外加强环式H型钢梁-方钢管角柱节点抗震性能

Seismic performance of H-shaped steel beam-to-square steel corner column connection with external strengthened ring

通过对5个试件进行拟静力加载试验,研究了加载方式对角柱和边柱节点抗震性能的影响.试验通过对加载方式（单向加载、双向轴对称加载和双向中心对称加载）和钢管柱宽厚比（D/t=22和33）主要参数的变化分析,着重研究了试件的滞回性能、刚度退化和耗能性能等特性.试验结果表明：加载方式对试件刚度及承载力影响十分明显.在双向中心对称荷载作用下,试件的承载力比在单向荷载作用下试件的承载力降低约20%;而在双向轴对称荷载作用下,试件的承载力与在单向荷载作用下试件的承载力基本相同.方钢管柱宽厚比是影响试件承载力的主要因素之一,随着宽厚比的增加,试件承载力逐步减小.所有试件的滞回曲线均呈饱满的纺锤体状,等效黏滞阻尼系数在0.2左右,具有稳定的耗能能力.

Beam-to-column connection plays a key role in structure designs,especially for steel structures,as the seismic performance the connection directly affects the safety,reliability,utilization,and economic indicators of steel structures.During the Northbridge earthquake in the USA and Hyogoken Nanbu（Kobe） earthquake in Japan,several steel structures collapsed because of unexpected brittle fractures around the beam-to-column connections.The economic loss encountered in the Kobe earthquake is estimated to be about 10 trillion JPY（approximately 580 billion RMB）.Moreover,it caused approximately 6500 civilian fatalities and destroyed tens of thousands of houses in Kobe and the surrounding cities.The corner beam-to-column connection suffered from complicated seismic loadings during the earthquakes.Corner beam-to-column connections are the weak points in an aseismic design,and under biaxial lateral loadings,they induce large torsional deformations.In this study,five specimens were tested under pseudo-static loadings to investigate the influence of loading paths on the seismic behavior of corner or side beam-to-column connections.The main experimental parameters were the loading paths（uniaxial loading,biaxial symmetrical loading,and biaxial center symmetrical loading） and widthto-thickness ratio of the steel column（D/t = 22 and 33）.The main seismic characteristics of specimens were studied,such as the hysteretic behavior,stiffness degradation,and energy dissipation.The results indicate that the loading paths affect the stiffness and bearing capacities of the specimens.The bearing capacities of the specimens under the biaxial center symmetrical loading are 20% lower than those under the uniaxial loading,while the bearing capacities of the specimens under the biaxial symmetrical loading are equal to thoseunder the uniaxial loading.The width-to-thickness ratio of the square steel column is one of the key factors that affect the bearing capacities of the specimens.The bearing capacities gradually decrease with an increase in the width-to-thickness ratio.All the specimens exhibit a good energy dissipation capacity,and the hysteretic curves are stable and numerous.The equivalent viscous damping coefficients of all the specimens are around 0.2.