高层胶合木建筑楼盖结构模态试验及振动舒适性评价

Modal test and vibration comfort analysis of high-rise glulam building floor structure

【目的】为了更好地满足高层胶合木建筑楼盖结构的住户居住舒适性等客观要求,提出对其合理评价及减振措施与方法。【方法】本文利用瞬态激励法、环境激励法和频谱识别法分别对同一栋6层胶合木结构建筑的A,B,C三个不同尺寸房屋进行试验模态现场测试研究,对C房间楼盖频谱识别法测试的振动特性进行有限元分析,评价了该胶合木结构建筑楼盖的动力特性和整体振动舒适性。【结果】研究结果表明,A房间楼盖结构的一阶弯曲频率为27.50 Hz,横向二阶弯曲频率为34.75 Hz,纵向二阶弯曲频率为53.25 Hz,一阶扭转频率为56.25 Hz。该房间楼盖底部的加强筋木横梁增大了楼盖结构的横向刚度,但并未抵消纵向排列的胶合木楼盖所导致的各向异性,其楼盖整体的纵向刚度大于横向刚度;A、B、C三个房间楼盖结构的基频值分别为27.5、13和18 Hz,均符合自振频率与跨度的关系式要求,频谱识别法与有限元计算模态分析得到的C房间一阶固有频率非常相符。【结论】胶合木建筑楼盖结构的木横梁起加强其整体刚性作用,并提高了其居住舒适度。由于木质楼板的各向异性,在其宽度方向上设置加强筋木梁尤其重要。该胶合木建筑楼盖整体上满足建筑固有频率规定的舒适度水平要求,瞬态激励和环境激励方式下的试验模态法、频谱识别法,能够有效应用于木建筑楼盖舒适度的测试,具有现实可靠性。

【Objective】To better meet the objective requirements of the living comfort of the residents of the high-rise glulam building floor structure,it is hoped to put forward reasonable use and vibration reduction measures and methods.【Method】In this paper,the transient excitation,environmental excitation and frequency spectrum identification methods were used to carry out experimental modal test in-site on the three different sizes rooms numbered A,B and C of the same 6-storey glulam structural building,and the finite element analysis was carried out on the vibration characteristics of the floor of room C tested by spectrum recognition method.The dynamic characteristics and overall vibration comfort of the glulam building floor are evaluated.【Result】The research results showed that the first-order bending frequency of the floor structure of room A was 27.50 Hz,the transverse second-order bending frequency was 34.75 Hz,the longitudinal second-order bending frequency was 53.25 Hz,and the first-order torsional frequency was 56.25 Hz.The stiffened wood beams at the bottom of the floor of room A increased the transverse stiffness of the floor structure,but did not offset the anisotropy caused by the longitudinally installed glulam floors,and the overall longitudinal stiffness of the floor was larger than the transverse stiffness.The fundamental frequency values of the floor structures of the three rooms numbered A,B,and C were 27.5,13 and 18 Hz,respectively.They all met the requirements of the relationship between natural frequency and span.The frequency spectrum identification method was in good agreement with the first-order natural frequency of room C obtained by finite element modal analysis.【Conclusion】The wooden beams of glued-wood building floor structure play a role in strengthening its overall rigidity and improving the living comfort.Because of the anisotropy of wooden floor,it is particularly important to set up reinforced wooden beams in its width direction.It can be determined that the glulam building floor overall meets the comfort level requirements specified by the natural frequency of the building.The experimental modal method and frequency spectrum identification method under transient excitation and environmental excitation can be effectively applied to the comfort test of wooden building floors,which has realistic reliability.