategy can be seen through implementing enforcement and control of the established requirements and regulations. The control aspect will be concerned with establishing a regular procedure according to which construction licences will be given, the procedure for testing the requirement using the Construction Site Fire Prevention Checklist, and the subsequent control. Accordingly, different rates/percentages of risks will be determined through the checklist, and according to which different enforcement will be determined. In that regard, the role of the Fire and Rescue Service will be in making sure that the requirements are followed, the acceptance of which will lead to providing the licences and permits by Building Control Body (BCB) and local governments (Communities and Local Governments). Based on the example of the Joint Code of Practice, the enforcement processes can be connected to insurance companies, which will have the right to reject insurance requests for buildings not complying with the established regulations.
The final step in the strategy can be seen through evaluation. The evaluation will be based on specific metrics which will be used to assess the success of the strategy. These metrics might include the number of injuries and fatalities, the number of rejected buildings due to compliance failures, and others. Accordingly, a period will be established for the strategy to be reviewed and modified if necessary.
Conclusion
The present report provided an overview of the safety issues that might arise in high-rise buildings under constructions. The report identified the problem areas in the settings in questions, their symptoms, and the main stakeholders. Additionally, the report analyzed the causes of the problem and formulated a general strategy aimed at improving the fire safety of the aforementioned construction site. In that regard, it can be concluded that the significance of fire safety in construction sites cannot be overestimated. The large number of fire incidents involving buildings under construction implies that the regulatory mechanism in such areas is far from perfect, and thus, the present report attempts to close the gaps in existing practices. It should be noted that the example of the Joint Code of Practice, although not legislative, provides a wide range of best practices that can be adopted when implementing the strategy proposed in the present report.
Works Cited
Alberta Municipal Affairs. ” Occupancy of Buildings under Construction “. 2008. Alberta Municipal Affairs.
Chudley, R., and Roger Greeno. Building Construction Handbook. 6th ed. Amsterdam ; Boston: Butterworth-Heinemann, 2006. Print.
Communities and Local Governments. “Planning, Building and the Environment”. 2009. Communities and Local Governments.
The pyramids of Giza remain one of the most amazing works of ancient times. Aged over 4500 years, it is widely held that their construction was mainly meant to create a burial place for pharaohs and in particular three pharaohs, namely, Khufu, Khfare, and Menkaure (Clarke & Engelbach, 1990). The pyramids are a true revelation and living proof of the excellent mathematical skills, project planning ability, as well as constructional and organizational skills that the ancient Egyptian’s possessed. However, the most astonishing thing is how these magnificent pyramids could have been created without the assistance of the specialized equipment used in modern-day construction. Both theorists and scientists have often attempted to answer these questions.
Main body
As has already been mentioned, there are vast theories put forth by leading Egyptologists as to the exact ways through which the pyramids were constructed. Most theories are often premised on the supposition that ancient Egyptians would have literally found it impossible to construct the pyramids had they relied on the primitive methods associated with them during the times of construction. Most theories have therefore opted to rather than focus on archeological evidence, premise their arguments on suppositions. One rather outstanding theory is the one proposing the use of ramps in the construction of the Pyramids.
The hypothesis proposing the usage of ramps and sleds largely dwells on a hypothesis that there was a large team of laborers who pushed stones with the assistance of wood-made sleds up a single ramp to connect the quarry and the pyramids under construction. However, this theory has been disputed with its critics citing that such sleds would have required more resources than the pyramid itself. Another of the theories is Herodotus’ Lever and Pulley’s theory. In this theory, Herodotus proposes that the stones used to construct the pyramids were lifted using a series of levers and pulleys (Boxer, 1987). Although many have criticized this theory, some proofs have been found to render some credence to the proposition including small wooden gadgets also known as rockers.
An interesting and rather fascinating theory of recent times is the one proposed in the book, ‘The Phoenix Solution’ published in 1998 (Alford, 1998). In this book, the author advocates for the adoption theory where he argues virtually all archeological evidence is consistent with the fact that Egyptian kings adopted structures that already existed and used the same as the foundation for the construction of the pyramids. As a matter of fact, he goes further to propose that the Kings in essence only added causeways that ran amidst the mortuary and the valley temples. Considering how taxing this task would have been, the theory amalgamates the fact that the villagers must have participated in large numbers to aid the construction.
Conclusion
It must be noted that the adoption theory presents a rather realistic view of how the pyramids were constructed. The evidence of workers found in 2003 further gives credence to the argument that a large pool of villagers engaged in the construction although it does not explain how stones were lifted. However, with pre-existing structures hypothesis, this question is well answered. In essence, more credence can be given to the adoption theory as compared to multiple other theories that are often susceptible to being discredited on basis of factual information.
References
Alford, F. A. (1998). Phoenix Solution. London: Wembley Publishers
Boxer, S. (1987). Herodotus’ theory of how the pyramids were built gets a lift. Discover, 8, pp.23-24.
Clarke, S. & Engelbach, R. (1990). Ancient Egyptian Construction and Architecture. New York: Dover Publications, Inc.
Tribune Tower, which was designed in the 1920s by John Mead Howells and Raymond Hood, is one of the clear examples of works of the first Chicago School of architecture known for being a pioneer in the development of skyscrapers. The construction of such buildings marked the beginning of the industrial era in the United States. The need for new technologies was conditional upon the previous experience of architects related to the destruction of the city by Chicago fire of 1871. It also reflected the need for a new approach towards the living space people use. Therefore, the buildings were planned to be functional and safe for people. The idea of usefulness and safety was further developed by other architects and shaped the city one can see today.
Figure 2. Map of Campus and the Neighborhood, 1969 (Skidmore and Netsch).
The map of campus and the neighborhood of University of Illinois at Chicago Circle was made by architects Owings and Merrill Skidmore in 1969. The construction plan of the campus contributes to the idea of external simplicity of the buildings. This concept was popular among the architects and engineers of the first Chicago School of architecture. It was conditional upon the need for functionality in the future buildings. As a rule, all the decorations and ornamentations of these buildings were inside the rooms, not on the facades. The same applies to this campus plan, which is defined by straight lines and functional location of all the necessary premises.
Figure 3. Jack Knife Bridge in Raised Position Over the Chicago River, Dark Exposure (Chicago Daily News, Inc., photographer).
The inventions of the first Chicago School of architecture were not limited to the construction of skyscrapers. The use of metal skeleton frames also contributed to the development of construction of bridges in the city. Thus, for example, the Jack Knife Bridge, designed at the beginning of the 20th century by William Scherzer, appeared due to the emergence of such technologies. The bridges of Chicago changed transportation and, therefore, the economic life of the city and became architectural masterpieces of that time. Their construction was one of the best solutions for a city by the river and became the new sphere of architecture for the country.
Figure 4. Auditorium Theater, View Looking from the Back of the Theater Over the Rows of Seats on the Main Floor Toward the Curtained Stage (Chicago Daily News, Inc., photographer).
The building of the Auditorium Theater is one of the best examples of the ideology of the first Chicago School of architecture. The collaboration of engineers and architects allowed them to present the idea of external simplicity with internal functionality and ornamentations with the help of innovative materials. This type of building also contains the metal skeleton frame, which is the best solution in terms of safety and prevention of fire. Auditorium Theater, which was designed at the end of the 19th century by Dankmar Adler, is vital for architecture as it served as an example for other architects of the Chicago School. Its creation was followed by the construction of numerous buildings with the use of similar technologies.
Figure 5. University Hall Construction (Skidmore and Netsch).
The construction of University Hall, which was designed in the 1960s by Walter Netsch, contributed to the creation of Chicago’s image as a center of economic and cultural life. The buildings of that time were mainly intended for specific purposes, and they clearly reflected the idea of functionality above all. In the case of University Hall, the technologies were the same as the ones used for Tribune Tower or Auditorium Theater, despite the difference in their intended use. Thus, the functionality was combined with such elements as metal skeleton frames and the solution made of timber and steel beams. All these features made University Hall an excellent example of the first buildings of modern type in Chicago.
Works Cited
Chicago, 1930s, 1930-1940, Newberry Library, Chicago Architectural Photography Company. Web.
Bridge construction is a complex construction project that requires planning, implementation, and management. Contractors and government officials have been in an intense debate on better options for bridge construction, repairs, and maintenance. This paper evaluates the conventional and accelerated bridge construction methods based on cost, safety, and impact on public space. The prefabricated bridge component is a primary design of the accelerated bridge construction method (ABC) for new construction project, renovations, and replacement work (Alashari 50). PBES are structural elements manufactured off-site and transported to the project site for installation. These components include attributes that enable rapid construction and are fabricated with prime performance materials for strength, quality, and performance. Manufacturing off-site components permit contractors to operate at a steady state.
Accelerated Bridge Construction
Employee and Public Safety
A bridge construction project under hostile conditions is dangerous and complicated. For example, project activity on active highways creates traffic challenges for motorists and site workers. Site workers are forced to work under such conditions, and it affects the quality of work, productivity, and human safety. As a result, building workers are killed in work zones, making security a focus of transport agencies. Vehicular movement is influenced by the shift in the present transportation change and the consequences of on-site construction action (Jia et al, p. 7). Such development reduces work rate and efficiency among workers. Under the ABC methods, employee safety is guaranteed, and vehicular movements are unrestricted. Thus, the ABC method decreases the vulnerability of employees and drivers in dangerous situations. The most crucial method to enhance employee safety would be to eliminate traffic from on-site activities through a short-term diversion using ABC. Bridge constructions could bring significant consequences to utilities, road use, and the environment. ABC may be utilized to lessen work during sensitive allowable intervals.
Project Cost and Safety
Infrastructure projects such as bridge construction are expensive. However, the advantage of the finished project outweighs the expenditure. The fiscal costs of bridge constructions could be quantified by the cost of delivery and impact on economic growth. Under the ABC method, prefabricated components lower the project delivery time. By implication, the ABC technique reduces the financial cost to society (Accelerated Bridge Construction). The prefabrication process decreases the building cost through repeated use and a change of work environment from a dangerous work zone to a safe off-site location (Newnan et al, p. 350). Bridge construction jobs have a substantial effect on highway movement, delivery, and vehicular transport. Delays caused by building congestion and detours influence loss in earnings for road users. ABC can be deployed to mitigate such adverse impacts by reducing work time and improving road safety.
Conventional Bridge Construction
Under the conventional bridge construction method, the material strength is fortified with support beams to maintain a stable arrangement. Bridge structures are delivered on taxpayer’s money, and each deliverable should match the public interest. Therefore, bridge construction projects must be well-organized, economical, and aesthetic. Efficiency in construction focuses on strategies to achieve functionality while maintaining a cost-effective value of the project (Deshnur, p. 269). Bridge designers focus on exceptional designs because of technical, economic, and aesthetic pursuits. However, conventional bridge construction (CBC) is expensive when compared to the ABC strategy. Conventional bridge construction could be described as a joint-less bridge. The deck is constant and in monolithic relation to the support partition. The joints in most bridges raise the interest in joint-less beams and metal rods. Thus, conventional bridge construction is expensive in terms of maintenance, structure, and quality. The cost of installations prevents water seepage through the joints of metal beams. These bridges are safe for use and aesthetically pleasing because of the smooth and uninterrupted deck. CBC strategy prolongs work schedules, affects commuter movement, and logistics delivery. Such activities create traffic congestion, safety issues, and environmental risk to the community.
Bridge Failures and Construction Strategy
The primary causes of bridge collapse are not cluttered repairs or nonconformity from design criteria. Bridge failures result from extreme events where the support beams become weak to endure the burden of the strain. However, a bridge built with under specifications could still collapse. Contractors do not understand pressure-related stress and its impact on bridge integrity. This ignorance prevents policy-makers from enforcing engineering and project criteria that deal with exceptional ‘loadings’ because of climate and other natural events. In responding to a catastrophe, the contractor must integrate different variables to support quality repairs and effective decision-making process. Time, expenditure, quality, and security are cardinal elements in the preparation, building, and execution of bridge projects. When investors have the financial capability and skill to implement bridge rehabilitation jobs in vulnerable locations, the ABC method is the best choice. The decision-making process should incorporate a study of ADT, detours, emergency courses, and road user costs. Thus, in managing bridge failures, ABC offers a balanced strategy on price and public impact. The organization must use effective deployment tools for DOTs to determine the equilibrium and appropriateness of each technique. The public must be informed about the implications of poor repair strategy as it affects the environment. Conventions bridge construction affects street users by increasing travel time along the affected zone. Although road user impact cannot be removed, the challenges can be reduced to the minimum by applying controlled repair schedules. Taxpayer’s revenue funds bridge construction projects and the consequences of site diversions must be integrated into the planning procedure. The aim of the ABC is to lower the consequences of on-site construction activities, reduce on-site construction time, improve work safety, mitigate transport disruptions, improve quality, and life cycle expenses.
Budgeted Cost of Repairs
The assumptions state that bridge failures will occur in the year 25
Compounding interest rate = 5%
The cost of using the ABC method (Direct cost) = $75,000,000
The cost of using the ABC method (Indirect cost) = $100,000,000
The cost of using the conventional method (Direct cost) = $225,000,000
The cost of using the conventional method (Indirect cost) = $75,000,000
The total cost of using the ABC method if the bridge fails = 75,000,000 + 100,000,000 = $175, 000,000
The cost of using the conventional method if the bridge fails = $300. 000, 000
The probability of bridge failure (ABC) = 1/800
The probability of bridge failure (Conventional) = 1/500
Based on the cost of differential and the probability of bridge failure, the ABC method should be used for the repairs.
5/100 x 225,000, 000 = $ 8,750,000 for the first year
A compounding interest of 5% for 25 years = 8,750, 000 x 25 = 218,750,000
The principal amount = 175,000,000 + 218,750,000 = 393,750,000
Alashari, Mishal. ”Accelerated Bridge Construction (ABC), A Better Approach to Bridge Construction?” International Journal for Innovation Education and Research, vol. 4, no. 8, 2016, pp. 41-69.
Deshnur, Rahul. ”A Comparative study of Conventional RC Girder Bridge and Integral Bridge.” International Journal of Civil Engineering and Applications, vol. 6, no. 2, 2016, pp. 267-274.
Jia, Jianmin, et al. ”Multi-Criteria Evaluation Framework in Selection of Accelerated Bridge Construction (ABC) Method.” Sustainability Journal, vol. 10, no. 1, 2018, pp. 1-15.
Newnan, Donald, et al. Engineering Economic Analysis. Oxford University Press, 2017.
In today’s vibrant and economic world characterized by unprecedented uncertainties, insurance has become an important practice in the construction industry. With the increasing pace of technological advancement, many contractors have been forced to display high levels of construction techniques in the industry in order to attract many business opportunities. However with the changing nature of the environment, uncertainties and risks seem to hinder core construction activities in the industry. The resulting implications have occasioned gigantic losses both to the contractors and their clients. This dissertation is aimed at exploring the insurance responses shown by construction firms in the industry in their attempt to reduce their exposure to inherent risks in the industry
Introduction
Insurance is a term that refers to an equitable transfer of risk of loss from one business unit to another with an exchange of a premium to possibly reduce the adverse effects of that loss thereof in the event of risk occurring. Insurance has increasingly become an effective tool for managing risk in the construction industry. The modern construction work is sophisticated and requires contractors to make technical and professional decisions. However, with increased competitive pressures mainly triggered by a firms’ quest to incorporate new and expansive modern technological equipments, contractors often find themselves making wrong decisions thereby causing huge unexpected anomalies in the construction.
Professional indemnity insurance therefore accords engineers and contractors protection by indemnifying them against their legal liability to damages caused to third parties arising from their negligent actions and omissions perpetrated during the period in which they undertake their professional duties. It is a cover that lasts for one year and is intended to cover the firm only. Contraction work performed may fail to meet the client’s requirement specification and hence decide to lodge a complaint against such works. Professional indemnity ensures that the company’s reputation is not damaged by undertaking to compensate clients who feel that the company has not met their needs.
Background of the study
Construction industry is one of the major contributors of economic growth in each and every country. The dissertation attempts to look at risk as being among the factors prominently mentioned to deter prosperity in the construction industry. Most developed economies are characterized by robust infrastructure, magnificent estate development and property management. This can only take place when the operations and activities in the construction industry have been streamlined through capitalization and provision of adequate commercial auxiliary services like insurance. In fact, insurance remains a big pillar in the construction industry.
Relevance and significance of Insurance in the Construction industry
Construction is an industrial work in nature. It is widely known that industrial works are risky in nature. Contractors are exposed to dangerous activities that can easily claim their lives, cause damage to property and equipment or inflict an injury to any third party. Insurance therefore significantly reduces these risks through compensation in the event that the risk occurs. It is therefore perceived that insurance ensures business continuity in the construction industry.
Aims and objectives of the study
The aim of the study is to analyze the impact of different insurance policies and looks at diverse covers available to engineers and contractors in the construction industry. The study therefore tends to examine both existing and emerging new insurance policies in the construction industry and whether they are of importance in the current economic situations. The objectives of the study are;
To demonstrate the use of current insurance policies in the construction industry.
To scrutinize the provision of different insurance covers in the construction industry.
To find out the impact of insurance in the construction industry.
To evaluate the benefits of insurance in the construction industry.
The rationale of the study
The basis of the study is to look at the gap between insurance as a commercial practice and construction. Many construction firms are still reluctant to insure their organizations. As a result there has been a large public outcry as to the role of insurance in the construction industry and therefore the study aims to correlate insurance and construction as an activity.
Literature Review
The study is based on examining the impact of insurance in the construction industry. But before, it is important to understand the concept of principles of insurance and different policies that may be relevant to employees, contractors and firms in the industry in order to develop a clear picture in the industry.
The impact of insurance in the construction industry
Insurance has ensured continuity of business in the industry through compensation in the event that a major risk occurs. Constructions firms together with contractors as well as ordinary employees are assured of continuity after a major loss.
Construction firms are able to undertake promising but risky investments decisions which would otherwise not have been taken in the absence of insurance.
Professional indemnity seems to protect the firm’s reputation in the event that engineers accidentally breach any professional construction contract in the course of their professional duty.
Methodology
Problem statement; the problem here is to find out the magnitude of the loss that comes as a result of firms’ reluctance to insure their businesses. The dissertation aims at the impact of different insurance packages available to employees, contractors and company in the insurance industry. (Ranasinghe 2008) This can be discovered through the following research questions;
Can this research be used to embrace insurance in the construction industry?
Are the results appropriate in explaining the different insurance policies to the workers in the construction industry?
Hypothesis
Greater use of insurance will lead to increased construction services.
Insurance will make contractors to enter into risky construction activities.
Conclusion
Construction industry is dynamic in nature and consists of many risky activities. Insurance is the only way in which construction firms can be encouraged to undertake these activities. At the same time, a company must work with speed to ensure that they don’t incur heavy losses when there are insurance firms to mitigate adverse business losses.
List of References
Ranasinghe, M January 2008, Risk management in the insurance industry: insights for the engineering construction industry, Construction Management and Economics, Vol 16, no.1, pp. 31-39
The report looks at key design principles with specific emphasis on how axial and transverse deformation forces behave on tunnels. The mathematical relationship between longitudinal and transverse wave vibrations in the design and construction of underground passageways is considered. Parameters considered in the design process include peak particle velocities and other forces due to seismic movements. Circular and rectangular designs are considered in this report with special emphasis on the technical aspects in addition to varying excavation methods which depend on ground conditions. The report focuses on channel tunnel as a case study. The channel tunnel consists of three tunnels interspersed with pipes at an interval of 375 meters with two rail tunnels separated by a distance of 30 meters between which a central pipe 4.8 m in diameter runs. Relief ducts 2 meters in diameter connect the tunnels in a sequence of 250 meters. Controlled louvers supply fresh air regulating air conditions in the tunnel. Tunnel boring equipments assembled at the site cut through the marble and chalk along the line of construction. The boring machines’ cutting heads consisted of spinning blades, upon which forces were applied to enable penetration into the soil and rock. The rock and slurry were mixed to form a conveyable mucky product in the drilling and cutting process.
Aims
The aims of this project included:
Looking at the practical use of skills and techniques in underground tunnel design and construction by undertaking a study on channel tunnel as a case study.
Identifying the type of engineering equipments used in tunnel design and construction in different grounds.
How surveys are conducted for a proposed site for tunnel construction
The most important aspects of tunnel design and construction
Objectives
The objectives included:
Conduct an investigation into the principles and techniques of tunnel design and construction.
Identify specific engineering and design requirements for a rectangular and circular tunnel.
Identify specific deformational and compression forces acting on circular and rectangular tunnels.
Determine the techniques of analyzing soil and rock samples.
Identify the behavior of engineering component under different operating conditions.
Determine specific areas of future research
Definition of Terms
Deformation: A change in shape caused by external or internal forces acting on a body.
Ground particle velocities: These are three dimensional particle displacements induced by vibrations due to earth movements. This depends on successive rate of arrival of waves.
Force: That which causes an accelerating effect on a machine or an engineering component to cause a desired effect.
Young’s Modulus – This is a quantitative measure of a material’s stiffness. It is a ratio between the tensile and compression forces.
Modulus of Elasticity – It is the ratio between the stress and strain of a rock or any solid material.
Tunnel – An underground passageway constructed through rock or soil that can accommodate traffic moving from one point to another.
Tensile strength – This is the resistance of a material to tensional forces acting on it. It provides a value which determines the maximum amount of force a material can be subjected to without deformation.
Faults: A geological discontinuity that occurs in a rock mass resulting from tectonic earth movements.
Poisson’s ratio: This is a ration defining the stretch and compression effects on a body due to perpendicular forces and to axial forces in the direction of the force.
TBM: Tunnel Boring Machine used to cut through different types of rocks and strata. Different types of tunnel boring machines are used for with different designs
Introduction
Tunnels are underground passage ways dug in different types of rocks. Formidable challenges face engineers in the design and construction of such tunnels. These range from the appropriate use of technology to conducting underground research on the types of rocks and soils. Tensile and compression deformation forces and seismic activities in the proposed line of construction are important factors to consider in the survey and design process.
Background
The engineering project is a 50.5 km long undersea rail tunnel commonly referred to as the “Chunnel tunnel” connecting northern France and the United Kingdom. This complex structure is a display of engineering genius that took many years of survey, data collection, analysis in addition to other studies culminating in the design and construction of the tunnel. The tunnel is constructed through a geological line composed of chalk and clay. The chalk and clay layers include gray chalk, chalk marl, glauconitic and gault clay. It is a complex structure 7.6 meters in diameter with a 4.8 meters central service tunnel with a wide gestation time. Shafts from both ends of the tunnel provide ventilation and cooling system. A minimum vertical gap between both tracks in a monolithic reinforced concrete provides provision for track layout and flexible loading conditions on both ends. In 1973, a was treaty signed by the French president and British prime minister for the construction of the channel but construction did not start until later on. Tunnel boring machines some quite large were used in the boring process. Engineers faced challenges particularly with standing time for soft walls, collapsing walls, faults along the line of construction, different languages for tunnel workers, and other geological problems. But the construction of channel tunnel was a successful engineering project.
Key Concepts
Geostatic forces presented formidable challenges in tunnel design and construction for engineers working on channel tunnel. Key design concepts included an investigation into the axis of orientation of the tunnel, cross sectional size, shape, spacing between excavations, and an analysis of rock mass volume. Unit mass of soft and hard earth materials, lateral loads or forces caused by the earth’s vibrations, horizontal movements due to tectonic pressures and loads that exert stresses on tunnel were considered. Specific parameters for a design model before excavation started included a measure of the unit weight of earth (y), the modulus of elasticity (E), Cohesion (c), Friction angle (ø), Poisson’s ratio (v). These measurements provided data on specific properties for material to be used in excavation process.
Seismically induced forces due to earth vibrations and other stresses such as man-induced stresses are described by Price and Freit (2009) as virgin induced which act both vertical and horizontal. Vertical stress is due to weight overburden and horizontal stress is due to seismic tectonic movements. The average horizontal stress (K) is given by this expression:
K= Sn/Sv, where Sn are average horizontal forces acting on a tunnel.
Stress measurements are taken to determine stress fields. According to Price and Freit (2009) carrying out stress measurements involves using varying loads on a stress measuring instrument by stressing the original earth load to different sizes until the original volume of the earth load is achieved. The loading and unloading procedures help determine the tensile strength of a rock. Axial and transverse displacements of the soil due to seismic activities and their direction of propagation are key concepts considered. In addition, engineers considered both circular and rectangular tunnel designs by conducting a detailed analysis of effective wave propagation of the earth movement, the peak ground particle velocities, and peak ground particle acceleration according to the article on (Channel tunnel 23).
However, engineers were faced with the important challenge of determining wave propagation velocities and accelerations in the soil. Theoretical and actual values differed widely. This discrepancy was traced to the problem related to the soil’s compatibility.
The above diagram and table below illustrate the forces and wave motions under consideratio.
Wave type
Longitudinal strain (Axial)
Curvature
Shear
wave
General Form
Maximum value
e =(Vs/Cs)sinqcosq
emax =(Vs/2Cs) for q = 45
Ê/Ë ˆ¯ =AsCs2 cos3 qÊË ˆ ¯ max = As Cs 2 for q = 0
Rayleigh wave
General form
___________
Maximum value
e = VR CR cos2qemax =VR/CR for q = 0
ÊË ˆ¯ =ARCR2 cos2 qÊË ˆ max =ARCR 2 for q = 0
q= angle of incidence
r= Radius of curvature
Vs and Vr are the peak particle velocities
Cs and Cr Effective propagation velocities
As and Ar are Peak particle accelerations
In the design process emax = ±Vs/2Cs±AsR/C²s cos3q
The above formula is useful for calculating the curvature component under seismic forces. The tunnel design was based on key concepts of wave types and the mathematical relationships between longitudinal waves and curvatures deformations. Specific parameters for calculating sinusoidal thrust along a tunnel’s axis include the shear force with a wavelength-L, amplitude due to displacement D, and an angle of q wave type. On this basis, the forces due to wave motions with the potential to cause destruction on a tunnel due to earthquakes can be determined. The graph below illustrates the behavior of the forces (Channel tunnel 40)
This graph illustrates earthquake magnitude scales.
Types of Tunnel Design
This analysis narrows down to two design types. Channel tunnel construction was to overcome a specific problem or obstacle. These obstacles included water, a mountain, etc. Since tunnels provide a safer, faster and more efficient form of transportation, their design is an engineering challenge. Engineers must plan well by conducting a geological analysis of the ground to look at the risks involved. An analysis of the construction materials is done and the construction is based on developed plan. According to the findings two types of designs were compared. These included:
A Circular design and
A Rectangular design
In addition forces acting on rectangular and circular tunnels were considered in the design. According to the engineers conducting the analysis, a circular tunnel could experience an ovaling deformation on a shear wave front and a racking deformation on a tunnel with a rectangular cross-sectional area as illustrated below.
Appropriate data was obtained based on tests and analysis conducted on these design models. Rectangular tunnels have the disadvantage of space utilization compared to circular tunnels (Channel Tunnel 45).
Design Procedure for Tunnel Construction
The procedure for designing a tunnel for construction is based on data collected after identifying the necessary alignments, functional requirements, conducting a geotechnical analysis and various technical aspects of tunnel design in hard and soft rocks besides conducting an analysis of the forces due to earth loads, the design criteria, cultural and environmental issues, conducting a feasibility study and risk analysis, and documenting all the necessary available data. This was followed by an analysis of available construction methods and tools and evaluation of the best alternatives. According to the The institute of civil engineers (1993), other factors considered included the drainage system for the tunnel and lining requirements. Safety measures, ventilation requirements, and lighting requirements were incorporated in the design. Gradually of importance were the maintenance procedures for the tunnel. A tunnel must remain serviceable once it has been commissioned for use.
Specific procedures included determining the soils, rocks, and other parametric considerations including the Q-value of rock mass, span or height, spacing of bolts, and the thickness of shotcrete (Zhao, Shirlaw & Krishman 2000, p. 300). According to Zhao, Shirlaw and Krishman (2000), Q-value mass constitutes the quality of the rock mass under consideration, while other requirements fall under a rock’s support sub-system. The support of these rocks is solidly based on five principles among them being a matrix coding component based on the cause effect component, an expert system which explains cause, effect, and results (Zhao, Shirlaw & Krishman 2000). The final equilibrium to be established a dynamic simulating component fed into a Hopfield network in tunnel design is factored with a database (Zhao, Shirlaw & Krishman, 2000, p. 310).
Once all these information is in place, Zhao, Shirlaw and Krishman (2000) assert that the initial rock tunnel design can be conducted by analyzing and determining reinforcement measures for the tunnel, assessing the current design and making improvements, considering the behavior of the design in a variety of rock conditions. The interaction intensity can be monitored, and an assessment of the degree of the rock’s safety before commencing construction determined (Zhao, Shirlaw & Krishman 2000). In addition to these, a thorough analysis of the rock’s tensile strength and other rock properties should be conducted. In conducting a seismic analysis, two methods were considered. These included the ordinary seismic analysis and the Geotomography analysis.
Boring revealed the type of underground rocks. These led to the classification of rocks and seismic velocities. The ordinary seismic analysis revealed five velocity layers, which appeared to be parallel or lateral to the ground taking a convex shape. Data from seismic geotomography revealed seven layers with a boundary line of 3.2 km/sec a concave curvature. The study revealed a 3 complicated seismic 2.5 km/sec layer. Field reconnaissance also revealed some fresh outcrops of rocks (Zhao, Shirlaw & Krishman 2000).
Zhao, Shirlaw and Krishman (2000) have provided a detailed account of the type of tests conducted to determine the kind of earth movements the channel tunnel could be subjected to.
According to Channel tunnel designers, two types of deformations considered were axial and curvature types. Axial deformation, according to RUNNING LINE TUNNEL DESIGN (n.d) consisted of compression and tension forces acting on the tunnel.
Axial deformation: Illustrating of the behavior of tensional and compression forces along a tunnel.
Tunnel Construction Methods
Illustrates a Curvature deformation along a tunnel
Landscape topology determines the construction method used. The cut and cover method is a simple method for shallow tunnels mostly used in subway construction. A trench is excavated and roofed over. This method includes processes such as the conventional method in which a trench is excavated on the ground then covered with a load carrying support placed for supporting the covering material. Another term for the bottom up method is the caisson method. Here a drilling rig is used to insert walls on bedrock although soil is excavated a little distance ahead of a tunnel. Tunnel walls are then constructed from the foundation. Slab is laid on the floor after which side walls are erected. Once construction is complete, the subway roof is put in place. Different construction materials may be used for this including corrugated steel. Another method is the top down method. A trench on which the concrete wall is erected is prepared using a trench cutter. The slurry wall acts as a barrier to water seepage into the tunnel. The slurry wall is clay like mixture that laterally exerts hydraulic pressure to counter balance forces against the tunnel during excavation preventing it from collapsing. Bentonite and water form the raw products for the slurry. This stabilizes the excavation process by reversing the permeability of the tunnel’s soil.
The slurry can then be recycled and replaced with concrete after tunneling is completed. Castings are prepared using a form that takes the actual shape of the trench, and then the cast is waited to cure before it is removed. The subway is then restored after the after the trench has been filled.
The cut and cover method is significantly applicable in less congested areas and forms an inexpensive option to other methods of construction. The ground condition determines the technique used in the cut and cover methods.
Pipe-jacking
Specially made pipes are pushed into the soil using hydraulic jacks designed for the purpose. When working with this method, forces acting on the pipes, the ground, and the walls must be analyzed and manufacture recommendations for the equipments used on varying load conditions followed strictly. The loading process must factor the thrust and anchorage loads, kind of load transfers, and the interjacks. In the process, regular checks should be the routine with specific and cautious alignments of the equipments. Shield loads and total loads should be ascertained before commencing the work.
This method emphasizes on the use of mud slurry to stabilize the ground. In addition thrust estimates indicate that the muddy slurry plays a vital role in the pushing procedures. The significant benefit of this method is that it can be used in non disruptive constructions in overcrowded areas to mitigate problems associated with traffic and other forms of congestion. Pipes are pushed through bores made underground by a special machine referred to as drivage machine. Force is used to push and apply the thrusts necessary to penetrate the ground ahead of jacks. In more modern times, the use of circular pipes has been replaced with rectangular pipes. This has the advantage of efficient use of space.
Full faced
In this method excavation is done in a combination. That implies that it is a single operation. Rolling cutters mounted on a tunnel boring machine (TBM) apply thrust with a high speed spinning head on the tunnel crushing any rocks on them. Perforation of the workforce in the drilling process extends up to 5 meters in depth of the drilling holes. Weakness zones are handled better with blasting and use of conventional drilling techniques. This method reduces ground displacements significantly. Tests done when using this technique include centrifugal modeling to determine effects of roof support and the effects of displacements while drilling.
Blasting
Another excavation method is blasting. This method is appropriate for hard rocks. This technique is an engineering tool that depends on the stability of a rock, and incorporates studies on rock fragmentation when an explosive charge has been detonated on it. Bedding planes and a rock’s tensile strength determine the amount of force required to cause sheer displacement within a rock. Gas pressure causes rock fragmentation during detonation assisted by dynamic stress from the explosion. It is important to determine particle flight velocity and trajectory during an explosion to avert risks associated with such an explosion. Interlocking within a rock can be drastically reduced in a detonation and this reduces as the depth of a rock increases.
It is important to control blasting damages resulting from detonations to significantly produce a clean pre-smoothing of walls in a tunnel. The technique combines a simultaneous detonation procedure with very closely arranged detonations. This technique creates a clean surface with minimized risks particularly of a rock’s structural stability. Indications show that underground blasting causes reduced impact on rock fracture being less than half a meter in depth. A normal blast and a pre-site blasting method produce different results and the pre-site blasting method seems to be of an advantage in tunnel construction. A detonation must be precisely designed to achieve optimal results. A wedge is used to create a void into which a blasted rock displaces itself on detonation. This involves carefully drilled holes charged with detonations set off with regular delays.
Blasting must be appropriately designed and controlled to reduce blasting damage. This calls for efficient communication on the part of those involved.
Fire setting
The surface of a hard rock of a tunnel wall is heated to a certain temperature then water is poured on it making it crack due to rapid expansion and contraction due to the cooling effect. Scaffolds are used for safe and risk free use of explosives. This process is repeatedly done for the overall tunnel length.
Top heading and bench method
This method involves the construction of a smaller tunnel known as a top heading on the crown of the tunnel top. Two methods provide the initial opening according to (Tatiya, 2005). These include a single heading and double heading methods. Tatiya (2005) describes the single permanent lining for the roof erected after a calotte has been driven in when the top head has been driven into place. The lining walls are finally constructed though it takes time for them to set. Excavation resumes once a gap has been created through which excavators can proceed with their work. This excavation takes place below the excavation head. This level is referred to as the bench. The excavation proceeds from either sides or faces of the tunnel. (Tatiya 2005, p. 300) asserts that the second method consists of top heading and bottom heading. Both headings are driven concurrently followed by work on calotte and roof lining done gradually. Muck can be handled independently using this method. The top of the tunnel may consist of rocky soil or soft rock. Tatiya (2005) concludes that this method has the significant advantage in which it allows engineers to determine rock and wall stability as work progresses. This method allows tunneling to be done from both ends of the tunnel particularly when the tunnel is long and passes undersea. For enlargement purposes, the top part is used and this method has wide acceptance and use.
Potential Problems in Tunnel Design
Engineers face formidable challenges and constraints in tunnel design and construction. According to Tatiya (2005) these range from surrounding structures such as buildings, bridges, and other structures that may be affected by the construction procedures. Lateral forces due to tectonic movements of the earth, earthquakes and other strong vibrations majorly due to inertia of land masses. Large displacements of the ground and ground failures due to weaknesses in structural form, lateral forces, vertical forces, pressure vaults, and severe ruptures present another problem on these tunnels. Soil may mix with water to make a muddy mixture in the face of seismic vibrations forming a combined force that could crush a tunnel. In addition severe ground shaking may thoroughly damage a tunnel.
Racking of tunnels is another potential problem. Seismic forces may cause displacements leading to severe damages particularly for transportation systems such as roads or rail links running underground. Challenges and problems exist for tunnel construction in hard and soft rocks. Soft grounds may include clay and sand. Gravel, mud, and silt constitute soft grounds. The stand up time for this ground is short and engineering requirements dictate the use of a shield to avoid cave-inns. This steel structure is thrust into the ground. This structure creates a perfectly circular penetration on the soft ground in the construction process allowing workers to position precast concrete linings as they remove debris as a result of tunneling.
Other problems which may result from land forces include deformations such as axial, ovaling, curvature, and racking deformations for circular tunnels. When an oblique seismic force is applied on a tunnel, a curvature deformation may form on a tunnel in a linear or lateral direction. This horizontal deformation is also common with an axial deformation. A look at ovaling deformations, ground stability, ground conditions, and faulting provides a clear view on the effect of such problems on the design and construction of tunnels among others.
Ovaling deformation
Ovaling deformation also referred to as racking deformation results when the direction of wave movement is vertical, oblique, or lateral to the tunnel’s axis. This may cause a distortion or deformation of the tunnel lining when considering it from its end elevation. These deformations may act on a circular or rectangular tunnel. On both tunnels, the seismic force is predominantly due to the earth’s load and any designer must be critical when designing a tunnel based on these facts. The earth load’s factors’ predominance in this design over oval forces is partly due to:
Earth or ground movements in the vertical direction which causes less thrust on a tunnel compared to lateral movements which cause severe distortions. These movements account for only 1/3 or 2/3 of the horizontal movements. Shear forces in the vertical direction cause horizontal movements or vibrations. For overriding rocks, the vertical thrusts may be more drastic than horizontal ones in magnitude. These localized vibrations attenuate quickly from the point of origin.
An amplified propagation is possible for tunnels embedded in soft ground thus making vibrations more vigorously lateral. These wave propagations in the horizontal direction causes severe pull and push strains on rocks below a tunnel. In the design process, it has been proven that the resulting figures vary widely from those calculations based on soft ground compared to hard surfaces.
Ground stability. Soil can easily liquefy thus easily prone to landslides.
Faults may adversely damage a tunnel including tectonic movements in the lateral and vertical directions.
Ground conditions such as stiffness or overall strength in overcoming forces or thrusts due to earth load may vary drastically.
Ground stability
When designing a tunnel it’s worthwhile to consider the ground stabilization elements by incorporating design features and measures to curb drainages, reinforcements, and the manner in which earth load is retained. Soils provide real challenges in its removal and replacement. An unstable ground may present problems that may even stall a tunnel’s construction.
Faults
These may present design challenges if the possibility of avoiding them in the construction process is nil. To accommodate them a design scheme should be provided with appropriate materials to withstand dynamic and static loads due to faulting movements. In addition to that, the actual location of a fault should be identified and the design fault displacement determined. These certainties drastically reduce associated costs. When stresses on specific materials are stronger than the ability to withstand those stresses, a fault occurs.
Ground conditions
Ground changes is due to factors such as the ductility and rigidity of connections, tunnel junctions, ventilations at the end connections of a tunnel, the drastic variation in stiffness of different land masses a tunnel crosses, local restraints of tunnel movements, and flexible and movable joints on tunnels. Contrasting movements apply varying loads on a tunnel when subjected to these varied conditions. Differential data obtained as a result of calculations done on these movements determine the kind of joints to design for a tunnel.
Engineering equipments
According to () eleven boring machines dug through the tunnel characterized by chalk marl from either sides of the tunnel terminals at cheriton and Coquelles. The tunnel boring equipments consisted of tunnel boring machines through various soil and rock types. Tunnel boring machines (TBM) are designed to bore through hard and soft rocks besides boring through sand. Harris (1996) asserts that the machines are designed to cause minimal disturbance to the surrounding grounds and ensue walls’ stability. The resulting tunnel is smooth in nature with minimum distortions to the surrounding walls. Challenges such as lining and walls’ stabilities are minimized in the process, a vital element in the use of these machines. Though TBM’s are difficulty to construct and transport, they are also very expensive to construct.
Basically a TBM machine is designed with a fast rotating head on which is mounted a cutting head that crushes ground as drilling advances. The machine cuts a wall when supported by hydraulic jacks which provide the required thrust. Different TBM’s are used on different geological grounds. TBM’s are designed for both soft and hard rocks. Two types of TBM’s are used for hard rocks. These include the open type boring machine which is supported during the drilling process with rocks chewed from the cutterhead. A gripper provides support for advancing in the drilling process. The forward thrust depends on the gripper’s shoes acting against the walls. Boring takes place in intervals. At the end of a drilling interval, referred to as a stroke, the gripper assembly is prepared for the next interval of drilling by relaxing and repositioning the gripper’s rear legs by extending them to start drilling again.
Site investigation
With limited geological knowledge at the time the channel tunnel was proposed, years of investigations revealed a valuable body of knowledge that guided the tunnel’s design and construction. Significantly seismic profiling from data on off-shore and land geological surveys was conducted to determine geological strata along the construction line. Off shore geological surveys included the sea floor of Dover straights. This is a 60 meter long deep sea bed of strait consisting of synclines and anticlines with basement outcrops at various points such as that at Marquise. The UK strait is of undisturbed less deformed basin than the French side.
Chalk forms part of the tunnel rising and dipping at varying degrees with an emerging flat sea bed. The structural geology of the tunnel was based on tectonic sedimentation at various points with varying thickness of chalk. There is rich evidence of compression and tensional effects along the line with deformations occurring at different points. The data provided evidence of seismic movements along the tunnel line.
A survey of the tunnel line indicated joints at different points varying in dip with joints and disjoints witnessed along the line. Other major challenges encountered during construction included regional ground water, minor acqiclide at the UK side and slab failures in the construction process.
Requirements for construction purposes were determined. Site investigation provided vital data for determining the cost and engineering equipments to use. According to Harris (1996) a site investigation and geological survey was conducted to identify the rock types and determine other geological factors for the construction process.
According to Harris (1996) the tunnel site had been investigated close to 170 years. This lead-in time clearly illustrates the intensity and exhaustive nature of the investigation. Harris (1996) indicates that more than 100 holes had been sank to conduct underground investigations despite the close to half a million pounds cost for each hole sunk along the tunnel line or close to it.
Chalk forms part of the tunnel which rises and dips at different levels. The channel tunnel line consisted of seronian chalks, flint, turonian chalk, cenomanian chalk with varying thickness with low permeability and water flow in the direction of fissures.
Some of the investigations conducted included ground motion hazard analysis. According to the Technical Manual for Design and Construction of Road Tunnels – Civil Elements In this analysis (2009, p.1) “The process by which design ground motion parameters are established for a seismic analysis is termed the seismic hazard analysis”. This analysis according to the manual was conducted to determine the projections of seismic points capable of causing severe movements in the site of the tunnel, determine the strength of the seismic point or source, and identify how intense and strong the ground design could be. The geographic location of the tunnel was determined which provided information on the depths of the faults characteristics of the seismic source. The ground movements vary in intensity. It was determined that the motion intensity be identified based on varying complexity rating. These included, existing hazard analysis, deterministic hazard level analysis, and ground motion parameters.
Existing hazard analysis
This analysis provides information on spectral acceleration values depending on site locations, earthquake levels, and other developments. This depends on available and published information.
Deterministic hazard level analysis
According to the Technical Manual for Design and Construction of Road Tunnels – Civil Elements (2009), maximum values assigned to seismic sources are used for each point or source then the design earthquake is evaluated form calculations based on the vibration intensity to determine the level of damage that can be caused by the seismic shaking. To carry out this study, a seismologist must identify the location of the fault formation, determine the attenuation level in relation to ground motion parameters, the behavior of the earth load in the motion in relation to source and distances involved, and identify the sources of the seismic motions based on the seismic motion hazard. This method is valuable for cases that have damaging effects (worst case analysis).
Other analyses conducted include probabilistic analysis approaches where highest and lowest values of seismic forces are identified, the magnitude of the earth’s movements, and then a probabilistic value determined. This value provides information on the strength of a seismic source movement.
Ground motion parameter
These parameters are important in determining the peak ground velocities and displacements to analyze the potential damages that can be caused by earth displacements. PGA can be used to determine attenuation due to ground movements. According to the Technical Manual for Design and Construction of Road Tunnels – Civil _Elements (2009), the following formula can be used in design process as there is a strong correlation of strong motion data:
PGA = 0.394×10²(raise this to power 0.434c)
Where c= 4.82+2.16log S1=.0013[2.3logS1+2.93]2
Geological mapping
The channel tunnel as a case study provided useful information on the geological map to determine and enumerate the requirements in design and construction. According to the findings, it had been established that the ground contained no major fault along the line of construction. According to Price and Freitas (2009), the geological survey clearly indicated continuous rock strata on both sides of the proposed site. Sedimentation created a deposit of strata made of Gray chalk, Chalk marl, Glauconitic, and Gault Clay. Chalk marl was identified to form a 25-30 meter layer with a percentage of clay in the range of 30-40%, with glauconitic marl impressed between chalk and gault clay in this sedimentation process. The percentage in content of clay prevents ground water from seeping into the tunnel in the construction process. A slight variation is noted in the English side. The dip varies from 5 degrees in the English side to 20 degrees in the French side. Faults and joints with varying magnitude are in both sides of the tunnel.
The geological profile of the tunnel
To accurately determine the profile various costly bores were sunk at regular hard clay, thus making it brittle and more likely to be fractured. Harris (1996) the survey did not reveal any intervals to determine the nature of the rocks and soils in the site and other geological aspects. Harris (1996) repots that the both sides had faults though they were minor, they could not impede the commencement of the construction process. Faults varied in size in the range of two meters. The faults from both sides were identified to contain a clay substance known as pyrite that contained calcite and was limited in size. Harris (1996) noted that microfossil assemblage provided a clear distinction in determining and differentiating the types of clay. A study conducted on both coasts was able to determine that the French coast had more geological hazards to impede the commencement of tunnel construction. It was determined to be ideal to locate the English terminal at Castle Hill landslip. Buttressing provided stabilizing elements when drainage adits were inserted
Rock testing
Phases to conduct rock measurement surveys for channel tunnel were took place on both sides of channel tunnel. According to Harris (1996), the methodology had experienced successive developments and was finally accepted in 1988. It consisted of a geophysical survey 1.5 kilometers within the tunnel’s alignment and separated by a distance of 800 m. Calibrations were done on the Geophysical Survey Microfix and Syledis navigation systems before being installed. According to Harris (1996), these provided a 3.12 range of accuracy on shorts at close intervals. Results indicated well functioning systems. A large amount of data was collected and made available for use.
The machines’ abilities to cut through rocks could determine the kind of machines used in boring. This could help engineers ensue maximum utility and productivity. The engineers collected a variety of soils and rocks and subjected them to geotechnical laboratory analysis with definite testing procedures. The physical properties tested in the soil and rock samples included, density, unconfined comprehensive properties on a 600 KN machine, the tensile strength of the soil and rock on a Brazilian scaled machine, static elastic modulus, and modulus of deformation. The modulus of elasticity (E) is calculated using the linear part of the curvature of a deformation (illustrated above), which depends on the maximum deformations and peak forces on the curvature of the deformation. Plasticity of a rock or soil is determined using young’s modulus of elasticity and the modulus of deformation. The ratio of the maximum deformation value to the specimen’s primary length is calculated to determine the value of fracture deformation.
According to Singh and Goel (1999), the tensile strength and compressive strength of a rock are determined to identify the actual roughness of a rock or soil sample. This behavior is measured on a scale which indicates relative toughness. A value of 9 on the scale indicates tough behavior, while in the range of 9 and 15 is an average value and a scale of 15 indicates brittle properties. Further soil and rock properties include normal tensile strengths and parallel bedding planes. This description is based on the ability of a machine to cut through rock or a rock’s cut ability. The calculated ratio varies from one upwards.
Another test is the Schmidt rebound hammer. This test provides data on the strength required cause rebounds. The higher the strength of a rock the lower the value obtained. This test is particularly suitable for those rocks with higher values of hardness. The test procedure follows a ten times knock on the test hammer and the properties of the resulting crater measured.
Other tests conducted on rocks included:
Index tests. These tests are for determining rock cut ability which determines how well a machine will work in cutting specific rocks. It helps identify the best machines to use in the cutting processes. The basic reasons for these tests depend on differing values of shear strengths and the modulus of elasticity which determines plastic properties of a rock. Load applications on a test sample yield different values based on the cutting speed of a cutting head similar to that yielded on a cutter head. In the cutting process, the experience of the person handling the machine, the homogeneity of a rock, longitudinal and transverse inclination of the cutting head and rough profiling determine the cutting results. The relationship, the cutting rate (L), motor power (N), and the depth of cut or penetration (S) are represented by the equation: L= 0.075. S. N. Once the correlation coefficient has been determined, forces such as uniaxial compressive strength are determined.
The abrasive value of a rock is another property to test. This relies on the coefficient of wear. Using a polarizing microscope, the coefficient is determined along the following lines. Mineral or rock concentrations which may include substances such as carbonates, silicates, polymeric mineral grains, Mica, among others. The coefficient of wear is then calculated based on this formula: F= (V*d*t)/100 where V is the proportion of other minerals expressed as a percentage, d is the diameter of the test particle, and is the tensile strength of the test sample on the Mpa scale.
Other tests include the intensity of bonds within a rock and between rocks, rock homogeneity, solidification factors, and metamorphic transformations.
Stress Measurement Surveys
According to Amadei and Stephansson (1997), a number of methods were used to conduct rock measurement surveys. Indirect methods provided a means for determining stress in a rock’s body. Amadei and Stephansson (1997) clearly contend that measuring a rock’s stress is near impossible and this property can only be deduced for the whole rock body. The seismologists used six independent methods in analyzing the rock’s behavior. These included hydraulic methods which constitute hydraulic fracturing, the relief method which incorporates surface relief methods, underscoring, overcoring, and relief of large rock volumes. According to Stephansson (), other methods included the jacking method which constitutes the flat jack method, strain recovery method consisting of inelastic strain recovery, differential strain curve analysis, and the borehole breakout method.
From the above discussion it was noted that 100 bores had been sank along and some besides the tunnel trajectory. To determine the ground properties of the rocks where bores had been sunk different methods already mentioned above were used. One such method was the hydraulic method.
Hydraulic method
Amadei and Stephansson (1997), discusses this method as a composition of the fracturing method, sleeve fracturing, hydraulic fracturing and hydraulic testing on pre-existing fractures (Amadei & Stephansson 1997 ). Vertical and horizontal stresses play the principal role in determining the amount of stress that a rock can withstand. Vertical stresses are due to the earth load. This crack occurs due to a thrust by water on the rock that causes the rock to crack and tele-viewers provide information on vertical and horizontal fractures. Pressure time record is used to determine the horizontal stress components.
Picture illustrating the sinking of a bore
Some of the most well known tunnels
These include the Thames tunnel build under the Thames River, the Frejus tunnel under mount Frejus, the Seikan tunnel which happens to be the longest tunnel in the world connecting Hokkado and Honshu in Japan, and the Hoosac tunnel under mount Hoosac among many others.
Future Plans
Design and construction of underground tunnels is an engineering challenge that requires engineers to conduct detailed research on various aspects. In addition this requires a detailed body of knowledge, analytical data and detailed study and analysis of available information on tunnel design and construction. The above report majorly looks at the theoretical technical aspects and principles and their application on practical field on the topic. Of importance therefore is to look at design and roofing of tunnels as an important component in tunnel support. In addition to the study of the properties of materials used for roof support, the plan could incorporate aspects of cost and cost effective production of modern materials for roofing.
Detailed Research
From the above discussion, the researcher will concentrate in identifying cost effective modern engineering materials for tunnel roofing. In essence, the research will cover engineering properties of roofing materials, types of roofing materials including the cost of production of those materials using modern methods of materials technologies.
Research Topic
Each phase of tunnel design and construction constitutes wall supporting requirements as a dominant factor too ensue safety in the face of seismic vibrations, and other underground conditions. Engineers must consider the appropriate use of support as a measure of safety for the users of the tunnel. Typically, the properties of the materials particularly their strengths, installation and cost are of paramount importance. Therefore the research topic could be “Tunnel Roofing Materials”.
Conclusion
Tunnel design and construction is a challenging undertaking in the civil engineering field. Basic considerations on design and construction of these tunnels provide formidable challenges to overcome. Engineers must conduct detailed surveys and critical analysis of available and obtained data, conduct tests on the mechanical properties of soft and hard rocks to determine engineering requirements in the design and construction process. Seismic movements, wave motions and pressure due to earth loads, particle velocities and accelerations of underground soils and rocks due to deformation forces forms a fundamental part in analyzing a tunnel’s stability and construction methods. However, there is need to adapt modern cost effective engineering methods, material testing techniques, and adopt less costly methods and materials in tunnel construction. In addition there is need to conduct further research on roofing materials and identify the best and less costly modern materials for roofing tunnels.
References
Amadei, B., Stephansson, O., 1997. Rock stress and its measurement. Web.
Harris, C.S., 1996. Engineering geology of the Channel Tunnel [online]. Web.
Price, G. P., Freitas, de M., 2009. Engineering geology: principles and practice [online]. Web.
RUNNING LINE TUNNEL DESIGN, n.d. [online]. Web.
Singh, B., & Goel, R.K., 1999. Rock Mass Classification: A Practical Approach in Civil Engineering [online]. Web.
Tatiya R. R., 2005. Surface and underground excavations: methods, techniques and equipment [online]. Web.
Technical Manual for Design and Construction of Road Tunnels – Civil Elements , viewed, (n.d). [Online]. Web.
The institute of civil engineers, 1993. The channel tunnel: Terminal, part 2 [online]. Web.
Zhao,J., Shirlaw, JN, Krishnan, R., 2000. Tunnels and underground structures: proceedings of the International [online]. Web.
End elevation of tunnel channel (Eurotunnel schema)“Road tunnel type selection process”
The main role of unions is to protect the rights of the employees and to make sure that they are not exploited for the sake of profits. Unions can also influence the workers to strike for the sake of environmental conservation, resulting from substandard construction from subcontracting as a way of reducing costs. In a place like Melbourne, there may be a problem because the place is developed and the unions can influence the construction workers to strike for environmental purposes. The unions had succeeded first in Australia in holding strikes to conserve the environment so that it may not be reduced to a financial speculation city and risk losing its value and beauty (Burgmann & Verity 1998 p. 47). This is a concern where the unions may not favor construction for the sake of the environment. Again, the fact that the people to be employed in construction sites may be exploited in terms of remuneration inequality and job insecurity there may be problems with the union (Bosch & Peter, 2003 p.134).
Discussion
In Australia, there was a demonstration concerning the construction of high-rise buildings which was termed as a mistake. The authorization of many bad projects in the name of job creation, which was as a result of corrupt officials, was the main concern. The labor unions resulted in mobilizing the followers to strike to conserve the environment and maintain the beauty of the cities in Australia, and at the same time avoid the chances of being exploited financially in their remuneration. For construction to carry on without a lot of interference, or without any at all, it would be necessary for the construction management to have sound and convincing reasons to support the development of high-rise buildings in places like Melbourne, Australia.
For the construction of about thirty stories to go on without much interference from the unions, then the constructor must be able to show a significant benefit to the economy, in terms of stable employment that surpasses the setback of exploitation as many construction workers in Australia are now under union (Bosch & Peter 2003, p.133). The contractor has to show the overall benefit of the construction and the adherence to the standard rates of remuneration to the construction workers. This would be by way of avoiding subcontracting, which aims at reducing cost, thereby victimizing the employees by paying them poorly relative to the amount of work they do.
Secondly, the contractor must come up with direct action solutions. These solutions must be appealing to the idealists and activists who may bring down the whole process by influencing the employees to strike thereby leaving the construction work (Burgmann & Verity 1998, p. 289). Solutions to address the issue of job insecurity and discrimination on the remuneration of the construction employees must be provided. This will send a positive gesture to the union and therefore, there will be less or no interference from it. This will mean that the construction will proceed smoothly.
Thirdly, the constructor, in Melbourne, must show the environmentalists the overall benefits of the construction and that it is in no way an environmental threat so that the union will not mobilize its followers who work for the construction, to strike and make it difficult to continue with the construction process (Burgmann & Verity 1998, p.290). In Melbourne, one of the main setbacks for the construction industry is the fact that they are associated with environmental degradation, where the city would result be a place of financial speculation rather than a place for the people and beauty. This would contribute negatively by leading the union lobbying campaigns and initiating strikes because the purpose of construction is for-profit reasons by the construction company(s) (Burgmann & Verity 1998, p.290).
Fourthly, the construction manager should devise strategies of increased worker participation in the construction (Langford, Robert & Sydney 2002, p. 67). This leads to the workers being actively involved in the work and the trade unions respect the gesture and they use it as a partnership for the benefit of both the workers and the employers in the construction industry. In a place like Melbourne where the history of construction workers’ discrimination is based on poor pay and job security, it would be advisable for the manager to involve the workers in active participation of the construction work and process so that they may be assured of their job security. This would go well with the union because they would not have to worry about losing the jobs of their workers.
The construction process in Melbourne, Australia, is faced with two major challenges, the construction worker welfare, and the environmental challenge. These two challenges must be adequately addressed for the construction to go on without interference from the union. With good remuneration, job security to employees, and good environmental intentions, the construction work will go on without interference from the union, even though it is a thirty story building, for our case.
Reference List
Bosch, G., & Peter, P., 2003, Building Chaos: an international comparison of deregulation in the construction industry. London: Routledge.
Burgmann, M. & Verity, B., 1998, Green Bans, Red Union: Environmental activism and the New South Wales. Sydney: UNSW Press.
Langford, D., Robert, N. & Sydney, U., 2002, Construction Management in Practice. New York: Wiley-Blackwell.