Experimental and numerical study of precast bridge piers with a new UHPC socket column-footing connection: Fid-Bau Portal

Experimental and numerical study of precast bridge piers with a new UHPC socket column-footing connection

Zhang, Yingao / Chen, Liang / Zuo, Rui / Xie, Haihui / Yang, Shengwei / Zhang, Kefa / Hu, Zhangliang

Based on the approach of prefabricated and assembled bridge piers in the accelerated bridge construction (ABC), this study proposes a new precast bridge pier-footing connection using ultra-high performance concrete (UHPC) cupped socket. Compared to conventional socket connection, the UHPC cupped socket connection can eliminate the adverse effects of reserved slots on the cap beams or footings. Three UHPC cupped socket pier specimens and one cast-in-place (CIP) pier specimen are designed and cast for quasi-static tests, and the damaging pattern and hysteretic characteristics of these specimens are investigated. After verifying the accuracy of the finite element model, the numerical parametric study was conducted to investigate two design parameters. The results show that the reasonable design of the cupped socket ensures that the piers connected by the UHPC cupped socket have the same seismic performance as the CIP pier. Generally, increasing the socket height enhances the strength while also increases the residual deformation of the specimens. When the axial compression is greater, it improves the structural strength, but it is not advantageous to structural ductility. Based on the experimental and simulative results, this study analyzes the force transmission and deformation mechanism of UHPC cupped socket piers. The ultimate displacement calculation equations of UHPC cupped socket piers are compared with those of different national standards and scholars’ researches to identify applicable equations for the calculation of UHPC cupped socket piers.

This study proposes a new post-cast UHPC cupped socket connection to connect precast piers and footings, which would not pose adverse influences on the performance of footings without the need for setting concaves on footings, or cutting off footing reinforcement.

Four large-scale specimens are designed and fabricated for the quasi-static test, and the seismic performance of the prefabricated assembled piers with the new connection is evaluated. Combined with numerical simulations to investigate the effects of socket heights and axial compression on the seismic performance of piers using this new connection.

The force transmission mechanism and deformation mechanism of piers using the new connection are investigated based on test phenomenon. The ultimate displacement calculation equations given by standards from different countries and scholars are compared, and the reasonable ultimate displacement calculation equation for UHPC piers is determined.