Risk factor quantification of design elements for multistory commercial office buildings

Graduation date: 2012Designing for construction safety is part of standard practice in countries such as the UK, Australia, and South Africa. Designing the permanent facility in a manner to eliminate or reduce the risks of injury, illness, or fatality of construction workers is defined as designing for construction safety (DfCS). Although evident through research that design is one of the contributing factors to construction hazards, the US construction industry has been resistant in implementing DfCS. Lack of designers' knowledge about the construction processes and limited availability of DfCS tools are examples of inhibitors to the development and implementation of DfCS. \ud \ud This thesis describes a research effort to develop a DfCS tool that provides knowledge of the construction processes to the designer and helps the designer evaluate design elements in terms of risk factors. The tool, which focuses on a multistory commercial office building, was developed using results obtained from a comprehensive field survey and analysis program on safety risks associated with constructing different design features.\ud \ud The field survey program included the accumulation of 89 design elements and 473 construction activities from construction literature. Using survey methodology, the average exposure and average frequency of four severity categories were obtained for each construction activity. The inputs were provided by superintendents and/or safety managers of general contracting and trade contracting firms. Together the respondents provided a total of more than 33,800 ratings. The analytical program included conversion of the ratings obtained from the field survey program into unit risk and cumulative risk factors using appropriate scales and computations. The results of this research include the quantification of the unit risk and cumulative risk factors for the 89 design elements and the 473 construction activities. These were put into a MS Excel® spreadsheet which can be used for designing for construction safety.\ud \ud The data was also used to analyze comparisons between risk perceptions of the respondent groups. Group comparisons were made between general contractor superintendents vs trade contractors, general contractor safety managers vs trade contractors, and general contractors vs trade contractors. Using cast-in-place concrete column as an example, the activity risk factors, the four severity category risk factors, and the total risk factors were individually compared. The results indicate that there is no evidence of a difference in risk perception between general contractor superintendents and general contractor safety managers in terms of risk ratings for the activity risk, severity categories, and total risk comparisons. The construction and removal of formwork and pouring of concrete show moderate to suggestive evidence of a difference in the sample mean risk perceptions for the three group comparisons. For the four severity levels and total risk comparisons, there is moderate to suggestive evidence of a difference for medium severity, high severity, and total risk for the three group comparisons. There is no evidence of a difference in the way the groups perceive near miss risks.\ud \ud Additionally, comparison between design elements was analyzed. For steel stud versus concrete masonry unit block partition walls, there is moderate evidence that on an average, the construction of CMU block wall has a larger cumulative risk of medium severity and high severity injuries. There is suggestive evidence that the average near misses are more for CMU block partition walls than for steel stud partition walls. Finally, there is moderate evidence that on an average, the total cumulative risk associated with CMU block wall construction is more than that during steel stud wall construction