抄録
In order to investigate the failure modes of piping systems under excessive seismic loads, a series of shaking table tests on elbow pipe specimens has been conducted. In the experiment, steel pipe elbows and lead pipe elbows were used as the specimens. Obtained failure modes are classified into following three modes; 1) fatigue failure, 2) ratchet-collapse, and 3) large deformation. From the experiments and a lot of preceding studies, the most possible failure mode would be the fatigue failure. Under some extreme conditions, such as large primary stress was caused by the deadweight, ratchet-collapse or large deformation would occur. It seems that the direction of the gravity affects a lot on the occurrence of the ratchet-collapse. The primary stress level would also be an important factor. But other factors to dominate failure behavior are still not clear, so further experimental or analytical studies are necessary.
