近断层地震动向前方向性效应和滑冲效应对高层钢结构地震反应的影响

为考察近断层地震动向前方向性效应和滑冲效应引起的两种速度脉冲运动对高层钢框架结构地震反应的影响，选择具有向前方向性效应、滑冲效应和无速度脉冲的近断层地震动作为输入，利用SAP2000软件对一座20层平面钢框架进行非线性时程分析。计算结果表明，含滑冲效应和向前方向性效应的脉冲地震动主要激发结构基本振型反应，而无速度脉冲的地震动能够激起结构的高阶振型反应，而且，脉冲型地震动的结构破坏作用远强于无速度脉冲地震动。最后，引入了单自由度体系的能量耗散系数，从能量耗散和高阶振型影响的角度对钢结构动力反应计算结果和损伤破坏状态给出了合理解释。

Effects of forward directivity and fling step of near-fault ground motions on seismic responses of high-rise steel structure

This paper examined the influence of two types of near-fault ground motions with different velocity pulses due to forward directivity and fling-step effects on the seismic responses of high-rise steel frame structure. Near-fault ground motions with forward directivity and fling-step effects and without velocity pulse were selected as seismic inputs. The SAP2000 software was applied to model a 20-story plane frame structure, and the nonlinear time history analyses of structure were implemented. Numerical results illustrate that the ground motions with fling step and forward directivity pulses primarily excite the fundamental modal response, while the ground motions without pulse mainly excite the response of higher modes. Furthermore, the structural damage potential of impulsive near-fault ground motions is significantly greater than that of non-pulse ground motions. Finally, the energy dissipation ratio of SDOF (single degree of freedom) system was introduced, and the computational results of dynamic responses and damage state of steel structure were explained rationally from the perspective of energy dissipation and higher modal effect.