Numerical and theoretical analysis of beam-to-column connections with ECC ring beams subjected to local compression loading

Abstract

Engineered cementitious composite (ECC) is a kind of high performance cement-based composite materials with strain hardening and multiple cracking behaviour. Replacing concrete with ECC in the beam-to-column connection with ring beam may effectively improve the load-carrying capacity and ductility, as well as prevent cracks and solve durability problems caused by the brittleness of concrete. In this paper, the failure mechanism of beam-to-column connection with ECC ring beam subjected to local compression loading was investigated with the nonlinear finite element (FE) method. The results indicated that continuous lateral pressure was provided by the ECC ring beam, which improved the local compression performance of the ring beam connection. Extensive parametric studies on the local compression behavior of connections with ECC ring beams were also conducted. According to the simulation results, the peak strength of ECC connections was 13.0%–24.2% higher than that of concrete specimens. Increasing the ECC compression strength or ring beam width can effectively increase the load-carrying capacity of the connection, but the ECC tensile strain can only affect the ductility of the connection when the ultimate tensile strain was lower than 1.5%. Based on the FE analysis, an effective restraint width of the ECC ring beam was proposed, and theoretical models were established to predict the axial compressive bearing capacity of the beam-to-column connection with ECC ring beam.