SummaryNear‐field ground motions with fling‐step and forward‐directivity characteristics contain large‐amplitude pulses in velocity history, causing severe damage to stilted buildings in mountainous areas. In this study, three groups of 20 near‐field ground motions with fling‐step and forward‐directivity characteristics and 10 far‐field ground motions were selected as seismic inputs. Nonlinear response history analysis (NLRHA) was performed on plane finite element models of two seven‐story stilted frame structures, one with steel braces in the stilted story and the other without steel braces in the slope direction. Structural seismic response obtained from NLRHA was discussed in terms of inter‐story drift ratio (IDR) and peak floor acceleration (PFA). In addition, damage to two structures was assessed using the modified Park–Huang damage model. The results show that stilted structures exhibit greater inter‐story ratios and damage index values under near‐field ground motions with fling‐step characteristics and forward‐directivity characteristics than far‐field ground motions, where the stilted story has the highest amplification ratio in both IDR and damage index among floors. Designers should pay sufficient attention to the influence of ground motions with fling‐step and forward‐directivity characteristics on seismic demands and damage to stilted structures. The peak inter‐story ratio and damage index of stilted structures with steel braces were significantly lower than that of stilted structures without braces, proving the validation of setting steel braces on reducing the seismic demands of stilted structures and improving structural seismic safety. Additional NLRHA performed using artificial pulses shows that the seismic response of stilted buildings is related to pulse periods of near‐field ground motions and the greatest seismic demands and damage are obtained when the pulse period is 1.5–1.6 times the fundamental period of the stilted building.

中文翻译：

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具有抛步和前向性特征的近场地震动对山区吊脚楼地震响应的影响

摘要具有抛步和前向特征的近场地面运动在速度历史中包含大振幅脉冲，对山区的吊脚楼造成严重破坏。在本研究中，选择了三组20个具有前向性和前向特征的近场地震动和10个远场地震动作为地震输入。对两个七层吊脚架结构的平面有限元模型进行了非线性响应历史分析（NLRHA），其中一个在吊脚层有钢支撑，另一个在斜坡方向没有钢支撑。从 NLRHA 获得的结构地震响应根据层间位移比 (IDR) 和峰值地板加速度 (PFA) 进行了讨论。此外，还使用修改后的 Park-Huang 损伤模型评估了两个结构的损伤。结果表明，在具有抛步特性和前向性特征的近场地震动作用下，吊脚楼表现出比远场地震动更大的层间比和损伤指数值，其中吊脚楼在两种情况下的放大率最高。 IDR和楼层间的损坏指数。设计者应充分关注具有抛步和前向特征的地震动对吊脚楼抗震需求和破坏的影响。有钢支撑的吊高结构峰值层间比和损伤指数均显着低于无支撑的吊高结构，证明了设置钢支撑对降低吊高结构抗震需求、提高结构抗震安全性的有效性。使用人工脉冲进行的附加 NLRHA 表明，吊脚楼的地震响应与近场地震动的脉冲周期有关，当脉冲周期为吊脚楼基本周期的 1.5-1.6 倍时，获得最大的地震需求和破坏。 。