窗户孔洞对砖石古塔地震反应的影响

Effect of Window Hole on Seismic Response of Ancient Masonry Pagoda

以四川省都江堰奎光塔为工程背景,采用ANSYS软件建立实体有限元模型,应用时程反应分析法分析窗户孔洞对砖石古塔塔身控制截面应力分布规律,揭示该塔在2008年汶川地震中的震害机理。结果表明:塔身10层顶(塔身双层与单层的转换处)与1层顶为主塔抗震薄弱部位。砖石古塔窗孔附近区域应力集中现象较为突出,墙体外缘的最大、最小主应力都明显高于墙体内缘,靠近窗户附近区域的应力约为远离窗户处应力的2~3倍。在垂直于地震激励方向的主塔对称轴截面上,在窗顶出现较明显的剪应力集中,因此强震时窗顶为抗震薄弱部位。

Using the Kuiguang Tower in Dujiangyan city,Sichuan province as our engineering background,we used ANSYS software to establish a solid finite element model and analyzed the effect of a window hole on the stress distribution law of the control section of this ancient masonry pagoda.To do so,we conducted a time-history analysis and also identified the damage mechanism of the tower during the 2008 Wenchuan earthquake.The results show that the first and tenth floors of the tower（at the transformation from double to single layers）are seismically weak.Stress concentration occurs near the window of the ancient masonry pagoda,and the maximum and minimum principal stresses of the outer wall are significantly higher than those at the inner edge of the wall,with the stress near the window about 2-3times that far away from the window.At the symmetry axis section of the main tower perpendicular to the direction of earthquake excitation,we found the shear stress to concentrate at the top of the window,thus revealing the top of the window as a weak spot with respect to strong earthquakes.