Di Wang

Date of Graduation


Document Type


Degree Type



Statler College of Engineering and Mineral Resources


Civil and Environmental Engineering

Committee Chair

Fei Dai

Committee Co-Chair

Roger Chen

Committee Member

Xiaopeng Ning

Committee Member

Radhey Sharma


Roofers have long suffered from low back disorders (LBDs), which is a primary non-fatal injury in construction. The harsh work environment exposes the roofers to a diversity of physical exposures which may cause severe LBD injuries. Until now, most of research on roofing safety has been mainly focused on fatal injury risks, such as falls from height, leaving much to be desired in the risk assessment of non-fatal, cumulative musculoskeletal disorders among this population. Existing ergonomics studies have identified several physical risk factors associated with LBDs in workplaces and developed predictive models for general LBD risk assessments. However, these models cannot be directly used for assessments in roof workplaces because they are designed for general tasks without considering the variance of roofer working postures and the effects of working on slanted ground surfaces (i.e., rooftops).;The objective of this thesis study is to understand the relationship between the roofing work-related risk factors and the LBD risks during the performance of roof shingle installation. The roofing work-related risk factors comprise slope angles, postures, facing directions, and working pace. An in-lab factorial experiment is conducted with the aid of Vicon and Electromyography (EMG) sensors. The trunk flexion angle and muscle activities in the low back are measured as indicators, which are then analyzed to implicate the LBD risk.;The experiment results revealed the risk factors with significant effects on the LBD development. Also, this study uncovered the relationships between trunk flexion angles, muscle activities and combinations of different risk factors. This knowledge will be useful for better understanding and education of roofing non-fatal LBD development in the industry and the research community. This knowledge may also have the potential for development of detailed safety guidelines and interventions for the LBD injury prevention among the roofer population.