历史文化建筑砖木混合结构原位动力特性试验及地震响应分析

IN-SITU DYNAMIC CHARACTERISTIC TEST AND SEISMIC RESPONSE ANALYSIS OF HYBRID BRICK-CONCRETE AND TIMBER STRUCTURE OF HISTORIC AND CULTURAL BUILDINGS

  • 摘要: 为研究历史文化建筑砖木混合结构的动力特性及地震响应,进行原位动力特性试验,采用峰值拾取法计算结构自振频率和振型。考虑二层木结构和一层砖混结构的动力特性和相互作用,建立了混合结构有限元模型,计算得到的频率和振型与试验结果吻合较好。输入不同幅值的Kobe波、El Centro波和人工波,进行位移响应及加速度响应分析。结果表明:砖木混合结构1阶、2阶自振频率为4.278 Hz、4.375 Hz,振型分别为平动(东西方向)和平动(南北方向)。8度多遇地震下结构的峰值位移较小,而设防和罕遇地震下,结构位移响应明显增加。罕遇地震下,二层木结构柱头最大位移是一层砖混结构柱头最大位移的6.12倍,最大层间位移角为1/155小于规范限值。二层柱顶和屋顶的最大加速度响应较大,而一层柱顶较小。整体结构动力系数小于1,结构的减震性能较好。

     

    Abstract: In order to study the dynamic characteristics and seismic response of the hybrid brick-concrete and timber structure of a historic and cultural building, in-situ dynamic characteristic test was carried out and the peak picking method was used to calculate the structural natural frequencies and vibration modes. Taking into account the dynamic characteristics and interactions between the second-floor timber structure and the first-floor brick-concrete structure, a finite element model of the hybrid structure was established and the calculated natural frequencies and vibration modes were in a good agreement with the test results. Kobe, El Centro and an artificial wave of various amplitudes were input for displacement and acceleration response analyses. Experimental results show that the first, second and third order natural frequencies of the hybrid brick-timber structure are 4.327 Hz, 4.375 Hz and 5.875 Hz, and that the vibration modes are translation (east-west), translation (north-south) and torsion, respectively. The peak structure displacement is small for the 8-degree frequent earthquake, while the displacement response increases significantly for the design and the rare earthquakes. The maximum displacement of the column top of the second-floor timber structure is 6.12 times the maximum displacement of the column top of the first-floor brick-concrete structure. The maximum interlayer displacement angle of 1/155 is less than the code limit. The maximum acceleration response is larger for the tops of the second-floor columns and the roof, and less for the tops of the first-floor columns. Dynamic coefficients of the overall structural is less than 1 and the structure has a good seismic mitigation performance.

     

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