Experimental and analytical study on performance of seismic sway braces for suspended piping systems

Abstract

The severe damages to nonstructural components (NSCs) are frequently reported following earthquakes. Suspended piping systems are among the most common NSCs, since they are widely installed in modern buildings. As demonstrated by the failures reported after earthquakes, piping systems are often subjected to piping connection damage, or damage resulted from inadequate braces. Therefore, there is an increasing need to understand the seismic performance of widely used seismic sway braces for suspended piping systems. In the current study, a series of component-level tests were conducted to estimate the performance of seismic sway braces. The tested specimens were constructed from C-shaped square steel channel struts, vertical threaded rod, screw fastener, top connection, bottom connection, and pre-tightening bolt. The variables considered in these tests including installation distance from the floor slab to the bottom connection, the diagonal channel inclined angle, and the number of diagonal channels. The tested specimens were subjected to cyclic loading based on loading protocol suggested by FM1950. The experimental data were then utilized to develop fragility curves for seismic sway braces. In addition to the experimental tests, analytical models for seismic sway braces were developed and calibrated using the experimental data.