Cyclic performance and analytical study of novel energy-consuming brace using rubber strips for suspended pipe system restraints

Abstract

Suspended pipe systems were prone to be damaged during earthquakes, which also led to severe consequences such as personnel injury and economic loss. Seismic sway supports were generally installed for pipe systems to resist the seismic force. However, pipe systems still exhibited unexpected failure owing to the limited seismic performance of sway pipe supports. This paper proposed a novel energy-consuming brace that could be used in seismic sway supports, in which the rubber strips were compacted in the brace to dissipate the seismic energy. A total of three different rubbers including high damping, polyurethane and butadiene rubbers were selected and tested to obtain their mechanical properties. Cyclic tests were then performed on the novel rubber brace, and the test parameters were loading speed, interval time, rubber length and compacting deformation. Subsequently, detailed work mechanism of the braces with different types of rubbers were analyzed, in which the rubber strips both appeared shear and slip deformation in the brace. Test results showed that the rubber type, compacting deformation and rubber length had conspicuous influence on the hysteretic performance of the rubber brace, and the bearing capacity increased significantly with the increase of rubber length and compacting deformation. Analytical method was proposed to predict the envelope curves of novel braces considering the interactive work mechanism between the rubber strips and sawtooth in different stages. Also, the Bouc-Wen model was employed to fit the hysteretic curves of rubber braces. The research results validated that the proposed energy-consuming brace had favorable hysteretic performance and excellent energy dissipation capacity, which might provide a reasonable method to enhance the seismic behavior of pipe system.