Experimental study and numerical analysis on the failure mode of staggered truss framing system

Abstract

To investigate the seismic performance of staggered truss framing system under different failure modes, two trusses were designed according to the capacity design method. Then, two models with a scale of 1/2.5 were made and subjected to quasi-static tests. The hysteresis curve, stiffness, energy dissipation, and ductility coefficient of the two models were analyzed. The test results show that the specimen designed for chord failure has better seismic performance than that designed for diagonal web failure. The ultimate drift ratios of the two specimens are both less than 1.5%, indicating that the deformation ability of the staggered truss is insufficient. By analyzing the relationship between the plastic hinge rotation and the drift ratio of the truss, it is suggested that the limit value of the drift ratio of the staggered truss framing system should not exceed 1.5%. The yield-bearing capacity calculated by considering the composite effect of the chord and floor slab is closer to the test results than that calculated without considering the composite effect, indicating that the composite effect of the chord and floor slab should be considered when designing the trusses. Through the numerical analysis, it is recommended to take a minimum amplification factor of 1.3 for the internal force of web members to realize the purpose of chord failure.