Since most current seismic capacity evaluations of reinforced concrete （RC） frame structures are implemented by either static pushover analysis （PA） or dynamic time history analysis, with diverse settings of the p...Since most current seismic capacity evaluations of reinforced concrete （RC） frame structures are implemented by either static pushover analysis （PA） or dynamic time history analysis, with diverse settings of the plastic hinges （PHs） on such main structural components as columns, beams and walls, the complex behavior of shear failure at beam-column joints （BCJs） during major earthquakes is commonly neglected. This study proposes new nonlinear PA procedures that consider shear failure at BCJs and seek to assess the actual damage to RC structures. Based on the specifications of FEMA-356, a simplified joint model composed of two nonlinear cross struts placed diagonally over the location of the plastic hinge is established, allowing a sophisticated PA to be performed. To verify the validity of this method, the analytical results for the capacity curves and the failure mechanism derived from three different full-size RC frames are compared with the experimental measurements. By considering shear failure at BCJs, the proposed nonlinear analytical procedures can be used to estimate the structural behavior of RC frames, including seismic capacity and the progressive failure sequence of joints, in a precise and effective manner.展开更多
Four exterior joints with special-shaped columns which have different lengths of limbs are tested under low cyclic loading. Speeial-shaped columns adopted are L- and T-shaped in section. It can be concluded that crack...Four exterior joints with special-shaped columns which have different lengths of limbs are tested under low cyclic loading. Speeial-shaped columns adopted are L- and T-shaped in section. It can be concluded that crack pattern, failure mode and shear strength of joints are affected by the length of limb, and that shear strength and ductility increase with the length of limb; the joints with the flexural failure of the beam have better seismic behavior than those with the shear failure of the joint core.展开更多
文摘Since most current seismic capacity evaluations of reinforced concrete （RC） frame structures are implemented by either static pushover analysis （PA） or dynamic time history analysis, with diverse settings of the plastic hinges （PHs） on such main structural components as columns, beams and walls, the complex behavior of shear failure at beam-column joints （BCJs） during major earthquakes is commonly neglected. This study proposes new nonlinear PA procedures that consider shear failure at BCJs and seek to assess the actual damage to RC structures. Based on the specifications of FEMA-356, a simplified joint model composed of two nonlinear cross struts placed diagonally over the location of the plastic hinge is established, allowing a sophisticated PA to be performed. To verify the validity of this method, the analytical results for the capacity curves and the failure mechanism derived from three different full-size RC frames are compared with the experimental measurements. By considering shear failure at BCJs, the proposed nonlinear analytical procedures can be used to estimate the structural behavior of RC frames, including seismic capacity and the progressive failure sequence of joints, in a precise and effective manner.
文摘Four exterior joints with special-shaped columns which have different lengths of limbs are tested under low cyclic loading. Speeial-shaped columns adopted are L- and T-shaped in section. It can be concluded that crack pattern, failure mode and shear strength of joints are affected by the length of limb, and that shear strength and ductility increase with the length of limb; the joints with the flexural failure of the beam have better seismic behavior than those with the shear failure of the joint core.
文摘为研究穿斗式木结构的抗震性能及其加固方法,选取杉木和松木两种木材,设计并制作四榀穿斗式木结构平面外框架,采用黏弹性阻尼器加固试件,对加固和未加固的木框架分别进行低周往复荷载试验,研究结构的抗震性能及阻尼器的加固效果.研究结果表明:加固后木排架滞回曲线的滑移和捏缩现象大幅减轻,滞回环面积增大,等效黏滞阻尼比增加,耗能能力增强,杉木和松木排架耗能能力分别提高83.31%和286.34%;加固后试件的骨架曲线斜率和极限承载力均得到大幅提升,斜率大致随加载幅值增大而增大,极限承载力杉木排架最大提升218.32%,松木排架最大提升458.89%;加固后木结构框架的刚度储备增高,初始刚度杉木试件提升46.9%,松木试件提升264.1%;杉木试件在安装阻尼器后节点的残余拔榫量减少15.06 mm,松木试件减少31.96 mm.
