Inelastic Seismic Test of the Small Bore Piping and Support System: Part 2 — Static Failure Test for Piping Support Equipment

In this paper, we focused on small-bore piping with a diameter less than 4 inches including support equipments on base concrete, with the purpose of verifying a sufficient seismic design margin. The support element tests were designed to obtain the relationship between force and displacement at piping, when the seismic force loaded on piping support equipments consisting of a U-bolt, support element, base plate, anchorage on a base concrete by confirming the behavior of the equipments as it reaches its failure. The support element tests are the part of inelastic seismic test program [1, 2] and aimed to obtain the following basic data on small-bore piping support equipments: • Relationship between force and displacement at piping; • Failure capacity of piping equipments; • Ductility ratio of piping equipments. Our results can be separated into 4 categories based on the relationship between piping force and displacement and failure mode. Tested failure capacity was higher than the designed allowable force for all failure by a factor of 1.5 to 23, indicating a margin of failure capacity. Cantilever support type have a low ductility ratio when there is the snap of expansion anchor or U-bolt and a high ductility ratio when there is significant plastic deformation of the support. Like their cantilever type counterparts, frame support type have a low ductility when there is the snap of expansion anchor and a high ductility ratio when there is significant plastic deformation of the support and U-bolt, even with brittle failure.