Finite Element Analysis on High-Temperature Response of Staggered-Steel Truss System Using Plane Cooperative Model

A numerical investigation on the structural behaviors of the steel staggered truss system (SSTS) under lateral force at elevated temperature is presented by the finite element method, using two kinds of plane cooperative model (PCM) which is a simplified but efficient means instead of the complicated and time-consuming 3-D structural analysis. And two contrary extreme situations were considered to build up the PCM and the corresponding calculated results were compared and discussed. The axial force and bending moment against temperature were analyzed and the interaction characteristics between the truss exposed to fire and its neighboring truss are studied, in order to explore the adaptability of PCM to the fire resistance analysis for SSTS under lateral force. The results indicate that: in SSTS, the interaction between the adjacent trusses may make some certain extent influence on the fire resistant property of the system. The obtained limiting temperature based on the way, merely taking the single frame truss (SFT) into account, may be relatively conservative. In PCM, the rigidly hinged bars (RHB), near the floor in fire, make little effect on the performance of the whole structure, so the model with no RHB on the floor subjected fire, based on the former model, and could be recommended to the general fire resistance analysis of the SSTS.