不同设计参数下体育馆大跨度预应力次梁楼盖竖向振动分析

针对大跨度楼盖的竖向振动问题,以某小学体育馆大跨度预应力次梁楼盖为研究背景,改变次梁高度、板厚和平梁底板厚度等结构布置,考虑可能出现的3种荷载工况,采用ANSYS模拟计算各方案楼盖的自振频率及各工况下楼盖的竖向振动加速度,对比分析表明:在工程中,增加楼板厚度对楼盖振动特性以及振动加速度改善效果较小甚至起不利作用;次梁高度增大20%(1 000～1 200mm)、25%(1 200～1 500mm),楼盖基频增大10.4%、12.5%,非类共振时各工况均方根加速度下降率为20.34%～36.14%;增设50 mm厚平梁底板后,楼盖基频较无底板时增大17.6%,非类共振时各工况均方根加速度降幅最大为60.67%;改变平梁底板厚度对楼盖自振频率及振动加速度影响甚微;综合各工况以增设平梁底板改善楼盖振动舒适度效果最佳。

Vertical vibration analysis of long-span prestressed secondary beam roof system in gymnasium with different design parameters

In this paper, a research is conducted into vertical vibration problem for large-span floor based on the construction of the long-span prestressed secondary beam roof in the project of a primary school gymnasium, with the structural arrangement of secondary beam height, floor thickness, and the thickness of the flat beam floor changed. Considering the possible load conditions, the natural vibration frequency and peak acceleration of the floor under three load conditions are simulated by ANSYS. After comparing and analyzing the results, the main conclusions are as follow. The increase of floor thickness has little or even negative effect on the vibration characteristics and vibration acceleration of floor; the secondary beam height increases by 20% (1 000~1 200 mm) and 25% (1 200~1 500 mm), the floor frequency of the floor increases by 10.4% and 12.5%, and the decrease rate of RMS acceleration of non-resonance is 20.34% to 36.14%. After adding 50mm thick flat beam floor, the floor frequency of the floor increases by 17.6% when compared with no floor, and the RMS acceleration decrement is 60.67%for all conditions during non-resonance; however, the effect of changing the floor thickness of flat beam on the natural frequency and vibration acceleration of the floor is minimal; the best effect of adding flat beam floor slab to improve floor vibration comfort is to synthesize each working condition.