Seismic response and failure mechanism of underground frame structures based on dynamic centrifuge tests

During the 1995 Kobe earthquake in Japan, the Daikai subway station suffered total collapse, which made the research on the seismic failure mechanism of underground frame structures become a hot topic. The author has carried out a lot of research on earthquake failure mechanism of underground frame structures based on numerical method. To validate and further study the seismic failure response and mechanism of underground frame structures, a series of comparative dynamic centrifuge tests were carried out. The research conclusions are as follows. The vertical earthquake action significantly increased the axial pressure on the columns of an underground frame structure, reducing their horizontal deformation capacity. The columns subjected to high axial compression were prone to brittle damage under a relatively strong horizontal earthquake, which led to the overall collapse of an underground frame structure. The areas near the intersection of the ceiling slab and the sidewalls were the weak part of the underground frame structure and were vulnerable to tensile cracks under earthquake. The columns' top and bottom were the fragile parts and were prone to concrete cracking or even shear failure under an earthquake. If the columns could remain intact and effectively provided vertical support under a strong earthquake, it was beneficial to reduce the risk of the overall collapse of an underground frame structure.

Automated summary

The seismic failure mechanism of underground frame structures includes increased axial pressure on columns, brittle damage, and vulnerable areas prone to tensile cracks. The top and bottom of columns are fragile parts, but if intact, they can help reduce the risk of overall collapse.