College of civil engineering, Chongqing University
Natural Science Foundation of Chongqing, China(cstc2018jcyjAX0001)
In order to evaluate the seismic performance of utility tunnel wall-slab joints using anchorage button-head reinforcement, pseudo-static tests were carried out on six full-scale wall-slab joint specimens. Bearing capacity, failure mode, hysteretic energy dissipation, displacement ductility and other seismic performance indexes of utility tunnel wall-slab joints were investigated. Comparing the test results of the cast-in-place wall-slab joint specimens with that of composite fabricated wall-slab joint specimens,and reasonable anchorage length of upsetting steel bar was determined. The finite element model of these wall-slab joints was established and its validity was checked. The results show that the composite fabricated wall-slab joint using anchorage button-head reinforcement has the same bearing capacity as that of the cast-in-place joint, and displacement ductility and energy dissipation capacity are good, indicating that the composite fabricated wall-slab joints can meet the seismic performance requirements. When the anchorage length of upsetting steel bar is longer than , the seismic performance of joint specimens can meet seismic design requirements. However, as the anchorage length of upsetting steel bar decreases, the bearing capacity and deformation capacity of wall-slab joints gradually decrease, and the ductility and energy dissipation capacity also decrease gradually. The crack propagation at the composite surface of prefabricated wall-slab joints is larger, and damage in the core area of the joint is severe. So necessary reinforcement measures need to be taken and the connection measures of the joint area need to be strengthened in practical engineering.