意杨旋切板胶合木正交肋梁箱型楼盖振动特性试验研究

Experimental study on vibration characteristics of poplar LVL orthogonal ribbed box floor

为研究意杨旋切板胶合木(laminated veneer lumber,LVL)正交肋梁箱型楼盖竖向动力特性和人致激励响应规律,对6个足尺箱型楼盖进行了模态测试和人致振动试验。基于振动响应(峰值加速度和加速度振级)结果,分析了箱型楼盖的构造形式和人致荷载工况对楼盖振动响应的影响。结果表明:刨花板(oriented strand board,OSB)厚度、肋梁高度和短肋梁间距分别为18.3、285 mm和600 mm的箱型楼盖具有最大的第一阶自振频率和阻尼比,呈现最优动力特性;箱型楼盖的峰值加速度随着OSB覆面板数量和肋梁高度的增加而减小,随着OSB覆面板厚度和短肋梁间距的增大而增大;随着步频和行走人数的增加,楼盖的峰值加速度逐渐增大;当步频相同时,箱型楼盖在单人跳跃下的峰值加速度比原地踏步或连续行走时的大。提出了箱型楼盖一阶自振频率和在单人行走或跳跃下峰值加速度的计算方法,计算值与试验值吻合良好。

To study the vertical dynamic characteristics and the law of human-induced excitation response of poplar laminated veneer lumber(LVL)orthogonal ribbed box floor,six full-scale poplar LVL orthogonal ribbed box floors were tested by the modal test and the human-induced vibration test.Based on the peak acceleration and acceleration vibration level,the effects of the configurations of the box floor and the human-induced load conditions on the vibration response were analyzed.The results indicate that the box floor with the thickness of the oriented strand board(OSB)slab,the height of the rib beam,and the distance of the short rib beams of 18.3 mm,285 mm,and 600 mm exhibits the largest first-order natural vibration frequency and damping ratio,as well as the best dynamic characteristics.The peak acceleration of box floors decreases with increasement of the OSB slab numbers and the height of rib beams,whereas it increases with increasement of the thickness of OSB slabs and the spacing of the shorter rib.The peak acceleration increases with increasement of the stride frequency and the number of people walking.When the stride frequency is the same,the peak acceleration of the box floor under the one-person jumping is larger than that of stepping in place or continuous walking.The calculating method for the first-order natural frequency and the peak acceleration of the box floor under one-person walking or jumping are carried out,and the calculated results agree well with the experimental results.