Cognitive Approach to Construction Safety: Task Demand-Capability Model

In the evolution of safety research, the literature identifies three paradigms: normative, error-based, and cognitive engineering. Traditionally, strategies to improve construction safety have been based on the normative paradigm—compliance with prescribed safety rules. However, the normative approach ignores how the characteristics of the production system and team processes influence the work behaviors and the possibility of errors and accidents. These factors are the focus of the cognitive engineering perspective. This study develops a cognitive model of construction safety, which conceptualizes safety as an emergent property of the production system. The model proposes that during a task, the task demands and the applied capabilities determine the potential for errors and accidents. It also proposes that the production practices and the teamwork processes of the crew shape the work situations that the workers face—that is, the task demands and the applied capability. Empirical evidence from recent case studies is discussed. The cognitive perspective shifts the focus of accident prevention from conformance with rules to the issues of task demands and applied capabilities, and the factors affecting them—such as work design, workload, resource allocation, and team processes.     

Spatial and Temporal Exposure to Safety Hazards in Construction

Given the dynamic nature of construction sites, analysis of construction activities and their related hazards is inadequate for reliable risk assessment if it does not explicitly account for the likelihood of exposure of potential victims to hazardous situations. In traditional risk level calculations for manufacturing industries, the number of victims is factored with the likelihood of an accident and the potential severity, but the victims are simply assumed to be those typically present at the accident location. In construction, exposure cannot be accounted for at a generic metaproject level: it must be assessed at the level of the activities and the physical context in which they are performed. Conceptually, accidents are “loss-of-control events” to which victims are exposed; without exposure, no accident is assumed to occur. A set of algorithms has been developed to demonstrate estimation of the likelihood of exposure of construction workers to loss-of-control events. The algorithms have been implemented in a prototype software application designed to predict fluctuating risk levels in construction projects. The software implements the “construction hazard assessment with spatial and temporal exposure” model for managing safety in construction, which empowers planners at all levels to adjust construction plans to mitigate high levels of risk or to undertake appropriate proactive measures to ensure safety when high risk levels are unavoidable.     

金矿地下开采生产过程安全影响因素分析

科学、全面、清晰地分析金矿生产过程的危险性因素是金矿企业安全生产管理和技术提升的前提和关键。该文从目前国内金矿企业生产中危险性最高、事故发生最频繁的地下开采入手,分析了地下开采生产的特点、事故类型,并以事故致因理论为指导,参考相关的安全法律、法规,全面系统地分析总结了人员、管理、环境、设备、生产技术与安全技术等方面的安全影响因素,构建了金矿地下开采安全生产体系及其关联关系。     

Identification and Analysis of Factors Affecting Safety on Construction Sites with Tower Cranes

Tower cranes are the centerpiece of production on today’s typical building construction sites. Tower cranes hoist and transport a variety of loads near and above people, working under crowded conditions, occasionally with overlapping work zones, and often under time, budget, and labor constraints. This work regime further increases the safety risk on sites that are inherently hazardous workplaces. This paper presents the results of a study that identified the major factors affecting safety in tower-crane environments and evaluated the degree to which each factor influences ongoing safety on site. Use of statistical data on accidents was ruled out as a source of information due to the countless number of incidents that go unreported, the common inability of statistics to provide root causes, and the questionability of statistics as a predictor of accidents. The research methodology was therefore based on comprehensive questioning of an expert team that included the safety managers and equipment managers of leading construction companies. With the limited resources available for safety improvement and accident prevention, greater attention must be paid by all parties involved to those factors evaluated as highly affecting site safety due to tower-crane work.     

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.     

Development of Causal Model of Construction Accident Causation

Accidents occur in all types of construction activities. The accident causation process is complex. Accident prevention requires a comprehensive understanding of this complex process. This paper proposes a conceptual, but practical, model of accident causation for the construction industry, highlighting the underlying and complex interaction of factors in the causation process. The model describes the constraints and responses experienced by the parties involved in project conception, design, and construction, which may affect accident causation. This paper details theoretical findings of research currently being conducted at UMIST. Both proximal and distal factors are considered (for example, operative factors, site environment and systems of work, and project management and organizational issues). A study of 500 accident records provided by the U.K. Health and Safety Executive shows that accidents in construction projects involve inappropriate construction planning (28.8%), inappropriate construction control (16.6%), inappropriate construction operation (88.0%), inappropriate site condition (6.0%), and inappropriate operative action (29.9%). Data currently available are, in some respects, inadequate and will need to be supplemented, in the future, by extended accident investigations.     

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.     

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.     

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.     

解析采矿安全管理与事故防范措施

在我国社会经济体制健全发展背景下,各行各业都取得了不同程度的发展和进步。而对于金属资源的开发而言,采矿工作本身就具备较为显著的危险性,但是一些矿产企业为了降低和控制工作成本,在不断提升产量的同时,也在工作中出现了较多的安全隐患,如果不能及时发现这些安全隐患和工作问题,必然会引发不同程度的矿产资源安全事故。     

Injury risk factors in children with attention deficit hyperactivity disorder.

Processes related to injury in children with Attention Deficit Hyperactivity Disorder (ADHD) were examined. Two groups of 7–11-year-old boys (14 ADHD and 16 controls) watched a videotape simulating play activities in order for them to identify risky behaviors and then answered questions about risky scenes. Groups did not differ in ability to identify hazards, but children with ADHD anticipated less severe consequences following risky behavior and reported fewer active methods of preventing injury than did controls. Cognitive factors, including lower expectations of personal risk in hazardous situations and less ability to generate prevention strategies and safety rules, may contribute to increased injury liability in boys with ADHD. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

浅孔采场冒顶片帮事故原因分析及预防

针对三鑫公司浅孔回采采场冒顶片帮事故约占采矿作业事故的40％以上的现状,首先分析了浅孔采场稳定性的影响因素,进而又详细分析了浅孔采场冒顶片帮事故产生的原因,为了预防及其控制事故的发生,确保安全生产,提出了相应的预防措施,对实现三鑫公司的安全生产,避免采矿作业伤亡事故的发生具有重要现实意义。     

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.     

A strategic response to the occupational health establishment

The experiences of occupational health and safety "activists" in Canada reveal the limits of achieving reform in working conditions by technical efforts in combination with rank-and-file activation. The author argues that the way union "activists" approach occupational health and safety limits workers in dealing with their actual experiences and understanding about workplace hazards and risks, then discusses the condition for the awakening of their critical consciousness as a basis of acting on hazardous working conditions. The first movement in the way the worker apprehends the work environment is a movement of negation and is the prior condition to a critical and disclosive discourse about workplace hazards. It is the positive side of "No!" and the taking seriously of workers' rights. It is this negation of the negative that holds out the greatest hope for solidarity and a liberatory community in workplaces, since legislated workers' rights as the basis of protection have become a facade. Workers can respond with the power of saying "No!" in solidarity with suffering workers, and then work through appropriate principles, ends, or strategies avoiding entrapment by a "telos" in the first instance. By laying out these "ends" or a strategic paradigm, one introduces a "conversation stopper" for workers and atrophies their activation.     

Safety as an Emergent Property: Investigation into the Work Practices of High-Reliability Framing Crews

With regards to safety, the challenge for researchers and practitioners is to develop work systems that can achieve at the same time high levels of productivity and safety. Towards this objective, this research investigates the work practices of high-reliability crews—that is, crews who perform high-risk work with exceptionally high productivity and safety. The objective of the research is to increase understanding of the work practices that reduce the likelihood of accidents while at the same time increase productivity. This paper presents the findings of an initial exploratory study that compares the work practices of two residential framing crews: one crew with consistently exceptional levels of safety and productivity, and one average-performing crew from the same company. The two crews did not show any difference in safety practices—both crews had high compliance with the company’s safety requirements. However, the production practices of the high-reliability crew were shaped by a clear “guiding principle,” which is a strong focus on avoiding errors and rework, and by specific strategies that support this principle. Such strategies include actions to prevent disruptions, controlling the production pressures, matching skills with task demands, and carefully preparing and coordinating the high demand tasks. These practices prevent production errors while also reducing the likelihood of accidents. The findings provide directions for further research.     

Comparative Performance Evaluation of Tele-Operated Pipe Laying

Excavation, in particular, trenching, presents a hazardous working environment for workers. Many deadly accidents still occur even though the Occupational Safety and Health Administration has increased its training for safe trenching. The work presented in this paper originated with the belief that the best approach to remedy this problem is technology. Its premise is the need to remove the workers from this deadly trap and replace them with a mechanical device capable of doing the work necessary to lay pipes accurately. Presented is the result of a comparative field evaluation designed to prove that such a technology is not only technically feasible, but also cost-effective. For this purpose, a tele-operated pipe manipulator was built, capable of being easily attached to an excavator bucket and controllable from the safety of an operator cabin. The new technology was subsequently evaluated during field tests using both qualitative and quantitative performance criteria. Data from the study clearly demonstrate that this technological intervention not only works as intended, but also promises to reduce the cost of installing pipes, especially with increasing trench depths.     

Saving Lives and Money with Robotic Trenching and Pipe Installation

Excavation, and in particular trenching and pipe laying, represent a hazardous working environment for humans. Many hazards exist, including trench walls that can collapse, heavy objects that can be accidentally dropped into the opening, and buried utilities (e.g., power lines) that are damaged during the operation. Workplace safety has become a major concern in the construction industry over the past few decades. The main accident prevention efforts used for trench excavation and pipe installation today are the use of the trench box, appropriate sloping of trench walls, and the training of site personnel. The Construction Automation and Robotics Laboratory at North Carolina State University has developed an alternative that is using advanced technology, the prototype robotic excavation and pipe installation system. The major mechanical components are a backhoe excavator and a pipe manipulator attachment. Joystick control of hydraulic actuators, data acquisition∕processing, CAD interface, and automatic as-built generation represent the main software∕hardware components. The integration of an excavator with a pipe manipulator attachment, video cameras, beam-laser, spatial-positioning system, and CAD represents an innovative approach to reduce the number of terrible accidents and fatalities in this industry. The success of transferring this technology into the industry, however, will depend on how much a contractor can benefit economically. One key item is the cost associated with the efforts that are required by the Occupational Safety and Health Administration (OSHA) to protect workers in an open trench. Because workers do not need to enter the trench, OSHA regulations do not have to be followed; thus a major cost factor is eliminated. This paper will not only discuss the developed hardware and software, it will also present the potential economic benefits of robotic excavation and pipe installation.     

用信息扩散理论分析高海拔、寒、旱地区矿山事故风险

利用青海省安全监督管理局数据库近六年以来矿山事故数据,采用信息扩散理论,从矿山事故概率和矿山事故人员死亡概率两个方面对高海拔、寒、旱地区矿山事故进行风险分析,建立了适合本地区特殊要求的矿山事故分析模型.分析模型、参数和预测结果均与实际情况吻合,说明应用信息扩散对高海拔、寒、旱地区矿山事故进行风险分析,能够预测出该地区矿山企业年均发生事故的概率及矿山事故人员死亡概率.      

基于光纤传输的尾矿库安全监测预警系统研究

尾矿库是矿山企业生产的最大安全隐患,一旦失事会给社会、生态环境带来巨大危害.建立尾矿库安全监测预警系统,可以实时掌握尾矿库运行状况,及时发现溃坝险情,采取防溃措施或安全转移,最大程度减少损失,保障人民生命财产安全.光纤传输具有高速率远距离、大容量低损耗、多业务、不受电磁波干扰、扩容方便等优点,介绍了光纤传输基本原理和在...