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原文传递 A Procedure for Assessing Low-Cycle Fatigue Life of Buckling-Restrained Braces

题名：	A Procedure for Assessing Low-Cycle Fatigue Life of Buckling-Restrained Braces
正文语种：	eng
作者：	Li, Chao-Hsien;Vidmar, Zac;Saxey, Brandt;Reynolds, Mathew;Uang, Chia-Ming
作者单位：	Univ Calif San Diego Dept Struct Engn La Jolla CA 92093 USA;CoreBrace LLC 5789 Wells Pk Rd W Jordan UT 84081 USA;CoreBrace LLC 5789 Wells Pk Rd W Jordan UT 84081 USA;4350 Still Creek Dr Suite 210 Burnaby BC V5C 6C6 Canada;Univ Calif San Diego Dept Struct Engn La Jolla CA 92093 USA
关键词：	Buckling-restrained braces (BRBs);Low-cycle fatigue;Fatigue life assessment
摘要：	Buckling-restrained brace frames (BRBFs) have been a popular seismic force-resisting system in the US since it was first introduced to the AISC Seismic Provisions and ASCE 7 in 2005. The steel core of a buckling-restrained brace (BRB) yields in tension and buckles plastically in a high-mode buckling pattern in compression under cyclic loading. Prequalification testing of BRBs in conformance with the AISC 341 requirements relies on a highly idealized loading protocol that is not representative of the expected response during an earthquake. Although testing has demonstrated that BRBs have excellent energy dissipation capacity, a low-cycle fatigue model will permit designers to evaluate the remaining life of BRBs after a seismic event. To develop and validate such model, 18 full-scale BRBs in groups of three different yielding strengths (1,110; 2,220; and 3,330 kN) were cyclically tested to fracture with the following loading conditions: (1) symmetric cycles with constant strain amplitudes (+/- 0.25% to +/- 3%), (2) asymmetric cycles with constant strain amplitudes and non-zero-mean strains, (3) symmetric cycles with variable strain amplitudes, and (4) simulated earthquake responses. Two low-cycle fatigue models for BRBs (a standard model and an alternative model for ease of practical use) were developed based on 11 symmetric, constantamplitude tests. An assessment procedure combining the proposed fatigue models, rainflow cycle counting method, and Miner's damage index was proposed to predict the fatigue life of BRBs subjected to random cyclic loading histories, the accuracy of which was verified by the variable-amplitude test results. (C) 2021 American Society of Civil Engineers.
出版年：	2022
期刊名称：	Journal of structural engineering
卷：	148
期：	2
页码：	04021259.1-04021259.15