Modeling methods of self-centering energy dissipation braces using OpenSees

Abstract

Self-centering energy dissipation (SCED) braces as a high-performance structural member has been extensively investigated in the last decade. The unique hysteretic behavior of the SCED brace generally dominates the seismic performance of building structures. This paper presents three available simulation methods for predicting the hysteretic behavior of a typical SCED brace in the widely-used open-source computational platform OpenSees. The simulation methods are implemented using the built-in material and element libraries in OpenSees, and aim to investigate the advantages/disadvantages between different modeling methods. Furthermore, two general-purpose self-centering (SC) uniaxial hysteretic models are developed and implemented for modeling different types of SCED braces. Representative validation studies are then presented through using the developed material models to predict the experimental results of the SCED braces under cyclic loading. The SC hysteretic models can capture primary characteristics of hysteretic responses with reasonable accuracy. Additionally, an improved truss element is also proposed for straightforward application of the developed SC models. The users are able to define the experimentally-observed hysteretic features of the SCED braces in line with the envelopes established in the developed material models. A shaking table test of the SCED braced frame in the literature is further simulated to verify the feasibility of the developed material models and modified truss element under seismic loadings. The research outcomes validate a more convenient and accurate method for predicting the behavior of SCED braces and provide some useful insights on the modeling methods in OpenSees.