传统民居穿斗式木构架抗震性能振动台试验研究

Shake table test on seismic performance of column and tie wooden structure in traditional residence

为研究西南地区木结构传统民居的抗震性能,对一个位于7度抗震设防烈度地区的两层、两跨穿斗式木构架进行模拟地震振动台试验。试验中选用3条天然波和1条人工波作为输入地震波,对模型结构的动力特性、加速度响应、位移响应、地震剪力及耗能能力进行分析。研究结果表明:随着输入加速度峰值的增加,模型结构自振频率减小,阻尼比增大。在加速度峰值为0.22g的地震作用后,模型结构X向和Y向的一阶自振频率分别降低了10.69%和19.97%,相应阻尼比分别增大到16.06%和17.47%。结构各层加速度放大系数随着加速度峰值的增加而降低,檐柱顶处的加速度放大系数在整个结构中最小,说明檐柱顶处榫卯节点在振动过程中减震作用明显。在加速度峰值为0.22g的地震作用下,结构最大层间位移角为1/53,此时未见模型有显著破坏,表明模型木构架具有良好的整体变形能力和抗倒塌能力。整个试验过程中,一层柱架耗能作用最大,柱脚耗能作用最小。

In order to study the seismic performance of the traditional residences of timber structure in Southwest China,a two-layer and two-span column-and-tie wooden structure in an area with seismic design intensity of 7 degree was tested on shake table,with three natural waves and an artificial wave selected as the input seismic waves.The dynamic characteristics,acceleration response,displacement response,seismic shear force and energy dissipation capacity of the model structure were analyzed.Test results showed that with the increase in input peak acceleration,the natural frequency of the model structure decreased and the damping ratio increased.After the input peak acceleration reached 0.22 g,the first-order natural vibration frequencies in X and Y directions of the model structure were reduced by 10.69%and 19.97%respectively,and the corresponding damping ratios increased to 16.06%and 17.47%respectively.The acceleration magnification coefficient of each layer decreased with the increase in input peak acceleration.The acceleration amplification coefficient at the top of the eaves column is the lowest in the whole structure,indicating that the mortise-tenon joints at the top of the eaves column have apparent damping effect during the vibration process.Under the input peak acceleration of 0.22 g,the maximum inter-story drift angle of the structure was 1/53 and no significant damage was found in the model,implying that the model structure had good deformation capacity and collapse resistance.In the whole test process,the energy-dissipation amount of the first layer and the column root were the maximum and minimum separately.