甘堡藏寨194号杨家宅院地震模拟振动台试验研究

Experimental study on earthquake-simulated shaking table test of Tibetan village of No.194 Yang’ fort in Ganbao

以甘堡藏寨194号杨家宅院为建筑原型,根据相似比理论设计了甘堡藏寨194号杨家宅院地震模拟振动台试验缩尺模型,采用当地的石材、砂浆,并请当地工匠进行了模型砌筑,选取El Centro位移波作为地震动输入,调整位移波峰值模拟地震强度,给出了2层和3层处楼面加速度和位移沿高度的变化规律,进行了裂缝分析,结果表明：藏寨砌筑砂浆强度较低、纵横墙拉结处较弱,同时洞口为薄弱部位,且第2~3层竖向体型收进,刚度和承载力突变,进而形成＂V＂字形剪切斜裂缝;结构具有不对称的扭转效应,导致同一层的加速度和位移峰值相差10%左右;沿房屋竖向质量和刚度有突变,形成薄弱层,导致墙体在地震作用下有外闪的趋势,容易发生破坏。建议对房屋的纵横墙加强拉结,同时对薄弱部位应进行加固改造。

Taking Tibetan village of No. 194 Yang＇ fort in Ganbao as building prototype,the similarity ratio theory was used to design the scale model of the shaking table test for simulating earthquake. The model was modeled by the local artisans use local stone and mortar. The El Centro displacement wave was selected as the input of ground motion and the peak value of displacement wave was adjusted to simulate earthquake intensity. The law of acceleration and displacement along height for two floors and three floors was given. The crack analysis was carried out. The results show that the strength of masonry mortar for Tibetan village is low,and the connection of longitudinal and transverse walls are weakened,while the holes are weak. And there is vertical shape set back from second floor to third floor,to lead to abrupt change in stiffness and bearing capacity,forming of V-shaped shear diagonal cracks. The structure has an asymmetric torsional effect,resulting in about10% difference in the peak values of the acceleration and displacement of the same layer. There is a sudden change in vertical mass and stiffness along the height of the house to form a weak layer,which leads to the tendency of the outward displacement of the wall under the earthquake and is prone to damage. It is suggested that the longitudinal and transverse walls of houses should be strengthened and the weakest parts should be reinforced and transformed.