Static Resistance of Open Web Steel Joist Roof Trusses for Blast Response Analysis

摘要

Open web steel joists (OWSJs) are prefabricated lightweight roof structure components that are designed for conventional loads in accordance with current standards and specifications. The resistance function currently used to design joists against blast loading is linearly elastic and perfectly plastic after the elastic deflection limit, which does not account for the different failure mechanisms of the joist components and system. For blast analysis and design of such roof trusses, further investigation of the behavior of these joists is needed. This paper presents numerical modeling and experimental evaluation of three different steel joist systems to failure to develop an accurate representation of the static resistance and energy absorption capabilities of OWSJ roof trusses to failure. Experimental results were used to verify robust explicit numerical models for predicting the static resistance function of OWSJ roof trusses. A deformable weld behavior was used to simulate all spot welds connecting web members to the joist top and bottom chords. Additionally, a criterion that predicts the failure of the end connection bearing seat of the joist system was included in the numerical simulation. The results of the numerical modeling and the experimental evaluation demonstrate the inadequacy of the current resistance models used for blast analysis purposes based on energy comparisons using various damage levels. (C) 2017 American Society of Civil Engineers.