漾濞6.4级地震受损穿斗木结构农房振动台试验

Shaking table test of damaged Chuan-dou timber structure rural houses in Yangbi M_(s)6.4 earthquake

2021年5月21日大理漾濞6.4级地震中大量传统穿斗木结构农房遭到破坏。首先对灾区大量现役的传统穿斗木结构土墙围护房屋进行建筑结构概述,然后利用已有的二层穿斗式木结构模型,采用黏弹性阻尼器加固木构架榫卯节点,通过输入此次地震中漾濞台(距震中7.9 km)记录到的EW向地震波开展振动台试验,最后,结合农房实际震害,在分析试验结果基础上归纳总结房屋震害规律和加固效果。研究结果表明:木结构模型能较好地反映漾濞地区该类房屋在地震中的振动特性,模型各层刚度和阻尼呈竖向不规则分布,木构架横向整体性高于纵向,层间耗能纵向以二层为主,横向比较均匀。无阻尼模型整体加速度放大系数在0.92~1.43之间,位移响应在输入地震动不大时以剪切变形为主,高烈度输入时弯曲变形增加,模型在加载过程中基本完整,满足大震不倒的要求。阻尼器可为榫卯节点提供附加刚度和阻尼,安装阻尼器后模型各层耗能能力增强,测点位移响应峰值明显减小,试验范围内,输入地震动越大,层间位移角降低越显著。

A large number of traditional Chuan-dou timber structure rural houses were damaged in the Yangbi M_(s)6.4 earthquake in Dali on May 21,2021.In this paper,firstly,an overview of the architectural structure of numerous traditional Chuan-dou timber frame rural houses with surrounding earth wall in service in the disaster area was given.Then,by inputting the EW directional seismic wave recorded by Yangbi station(7.9 km from the epicenter)during the earthquake,the shaking table test was carried out on the existing two-story Chuan-dou timber structure model.At the same time,the viscoelastic dampers were used to strengthen the mortise-tenon joints of the wooden frame.Finally,combined with the actual seismic damage,the earthquake damage law and reinforcement effect of the rural houses were summarized on the basis of analyzing the test results.The results show that the timber structure model can well reflect the vibration characteristics of this kind of houses in Yangbi area.The stiffness and damping of each layer of the model are distributed irregularly in vertical direction.The transverse integrity of the wooden frame is higher than that in the longitudinal direction,the inter-layer energy consumption is dominated by the second layer longitudinally and is more uniform horizontally.The overall acceleration amplification coefficient of the undamped model is between 0.92 and 1.43.The displacement response is mainly shear deformation when the input ground motion is small,and the bending deformation increases when the input ground motion is high.The model is basically intact in the process of loading and meets the requirement of not collapsing under a major earthquake.The damper can provide additional stiffness and damping for the mortise-tenon joints.After installing the damper,the energy dissipation capacity of each layer of the model is enhanced,and the peak displacement response of the measuring point decreases obviously.In the seismic intensity range of the test,the larger the input ground motion is,the more significant the inter-story displacement drift decreases.