Modeling the Effect of Joint Slip in Lattice Steel Structures

Abstract

This paper proposes a simple and efficient finite-element (FE) model to accurately predict the structural response of lattice steel structures, which incorporates the effect of joint slip. The proposed model is validated by comparisons with experimental results and a conventional model. Comparisons between numerical predictions and experimental results demonstrate that joint slippage dramatically decreases the stiffness and considerably increases the displacement of lattice steel structures; however, the effect of joint slippage on the load-carrying capacity and failure mode is not significant when the structure is subjected to transverse loading. The conventional model, which does not account for the effect of joint slippage, significantly overestimates the stiffness and substantially underestimates the displacement of lattice structures, whereas the proposed model predicts the response of lattice steel structures with reasonable accuracy. The force-deflection relationship in the COMBIN39 element is one of the most critical factors that affect the accuracy of the predictions of the proposed model. The proposed model is useful in estimating the performance of lattice steel structures while considering joint slip without full- or reduced-scale testing and also has the potential to be used in the design stage for accurately assessing the reliability and safety of such lattice structures.