聚丙烯打包带网水泥砂浆面层加固残损砖箍窑洞振动台试验研究

Shaking table test on damaged brick hoop caves strengthened by cement mortar coating with polypropylene packing belt meshes

为提高残损砖箍窑洞的抗震性能,对黄土高原地区典型传统民居砖箍窑洞残损试验模型采用墙体裂缝注浆加固和聚丙烯打包带网水泥砂浆面层进行整体抗震加固,并对加固后结构模型的抗震性能进行模拟地震动振动台试验。试验中选取人工波、El Centro波和LA-Hollywood波作为地震动输入,实测并分析了加固结构在地震作用下的自振频率、阻尼比、加速度响应、位移响应、扭转效应、基底剪力、滞回耗能及加固效果。结果表明:随着地震动峰值加速度的增加,模型结构的自振频率和刚度下降,阻尼比增大;随地震动峰值加速度的增加,X向、Y向加速度放大系数均逐渐减小,出现明显损伤后,结构动力放大系数减小幅度变大;多遇地震作用下加固模型结构最大层间位移角为1/500,设防地震作用下最大层间位移角为1/200,罕遇地震作用下最大层间位移角为1/133,倒塌时最大层间位移角为1/29;拱脚与基础的相对变形明显大于拱顶及窑顶的;加固模型结构破坏时水平扭转角最大值为0.0015 rad,具有较大的抗扭刚度和耗能能力;综合加固后结构模型的抗震性能、能量耗散、经济性,聚丙烯打包带网水泥砂浆面层加固砖箍窑洞具有明显的优势,可在残损砌体结构的抗震加固中推广应用。

In order to improve the seismic performance of damaged brick hoop cave and study the seismic performance of the typical traditional dwelling brick hoop caves in loess plateau strengthened by grouting and cement mortar coating with polypropylene packing belt meshes,a shaking table test of scale model under simulated earthquake excitation was conducted.In the test,artificial wave,El Centro wave,and LA-Hollywood wave were selected as seismic input.The natural frequency,damping ratio,acceleration response,displacement response,torsional effect,base shear force,hysteretic energy dissipation and retrofitted effect of the structure under earthquake were measured.The results show that with the increase of peak ground acceleration,the natural frequency and stiffness of the model structure decrease,the damping ratio increases.With the increase of the peak acceleration,the amplification coefficient of both X and Y direction acceleration gradually decreases.After obvious damage occurs,the structural dynamic amplification coefficient decreases to a larger extent.For frequent earthquakes,the maximum inter-story drift ratio of the strengthened model structure is 1/500.For design basis earthquakes,the maximum inter-story drift ratio is 1/200.For maximum considered earthquakes,the maximum inter-story drift ratio is 1/133,and for collapse,the maximum inter-story drift ratio is 1/29.The relative deformation of the arch footing with foundation is greater than the relative displacement of the arch and cave roof.The maximum value of the horizontal torsion angle is 0.0015 rad when the strengthened model structure is destroyed.The strengthened model has strong torsional stiffness and energy dissipation capacity.Based on the seismic performance,energy dissipation and economical analysis of the reinforced structure model,it is found that the brick hoop cave strengthened by cement mortar coating with polypropylene packing belt meshes has obvious advantages,which can be extended and applied in the seismic retrofitting of the damaged masonry structure.