Safely Dismantling Structures

Introduction and Background

Every engineering structure has a definite design life, which can range from 10 to even 100 years or more (Gehl, 2011). When this life span is surpassed, the structure may no longer be safe for human occupation and the adjacent structures. This is when demolition of the structure is carried out to free the space for other developments. Demolition can also be carried out to replace small structures with bigger ones. This is commonplace in old towns where lowrise structures are continuously replaced with highrise structures as a result of population surge. In other instances, a given building may experience some degree of structural damage, say due to a blast or fire or excessive loading, and therefore be rendered unsafe for the intended use.

Demolition ideally entails breaking down or removal of the components that tie the structure together (The demolition of structures, 2001). It is usually a delicate process given that other structures and human activities exist around the structure marked for demolition. For this reason, demolition needs to be approached in four distinct stages.

The first step involves a thorough survey of the building (White and Kelly, 2006). First, the types of construction material used are identified - steel, timber, masonry blocks, concrete blocks. Then, the uses of the building since construction are identified. This helps identify the presence of any hazardous materials within and around the building. Drainage conditions around the building are then assessed to predict whether demolition of the building is likely to cause erosion, flooding or water pollution. Additionally, a survey is done to determine what facilities are shared between the building under demolition and the adjacent buildings. It is commonplace to find neighbouring buildings sharing structures such as staircases, partition walls and skyways. A building may also be connected to some tunnel, road or driveway. Another consideration is the neighbourhood, specifically how it will be affected by noise, dust, and vibrations, which are common in any demolition process. The structural engineers go further to examining the method of construction. A concrete framed building is structurally not the same as a building with load-bearing walls. Similarly, a building put together using precast structural elements cannot be treated in like manner to a building which was mostly cast in situ.

Once a detailed assessment of the building is done, hazardous materials are the first to be removed from the building (Winkler, 2010). This is for the obvious reason that such materials can cause serious health effects as the demolition crew proceeds with its job. The most notable hazardous material in construction is asbestos. This has long been used in buildings for fireproofing. Asbestos is mostly applied on steel beams and columns, and also concrete, asphalt, vinyl materials, roof shingles, pipes, siding, wall board, floor tiles, joint compounds and adhesives, due to its strength characteristics. When asbestos is damaged or crumbles, asbestos fibers get released into the air and this poses serious health problems to anyone in the vicinity. Other hazardous materials likely to be found in buildings include petroleum contamination, radioactive metals, lead, mercury, polychlorinated biphenyls (PCB), and chlorofluorocarbons. These require the employment of professionals for safe removal.

The next step is preparing a detailed demolition plan for the building and the individual structures that make up the building. The distances between the structure under demolition and adjacent structures is accurately measured and engineering calculations computed to analyse the safety of the structures to be left intact (Strandholdt Bach, 2019). The structural support system of the building is also assessed so as to determine the best way to bring down the building without accidents. The methods by which the building debris will be handled are also proposed. The precautionary measure to be taken to ensure the safety of the demolition crew, other humans and other structures are defined. The outlined methods and measures are then followed to the letter during the actual demolition process.

Although the process seems straightforward, demolition has been one of the most challenging activities in the construction industry (Higashi and Isobe, 2017). For small buildings like bungalows and maisonettes, the demolition process is not overly complicated since a combination of hydraulic equipment on some raised platform is enough to complete the job. The real problem comes in when large buildings have to be demolished. Hydraulic equipment may not be of much use since they all have a limited height they can reach. The use of other methods such as wrecking balls and implosions is then considered.

In their journal titled Deconstruction, demolition and destruction, Thomsen, Scultmann and Kohler (2011) assert that governance has the most significant influence on demolition. Governance is herein defined as the regime made up of an intricate set of legal, financial, commercial and operational rules, drivers and barriers. Initially, towns took the organic route in their redevelopment. However, over the last 100 years, mass construction and large scale ownership of property gave rise to what they refer to as the stop-and-go development cycle. Unlike the past, the renewal of settlement nowadays greatly depends on regional market conditions and property ownership. As a matter of fact, it is very seldom to find owner-occupied houses being demolished. Demolition is however rampant when it comes to the rental houses. The three further argue that demolition is chiefly informed by obsolescence, where obsolescence translates to loss of prestige and value. According to them, demolition is no longer an organic process as it used to be some years back. Public policies play quite a big role in the demolition of structures, although many find it difficult to comprehend these policies.They finally call for deeper exploration of the demolition question, the results of which should be used to inform policy, strategy, and practice.

This is because of the numerous questions about demolition that remain unanswered today. Some of the questions include: What exactly are the theoretical and real life structural and economic spans of structures? What demolition rate can be categorized as normal? What is the mean life span of buildings in other countries and why does it defer from this country? What are the actual demolition motives of the different stakeholders in any given property? How is the social impact of demolition evaluated? How does governance influence the process of demolition? How does the design of structures influence their economic life? Is there a way to determine the value of a building marked for demolition? Does the valuation process include the immaterial elements such as residents’ emotion and cultural heritage? (Thomsen, Schultmann and Kohler, 2011).

Several demolition projects in the course of history have proven the delicate nature of the activity. The demolition of the 53-metre high brick chimney at Briggate, Leeds is a living example of how complex demolitions can turn out. Communication and coordination took place under extremely high pressure enough to cause anyone to burn out. The use of explosives for the tall structure also posed quite some danger on the surrounding structures. During the demolition of the Mad River Power Plant in Ohio, the demolition crew allegedly forgot to cut some reinforcement bars along the base of the tower. When the explosives went off, the structure fell in the opposite direction and damaged a major power line, leaving thousands in the dark. Other notable demolitions that went wrong include the Pontiac Silverdome in Detroit, the storage tower in Redbank, Australia, and the Zip Feed Mill Tower in Sioux Falls, South Dakota. Present and future demolition undertakings should be well prepared to circumvent such technical constraints (Limer, 2017).

Research Aim and Objectives

The main objective of this research is to explore the legal, technical, planning and safety constraints experienced in a live demolition project in understanding their impact on the chosen demolition methodology and programme. To achieve this goal, the demolition project of the cooling towers at Ironbridge Power Station will be used as a case study. The following are the specific objectives of the research:

To identify typical technical challenges in a live demolition project

To explore the problem solving approach by relevant authorities to the typical technical challenges faced during demolition.

To investigate the positive and negative implications of legislation regarding demolition

To explore the differing views between different stakeholders in a typical demolition project

Proposed Methodology

For the purpose of this research, the Iron Bridge Power station will be used for the case study.

Research setting

Ironbridge Power Station is located on the banks of River Severn in Shropshire, England. It was back in 1927 that the Electricity Authority of that time identified the area as suitable for power generation. The river waters would be used for cooling purposes while the connecting railway lines would be used for transportation of coal to the site. The presence of flat land across the area was also seen as very suitable for setting up the large turbina hall. The construction took place in 2 major phases. Ironbridge A came to completion in 1932. Electricity generation however began later in 1939 when all equipment was in place. The output then was about 200 MW. Further on, after the second world war, the Electricity Authority made the decision to set up Ironbridge B as a response to the increasing demand for electricity. The second station was set to produce 100 MW of electricity.

The power station was designed by architect Alan Clark and landscape specialist Kenneth booth to perfectly blend into the environment. It came out as one of the most unique coal power stations in the UK. The cooling towers form the main attraction in the area. The structure is primarily red-pigmented concrete. The use of coal for power generation got into strong criticism by environmentalists because of the high degree of pollution associated with it. The decision was made around 2012 to modify the station for use of biomass fuel. Having no use of the cooling towers, they were earmarked for demolition, amidst fierce protests by the locals who saw the structures as a great cultural heritage. The English Heritage did not find the concerns valid, and therefore the towers were demolished in December 2019. This forms a great case study for exploring the legal, technical, planning, and safety constraints experienced in a live demolition project.

Justifying the use of the case study for the research

Yin, Merriam and Stake (2015) discussed the three main conditions that make it justifiable to use the case study as a research tool. The first instance is when the nature of the question is typically exploratory. That applies to investigation of constraints involved in construction demolition. It would be rather impractical to explore such constraints through laboratory experiments. The most reasonable approach is to use a real life demolition project.

Secondly, case studies are appropriate where the researcher is not able to control the site and participants. Demolition involves quite a number of stakeholders, from the government, the local authorities, the environmental authorities, health and safety authorities, the local dwellers around the area of demolition, the current occupants of the structure to be demolished, Heritage bodies, and the lawmakers of the country among others. There is no practical way in which the investigator can have control over all these participants, thus justifying the use of the case study.

The third scenario is when the phenomenon under study is contemporary and the context is real life. Demolition challenges is a real life subject. One can’t explore the challenges unless the demolition is on course and constraints are being encountered. For these three reasons, the case study is an appropriate research tool for the investigation into the constraints faced during demolition exercises.

Data Collection Methods

Two basic methods will be used for collection of data for the current research.

1. Desktop Study

2. Detailed Questionnaire

Desktop study will be used for diagnostic investigation into the experiences, decisions and outcomes at Ironbridge Power Station. In the researcher’s possession are documents such as the methodology appraisals for the demolition, guidelines from the Environmental Protection Agency regarding removal of asbestos, regulatory legislation from local authorities regarding demolition of structures, and detailed technical designs of the power station. Secondary data is usually the first port of call in research. Actually no research should be done without first searching for existing secondary resources related to the study. It is cheaper to collect secondary data than primary data. In addition, secondary data helps the researcher to define the population. In this case, the researcher is able to know exactly the relevant persons he should interview and administer questionnaires to.

A detailed questionnaire will then be designed to be given out to a selection of the staff employed in all the organizations and companies that took part in the demolition exercise. Questionnaires are a handy tool in investigating the expectations and perspectives of different people. In such demolition exercises, every player definitely had expectations and these were either met or not met. Every participant also encountered some constraint, which may be different from the other one. Questionnaires also allow the researcher to contact a larger population sample at a fairly low cost. They also enable the researcher to save oon time since different respondents can fill the questionnaire simultaneously. They are also very effective when discussing sensitive topics which the participants may not feel comfortable sharing with the researcher. It may be to some a bit difficult to openly discuss the constraints faced for fear of victimisation.

To complement the questionnaires, direct interviews will be carried out, especially on the main stakeholders of the demolition exercise. These include the project managers, the senior representatives of the principal contractor, the chief designer, the client, staff from the Federation of Demolition Contractors, Institute of Explosive Engineers, and staff from the Institute of Demolition Engineers. This will give the researcher an in-depth understanding of the constraints faced during the demolition and the approach of the different stakeholders towards solving the challenges.

Scope, restraints and limitations

This research should ideally involve all stakeholders in the demolition exercise of the cooling towers of the Ironbridge Power Station. This includes both the employees working at the power station, the regulatory authorities and the contractor awarded the demolition contract. In addition, the local dwellers of the area around the power station will be asked to discuss their experiences during the demolition exercise.

The major limitation of this research is the fact that it is taking place when the entire world is struck by the deadly coronavirus pandemic. The viral disease has resulted into partial and total cessation of operations for many industries. As it is not yet clear when the restrictions will be relaxed, there is a great likelihood of failing to reach some of the key stakeholders scheduled for interviews. A lot of deaths have also occurred across the country and it may be that some of the demised hold critical information regarding the demolition project. If it be so, the researcher may be forced to make a few changes to the research design to accommodate new interviewees.

Another limitation may be the fact that some stakeholders would restrain from openly discussing the constraints faced as it may be seen as a form of failure on their part.

Expected outcomes or deliverables

From preliminary research into the general constraints that face demolition projects, a number of factors were found to recur from project to project, and it is expected that the current research will not deviate a lot from the previous findings. Outlined below are general constraints of similar demolition exercises:

The presence of a busy pedestrians street adjacent to the structure under demolition may slow down the exercise

Complying with the noise reduction regulations may not be practical, and therefore the demolition contractor may face the wrath of the neighbouring businesses and residents.

Adjacent structures which are not set to be demolished may end up being destroyed if the demolition does not go as planned

Maintaining the safety of the demolition crew may be challenging

The inherent danger of using explosives can never be underrated.

Communication and coordination may be under intense pressure and this may take a physical and mental toll on most of the workers.

After this research proposal, the next deliverable will be the preliminary research report with complete introduction, literature review, and research methodology. This should be submitted in about 2 months from now. Afterwards, the final dissertation report will be prepared, complete with the results, discussion, conclusions, recommendations, and raw data.

Research beneficiaries and dissemination

The findings of this research will be of great use to demolition contractors around the UK. Although it is expected that most of the contractors understand the challenges likely to be faced during demolition, not all of them have had first hand experience in demolishing structures over 100 m tall. This case study will help them comprehend the nature of such demolition exercises and be in a better position to handle such contracts if they are awarded in the future. The regulatory authorities will also find the research useful and may rethink the laws put in place regarding demolitions.

References

2001. The Demolition Of Structures. Sydney, N.S.W.: Standards Australia International.

Gehl, J., 2011. Life Between Buildings. Washington, DC: Island Press.

HIGASHI, K. and ISOBE, D., 2017. Study on Blast Demolition Planning of Buildings for Improving Efficiency of Demolition and Safety during Demolition. The Proceedings of The Computational Mechanics Conference, 2017.30(0), p.061.

Strandholdt Bach, J., 2019. Demolition Blues. Resistance Against Demolition Plans in a Danish Disadvantaged Affordable Housing Estate. Archivio antropologico mediterraneo, 21(2).

Thomsen, A., Schultmann, F. and Kohler, N., 2011. Deconstruction, demolition and destruction. Building Research & Information, 39(4), pp.327-332.

White, T. and Kelly, S., 2006. Demolish the Bad Restaurants. Books Ireland, (288), p.218.

Winkler, G., 2010. Recycling Construction & Demolition Waste. New York: McGraw-Hill.

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