The optimal arrangement of viscoelastic dampers (VEDs) used to link two adjacent shear-type structures under seismic excitation was investigated. A two-step optimal design method is proposed. First, optimal parameter ...The optimal arrangement of viscoelastic dampers (VEDs) used to link two adjacent shear-type structures under seismic excitation was investigated. A two-step optimal design method is proposed. First, optimal parameter expressions of the Kelvin model are used to calculate the optimal stiffness and damping coefficient of the VEDs. Then, using the two-step optimal design method, taking the quadratic performance index as the optimization objective, the optimal arrangement of the dampers is determined. General rules about the optimal arrangement of the VEDs were obtained. The results show that the placement of only one damper between two adjacent shear-type structures should be avoided; if more than one damper is used, they should be distributed on the top and lower floors of the structures. Optimization of the number of dampers had little effect on response reduction. The most important factor was the optimization of the placement of the dampers. Through comparative study, for buildings of equal and unequal heights, the optimal parameters of dampers from parametric studies were shown to match the theoretical results for different numbers and placements of dampers. The level of response reduction was shown to be sensitive to the damping coefficient of the dampers.展开更多
免灌浆干式连接预应力混塔竖缝界面采用环氧树脂结构胶+弯螺栓施加预紧力共同抗剪,相比传统的灌浆湿连接+连接钢筋的形式,可以极大地提高现场安装效率。为此,针对干式连接竖缝界面的抗剪性能,以足尺试件为研究对象,开展1个直剪静力试验...免灌浆干式连接预应力混塔竖缝界面采用环氧树脂结构胶+弯螺栓施加预紧力共同抗剪,相比传统的灌浆湿连接+连接钢筋的形式,可以极大地提高现场安装效率。为此,针对干式连接竖缝界面的抗剪性能,以足尺试件为研究对象,开展1个直剪静力试验和两个直剪疲劳试验。研究竖缝界面在静力剪切荷载作用下的破坏模式、黏结滑移曲线及承载力计算,进一步重点分析竖缝界面的疲劳破坏模式、剪切刚度退化及疲劳寿命计算方法。试验研究和理论分析结果表明:干式连接竖缝的静力、疲劳试验均发生脆性破坏模式,界面可分为界面脱黏破坏和混凝土保护层剥离破坏两类区域,面积占比约各50%,弯螺栓施加预紧力可以有效提高结构胶界面的黏结抗剪能力;荷载上限是影响竖缝剪切疲劳性能的关键因素,且疲劳寿命与荷载上限呈负相关;竖缝界面的抗剪能力由混凝土直接抗剪和弯螺栓预紧力产生的摩擦力共同提供,根据叠加法推导的竖缝界面受剪承载力计算公式具有较高的精度;Fib Model Code规范公式可以对竖缝的剪切疲劳寿命进行预测,预测结果具有较高的准确性和一定的安全富余,具有良好的工程应用价值。展开更多
基金Project supported by the National Natural Science Foundation of China (No. 51178203)the National Science Foundation for Distinguished Young Scholars of China (No. 50925828)
文摘The optimal arrangement of viscoelastic dampers (VEDs) used to link two adjacent shear-type structures under seismic excitation was investigated. A two-step optimal design method is proposed. First, optimal parameter expressions of the Kelvin model are used to calculate the optimal stiffness and damping coefficient of the VEDs. Then, using the two-step optimal design method, taking the quadratic performance index as the optimization objective, the optimal arrangement of the dampers is determined. General rules about the optimal arrangement of the VEDs were obtained. The results show that the placement of only one damper between two adjacent shear-type structures should be avoided; if more than one damper is used, they should be distributed on the top and lower floors of the structures. Optimization of the number of dampers had little effect on response reduction. The most important factor was the optimization of the placement of the dampers. Through comparative study, for buildings of equal and unequal heights, the optimal parameters of dampers from parametric studies were shown to match the theoretical results for different numbers and placements of dampers. The level of response reduction was shown to be sensitive to the damping coefficient of the dampers.
文摘免灌浆干式连接预应力混塔竖缝界面采用环氧树脂结构胶+弯螺栓施加预紧力共同抗剪,相比传统的灌浆湿连接+连接钢筋的形式,可以极大地提高现场安装效率。为此,针对干式连接竖缝界面的抗剪性能,以足尺试件为研究对象,开展1个直剪静力试验和两个直剪疲劳试验。研究竖缝界面在静力剪切荷载作用下的破坏模式、黏结滑移曲线及承载力计算,进一步重点分析竖缝界面的疲劳破坏模式、剪切刚度退化及疲劳寿命计算方法。试验研究和理论分析结果表明:干式连接竖缝的静力、疲劳试验均发生脆性破坏模式,界面可分为界面脱黏破坏和混凝土保护层剥离破坏两类区域,面积占比约各50%,弯螺栓施加预紧力可以有效提高结构胶界面的黏结抗剪能力;荷载上限是影响竖缝剪切疲劳性能的关键因素,且疲劳寿命与荷载上限呈负相关;竖缝界面的抗剪能力由混凝土直接抗剪和弯螺栓预紧力产生的摩擦力共同提供,根据叠加法推导的竖缝界面受剪承载力计算公式具有较高的精度;Fib Model Code规范公式可以对竖缝的剪切疲劳寿命进行预测,预测结果具有较高的准确性和一定的安全富余,具有良好的工程应用价值。
