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塑性铰模型已被日本JSCE、美国Caltrans、新西兰NZS和中国(征求意见稿)等国家的桥梁抗震规范采纳,用于评价钢筋混凝土桥墩的位移(延性)能力。随着基于性能/位移抗震设计理论的发展,相继提出了残余位移、极限曲率及曲率延性系数、纵筋和混凝土的最大应变、纵筋低周疲劳损伤等桥墩地震损伤量化指标。选用5种常用塑性铰模型,通过数值分析和试验数据对比研究了利用塑性铰模型对上述损伤指标进行估计的准确程度及主要影响因素。结果表明:塑性铰模型计算的滞回曲线及残余位移和试验结果十分接近,但会高估桥墩最终破坏时纵筋的最大拉应变,低估核芯混凝土的最大压应变;对剪跨比λ≥8的(高)桥墩计算的极限曲率小于试验值,可能会导致偏于不安全的设计结果;在最大加载控制位移相同条件下,加载方式对上述损伤指标的计算结果影响较小。
The plastic hinge model has been adopted by the seismic resistance codes of Japan for JSCE, Caltrans of the United States, NZS of New Zealand and China (draft for soliciting opinions) to evaluate the displacement (ductility) of reinforced concrete piers. With the development of performance-based / displacement-based seismic design theory, quantitative indicators of earthquake damage such as residual displacement, ultimate curvature and curvature ductility factor, maximum strain of longitudinal reinforcement and concrete, and low-longitudinal fatigue failure of longitudinal reinforcement are proposed. Five kinds of commonly used plastic hinge models are selected. The accuracy and main influencing factors of the above damage indexes are compared and analyzed by numerical analysis and experimental data. The results show that the calculated hysteresis curves and residual displacements of the plastic hinge model are in good agreement with the experimental results. However, the maximum tensile strain of the longitudinal reinforcement is overestimated and the maximum compressive strain of the core concrete is underestimated. The calculated maximum curvature of 8 (high) piers is less than the test value, which may lead to the unsafe design result. Under the same conditions of maximum load control displacement, the loading method has little effect on the above damage index calculation.