Identifying Root Causes of Construction Accidents

Construction accident investigation techniques and reporting systems identify what type of accidents occur and how they occurred. Unfortunately, they do not properly address why the accident occurred by identifying possible root causes, which is only possible by complementing these techniques with theories of accident causation and theories of human error. The uniqueness of the construction industry dictates the need to tailor many of the contemporary accident causation models and human error theories. This paper presents an accident root causes tracing model (ARCTM) tailored to the needs of the construction industry. ARCTM proposes that accidents occur due to three root causes: (1) Failing to identify an unsafe condition that existed before an activity was started or that developed after an activity was started; (2) deciding to proceed with a work activity after the worker identifies an existing unsafe condition; and (3) deciding to act unsafe regardless of initial conditions of the work environment. In addition, ARCTM emphasizes the need to determine how unsafe conditions exist before or develop after an activity is started and proposes that these unsafe conditions are due to four causes: (1) Management actions∕inactions; (2) unsafe acts of worker or coworker; (3) non-human-related event(s); (4) an unsafe condition that is a natural part of the initial construction site conditions. Thus, ARCTM acknowledges the possible contribution of both management and labor to the accident process. This perspective helps in better explaining accidents on construction sites and in identifying areas where prevention efforts should be directed, so that labor and management may provide more effective measures for preventing accident occurrence.     

深基坑工程施工风险评估方法研究

深基坑工程是一个复杂的系统,其风险评估是当前岩土工程界的热点之一。基于模糊层次分析法,确定了深基坑工程项目施工风险评估的指标体系及其风险评估影响因子的相对权重;通过对深基坑施工风险发生概率及风险损失程度进行分级,结合实际深基坑事故损失量化特征,建立了深基坑施工风险接受度门槛值,确立了深基坑施工风险评估标准;基于风险矩阵定性与定量相结合的评价方法,确定深基坑施工风险评估模式。通过实际深基坑工程案例,判定了深基坑工程施工过程中各个风险因子的风险等级。验证了本文风险评估模式的有效性。     

Fatalities and injuries in the Kuwaiti construction industry

This paper presents an analysis of construction accidents in Kuwait along with accident causation and injuries that can be considered serious or fatal, so that corrective measures can be taken to decrease casualties, resulting in a safer construction industry. The paper evaluates the existing injury and cost reporting-investigation system of construction accidents in government agencies and private firms. This research confirms that construction is the most hazardous industry in Kuwait, with accidents accounting for 48%, 38% and 34% of all disabling injuries and 62%, 38% and 42% of all fatalities in 1994, 1995 and 1996, respectively. These rates are considered high and can be compared to construction accident statistics in the U.S.A. which accounted for 14% of all work-related deaths and 9% of disabling injuries in 1993. Based on the study, falling from a height appears to be the major cause of construction injuries and fatalities in Kuwait. Poor accident records and reporting systems hide the extent of the construction safety problem in Kuwait. In addition, many people at management level are unaware of accident-related costs and the effectiveness of a safety program in reducing project costs.     

The Nature of Struck-by Accidents

Construction accidents are broadly categorized into five basic groups, namely falls (from elevation), shock (electrical), caught in/between, struck-by, and other. “Struck-by” accidents accounted for 22% of all construction-related fatalities recorded by the Occupational Safety and Health Administration between 1985 and 1989. Recent (1997 to 2000) data show that the percentage of struck-by accidents constituted 24.6% of the fatalities and serious construction worker injuries. Struck-by accidents primarily involve workers struck by equipment, private vehicles, falling materials, vertically hoisted materials, horizontally transported materials, and trench cave ins. Determining possible causation factors of these accident types is often difficult, due to the broad categories utilized in the accident coding system. This study resulted in gaining insights about the root causes of the struck-by injuries. By finding the root causes, effective methods for accident prevention can be developed.     

Incident Causation Model for Improving Feedback of Safety Knowledge

In order for the construction industry to improve its poor safety performance it needs to learn from its mistakes and put the lessons learned to good use. This need calls for effective feedback mechanisms that can transmit information derived from incident investigation to be utilized in safety planning. The feedback should be at two levels; first, feedback to the Safety Management System that had failed, and second, feedback to the safety planning of future projects. The first level of feedback can be achieved by basing the investigation on an incident investigation model that explicitly identifies system failure. The second level of feedback can be achieved if both incident investigation and safety planning share the same incident causation model, such that the information from each process can be retrieved and utilized in the other process smoothly. One prerequisite to fulfill the two levels of feedback is the development of an incident causation model. In this paper, the modified loss causation model (MLCM), which is able to meet the above-mentioned purposes, will be presented. The MLCM is developed based on an extensive literature review and application on 140 actual accident cases obtained from Singapore’s Ministry of Manpower, Occupational Safety Department. In this paper, the model’s application will be demonstrated through a case study, which involves codification of investigation information based on an actual incident report, and a safety planning process based on a hypothetical case.     

Scheduling-Based Risk Estimation and Safety Planning for Construction Projects

This paper considers the issue of safety risks on construction sites. It introduces the concept of combined effect of different risk factors to the accident. For proper safety planning, safety managers need to be well aware of the direct causes of the accident as well as indirect factors that adversely effect on site safety. If it is observed that if a hazardous environment exists at the site, then either that hazardous environment must be eliminated or occupations and processes related to that hazard must be properly protected. One of the measures for evading such hazardous situations is to predict such situations and to reschedule the start time of high-risk situation so that risks are not concentrated during certain periods and at certain locations. In order to predict when and where the risk will reach its highest level, analysis should be performed based upon various information including statistical sources such as accident histories and this should be done in coordination with the activity scheduling. This paper analyzes the result of accident history and provides information about vulnerable situations. In addition, it presents a theory of safety planning method which estimates the risk distribution of a project and helps the safety manager to both estimate situations of concentrated risk and then to reschedule it when it is necessary.     

Benchmarking Studies on Construction Safety Management in China

This paper presents information by which to measure safety management performance on construction sites. In China, the conventional construction safety benchmarking approach is to assess safety performance by evaluating the physical safety conditions on site as well as the accident records, while no attention has been paid to the management factors that influence site safety. This paper is to identify the key factors that influence safety management and to develop a method for measuring safety management performance on construction sites. Based on the survey and interview data collected on safety management factors in 82 construction projects in China, the safety management index as a means to evaluate real-time safety management performance by measuring key management factors was developed. The quantified factors were compared with the commonly accepted physical safety performance index, which was derived from inspection records of physical safety conditions, accident rates, and the satisfaction of the project management team. Multifactor linear regression was conducted and the result indicates that safety management performance on site is closely related to organizational factors, economic factors, and factors related to the relationship between management and labor on site. Based on this benchmarking study, a practical safety assessment method was developed and then implemented on six construction projects. The results show that this method can be an effective tool to evaluate safety management on construction projects.     

Measuring Safety Climate of a Construction Company

Safety climate can benefit contractors, specialty contractors, and owners of industries by providing them with the knowledge of attitudes and perceptions that can help to consistently achieve better safety performance. The objective of this research was to determine safety climate that would enhance safety culture and positively impact perceived safety performance on construction projects. A safety climate questionnaire survey was conducted on the construction sites of a leading construction company and its subcontractors in Hong Kong. Approximately, 1,500 hard copy questionnaires were distributed and the response rate was excellent, resulting in 1,120 valid questionnaires being collected from 22 construction projects. By means of factor analysis, two underlying safety climate factors were extracted, accounting for 43.9% of the total variance. Multiple regression analysis confirmed that these climate factors, “management commitment and employee involvement” and “inappropriate safety procedure and work practices” were significant predictors of workers’ perceptions of safety performance. The findings indicated that the relationship between perceived safety performance and “inappropriate safety procedure and work practices” was inversely correlated. The results suggest that safety climate can be used as an effective measure of assessing and improving site safety for projects under construction. The findings of this study and the methodology might be useful for research at other construction sites in other regions and countries. This work provides useful information for project managers and safety practitioners who desire to improve safety climate and safety performance on construction sites.     

Design Error Classification, Causation, and Prevention in Construction Engineering

Construction and engineering practitioners have found it increasingly difficult to learn from their mistakes, particularly with regard to the prevention, identification and/or containment of design errors. Yet, design errors have been the root cause of numerous catastrophic accidents that have resulted in the death and injury of workers and members of the public. This paper examines and classifies the nature of error and design error causation in construction and engineering projects. A review of the normative literature revealed that design errors are caused by an array of factors that can work interdependently. A generic framework is developed that classifies design error according to people, the organization, and project is presented. The paper suggests that people, over and above organizational and project management strategies, have the greatest propensity to reduce errors through the process of situated learning and knowing. This is because the working environment provided by an organization and the processes used to deliver construction and engineering projects influence the nature and ability of people to undertake tasks. Consequently, there is no single but rather a multitude of strategies that need to be adopted in congruence to reduce design errors so that safety and project performance are ameliorated.     

Systematic Evaluation of Construction Equipment Alternatives: Case Study

Selecting the right equipment for the project is inherently a multifaceted cost and benefit evaluation process that is further compounded by the complexity of today’s building projects and the lack of systematic tools for the consideration of soft factors. This paper presents a detailed application example of a model based on an analytical hierarchy process (AHP) approach. This model was developed to address the difficulties experienced during the multifaceted process. The example illustrates how an AHP-based model helps address the multitude of qualitative, intangible factors, both among the factors themselves and then vis-à-vis costs, by means of a systematic and traceable process. The method enables project managers and their equipment selection teams to exercise their knowledge, intuition, and professional judgment, and at the same time to address the context and specifics of the particular projects under examination. The example should be helpful for construction practitioners dealing with similar equipment selection issues. Researchers may find interest in the implementation of a multiattribute-decision-making method for a typical construction management problem.     

Design and Construction Challenges of a Federal Laboratory Building: A Case Study

This paper presents a case study regarding design and construction challenges of a federal laboratory building. The case study illustrates the successful collaboration of two federal agencies, General Services Administration (GSA) and Centers for Disease Control and Prevention (CDC). Creative methods were used to resolve complex design, construction, and budgetary issues. This paper describes lessons learned from a specific laboratory project on issues such as: A master plan and its role in locating secure laboratory buildings, site planning issues, contracting mechanisms, building security, energy, project development, design and construction excellence, and funding. Although CDC and GSA approved the release of this paper, the authors offer a disclaimer that the opinions and conclusions drawn in the papers are those of the authors, and are not necessarily shared by the CDC and GSA.     

Applications of Horizontal Characterization Techniques in Trenchless Construction

Horizontal site characterization technologies present a rapidly evolving alternative to traditional vertical site investigation methods for subsurface investigations of large diameter trenchless construction projects. A state-of-the-art review of horizontal site characterization tools, both currently available and under development, is presented. Additionally, a rational methodology for the selection and deployment of horizontal site investigation techniques in trenchless construction projects is also presented. The methodology enables the user to define and quantify the risks involved in a particular project, as well as to evaluate the degree to which these risks can be mitigated using various site characterization techniques. The proposed model is demonstrated using a working example. The paper concludes with a discussion of future trends in this exciting new field. The main conclusions drawn from this work are (1) adequate subsurface information is invaluable for underground construction; (2) site investigation programs of linear construction projects can be enhanced by horizontal characterization techniques; and (3) the availability of continuous and near-continuous subsurface information enables the utilization of new approaches for the analysis and representation of subsurface data.     

AHP-Based Equipment Selection Model for Construction Projects

Selection of equipment for construction projects, a key factor in the success of the project, is a complex process. Current models offered by the literature fail to provide adequate solutions for two major issues: the systematic evaluation of soft factors, and the weighting of soft benefits in comparison with costs. This paper presents a selection model based on analytic hierarchy process (AHP), a multiattribute decision analysis method, with a view to providing solutions for these two issues. The model has the capacity to handle a great number of different criteria in a way that truly reflects the complex reality, to incorporate the context and unique conditions of the project, and to allow for manifestation of user experience and subjective perception. The model was implemented in an in-house developed system that was improved and validated through testing by senior professionals. The main academic contribution of the study is in the modification of AHP to correspond with the nature of equipment selection and in its utilization as an effective means for the formalization of knowledge possessed by competent, experienced practitioners. On the practical side, the proposed model offers an efficient, convenient tool that forces the users into orderly, methodical thinking, guides them in making logical, consistent decisions, and provides a facility for all necessary computations.     

Innovation in Construction Engineering Education Using Two Applications of Internet-Based Information Technology to Provide Real-Time Project Observations

Improvements in construction engineering education result when innovative information technologies are incorporated into academic curricula. Through the use of internet-based communication technologies, no longer must students physically travel to a construction project site to observe and hear construction operations. This paper discusses two applications of internet-based, audio and video technologies currently being piloted at Iowa State University (ISU) and at the University of Calgary (UC) for the purpose of bringing live construction projects into the university classroom. Virtual Project Tours have been piloted at Iowa State University in which real-time video and audio are delivered from active construction projects to a remote classroom through the internet. The second application discussed in this paper, Virtual Supervision, is being piloted at the University of Calgary and consists of the monitoring and analysis of construction projects by using imagery gathered by web-enabled, digital cameras of fixed location transmitting video through the internet. This paper also presents a vision of a globally networked organization of engineering and construction education institutions each sharing the unique engineering and building techniques of their respective part of the globe with design and construction students located around the world. This exchange of construction project observations among the institutions will be enabled by the internet-based applications of virtual project tours and virtual supervision systems described in this paper.     

Dynamic Prediction of Project Success Using Artificial Intelligence

The purpose of construction management is to successfully accomplish projects, which requires a continuous monitoring and control procedure. To dynamically predict project success, this research proposes an evolutionary project success prediction model (EPSPM). The model is developed based on a hybrid approach that fuses genetic algorithms (GAs), fuzzy logic (FL), and neural networks (NNs). In EPSPM, GAs are primarily used for optimization, FL for approximate reasoning, and NNs for input-output mapping. Furthermore, the model integrates the process of continuous assessment of project performance to dynamically select factors that influence project success. The validation results show that the proposed EPSPM, driven by a hybrid artificial intelligence technique, could be used as an intelligent decision support system, for project managers, to control projects in a real time base.     

Integrated Schedule and Cost Model for Repetitive Construction Process

Several efforts have been made by many researchers to develop a model for schedule and cost integration in construction projects, but it is difficult to integrate and manage schedule and cost in an actual construction site using such a model. The integrated schedule and cost model developed in this study (1) enables the planning and control of repetitive construction processes and (2) can be used by a project manager in an actual construction site. Furthermore, an integrated schedule and cost model for the core wall construction, which is an important repetitive process in the recently booming high-rise building construction in terms of scheduling, was developed using the integration model developed in this study. It is expected that the integrated schedule and cost model developed can allow project managers to integrate the schedule and cost of repetitive construction processes more effectively and support the project managers’ decision-making.     

Risk and Price in the Bidding Process of Contractors

Formal and analytical risk models prescribe how risk should be incorporated into construction bids. However, the actual process of how contractors and their clients negotiate and agree to price is complex and not clearly articulated in the literature. With participant observation, the entire tender process was shadowed in two leading U.K. construction firms. This was compared with propositions in analytical models, and significant differences were found. A total of 670?h of work observed in both firms revealed three stages of the bidding process. Bidding activities were categorized and their extent estimated as deskwork (32%), calculations (19%), meetings (14%), documents (13%), off-days (11%), conversations (7%), correspondence (3%), and travel (1%). Risk allowances of 1–2% were priced in some bids, and three tiers of risk apportionment in bids were identified. However, priced risks may be excluded from the final bid to enhance competitiveness. Although risk apportionment affects a contractor’s pricing strategy, other complex microeconomic factors also affect price. Instead of including pricing contingencies, risk was priced primarily through contractual rather than price mechanisms to reflect commercial imperatives. These findings explain why some assumptions underpinning analytical models may not be sustainable in practice and why what actually happens in practice is important for those who seek to model the pricing of construction bids.     

Construction Safety in Kuwait

In gulf region countries like Kuwait, the construction process can become very challenging. In this paper, we analyze construction-related accidents in Kuwait including type of accident, type of injury, body part injured, and accident outcome for the years 1996–2007. We present examples of recent cases and evaluate these cases presenting current Kuwaiti rules and legislation and providing suggestions for ensuring a safer construction environment. As this research shows, the construction industry is the most hazardous industry in Kuwait. On average, falls are the major type of accident (33.2%) followed by being crushed or struck by a falling object (25.2%). Use or misuse of tools caused the third largest number of accidents in Kuwait (18.1%). The most frequent type of injury is fractures (52.6%) and the most common injured body part is the upper body (53.4%). An average of (82.7%) of victims of construction accidents in Kuwait sustain permanent disabilities. It is clear that the Kuwaiti construction industry has a safety problem and that there is a pressing need to change current practices and legislation in construction and building sites.