近海大气环境下锈蚀钢框架梁抗震性能试验及恢复力模型研究

为了研究近海大气环境下锈蚀钢框架梁的抗震性能，对5根钢框架梁进行了近海大气环境加速腐蚀试验和低周反复加载试验，分析了不同锈蚀程度对钢框架梁破坏模式、承载能力、变形能力及耗能能力等的影响。结果表明：随着锈蚀程度的增加，试件底端翼缘屈曲、腹板鼓曲及塑性铰形成所对应的位移逐渐减小；试件承载力及延性显著降低，强度和刚度退化明显，耗能变差。在试验研究的基础上，引入循环退化指数，建立了能够反应强度、刚度循环退化效应的锈蚀钢框架梁恢复力模型；并与试验滞回曲线进行对比，两者吻合较好，验证了该恢复力模型的适用性。研究成果为近海大气环境下在役钢结构的抗震性能评估奠定了试验与理论基础。

EXPERIMENTAL AND RESTORING FORCE MODEL RESEARCH ON THE SEISMIC BEHAVIOR OF CORRODED STEEL FRAME BEAMS IN OFFSHORE ATMOSPHERIC ENVIRONMENT

To study the seismic behavior of corroded steel frame beams in offshore atmosphere environment, accelerated corrosion test of offshore atmosphere environment and low cyclic loading test on 5 steel frame beams were implemented. The effects of corrosion degrees on the failure mode, strength, deformation capacity and energy-dissipating capacity of the samples were analyzed. The test results show that as the corrosion degree increases, the lateral displacements corresponding to flange buckling, web buckling and plastic hinge formation at the beam-bottom reduced gradually; the load bearing capacity and ductility decrease significantly; the strength and stiffness degenerate obviously and the energy dissipation capacity degrades. On this basis, a restoring force model of corroded steel frame beams was established by introducing the cycle degradation indices, which can reflect the mechanical properties such as strength attenuation and stiffness degradation. The calculation results of hysteretic curves are consistent with the test results, which verifies the applicability of the proposed model. This study may provide experimental and theoretic basis for anti-seismic evaluation of existing steel structures in offshore atmospheric environment.