MS, University of Cincinnati, 2003, Engineering : Civil Engineering

Workers at elevated positions must be protected from falling or from hazardous consequences of falls. A horizontal lifeline system (HLL) is a commonly used fall arrest system (FAS) that provides protection such that when a fall does occur, the fall would be stopped promptly in a manner that prevents injury. Although the HLL systems have been in use for several decades, the design of these systems is generally completed using simple methods. One popular design method is based on a simplified energy balance analysis, which is to predict the maximum force and the maximum displacement for a fall of one person. This method may be applied to the special case of multiple persons falling only with the restrictive assumption that all people in the system must fall precisely simultaneously. It is generally regarded that this assumption is implausible and furthermore, the validity of consequent solution has not been verified because of limitation of the analysis method. The present research shows the simultaneous-fall assumption may result in an unconservative solution. In this paper, a numerical time-history method is introduced. Based on this method, two computer programs are developed: one for the single-person fall and the second for the two-person fall. Satisfactory agreement has been found in comparison with previous research results. Using these programs, an extensive parametric analysis has been conducted on the configuration of the HLL system. Suggestions for design optimization are provided.

Committee: Dr. Frank Weisgerber (Advisor) Subjects: Engineering, Civil

MS, University of Cincinnati, 2002, Engineering : Civil Engineering

To protect workers at elevated positions from falling, many fall protection systems are used. Generally, fall protection systems are divided into two categories: fall restraint systems and fall arresting systems. In this thesis, emphasis is given to the H-shaped horizontal lifeline (HHLL) fall protection system, which belongs in the fall arresting category. Various fall protection systems are first introduced and the advantages and disadvantages are compared. Explanations about the competitiveness of the HHLL system and the importance of giving attention to the HHLL system are stated followed by the basic cable theories, which constitutes the background of the thesis. The force and displacement analysis of the HHLL system proceeds in several stages. In the first stage, single-span HHLL systems with different configurations are analyzed with a simplified consideration of the cable self-weight. In the second stage, a refined method is followed because the self-weight is found to have much effect on the analysis. In the refined method, the self-weight is accurately calculated and the practice of setting up systems on the site is considered for detailed analysis. In the third stage, simple multi-span systems and four selected configurations of overlapped-cable multi-span systems are analyzed and compared. Finally, a system configuration is recommended based on the evaluation of the overall system performance.

Committee: Dr. Frank E. Weisgerber (Advisor) Subjects: Engineering, Civil