Equivalent Linear and Nonlinear Numerical Simulation of Precast Moment-Resisting Concrete Frame with Bolt-Connected Joints

Abstract

Precast RC frames with simple joints such as bolt-type connections have been constructed extensively around the world, which still possess stable application market in industrial buildings. With respect to the seismic vulnerability of this structural system, numerous numerical modelling approaches have been proposed to investigate its failure mechanism and improve its seismic performance. However, these studies concentrated on precast frames with dowel pin connections or sophisticated innovative joints, disregarding the simple bolt-connected moment-resisting RC frame. Different from conventional precast industrial buildings with hinged joints, a type of bolt-connected precast RC system with moment-resisting connections was introduced in this paper. An equivalent linear and a nonlinear numerical modelling approaches were established to simulate this precast system simultaneously. The equivalent linear models relied on the global damage indices summarized from the results of shaking table tests, whereas the nonlinear model was based on the mechanical derivation of the bolt-connected joints and the physical properties of main structure. The two modelling approaches were validated against the shaking table tests and they both had satisfactory accuracy. The equivalent linear approach is convenient for the quick simulation of bolt-connected frame but dependent on the test data. The nonlinear approach considers the real details of connections and performs better simulation effect than the linear method under severe earthquakes. Based on the nonlinear model, the stress states of rebar fibers in key structural members were analyzed and discussed as well.