钢桁架大跨度、大悬挑结构楼板舒适度分析

Comfort Analysis of Steel Truss Large-span and Large Cantilever Structural Floor Slabs

某项目采用钢桁架结构体系,竖向落地支撑点少,最大跨度近40 m,悬挑长度达到9 m。项目大跨度水平支撑体系采用中间主跨桁架+边桁架的构造形式。为避免大跨度楼盖在使用过程中出现振动舒适度缺陷,项目借助MIDAS Gen软件对该楼板的舒适度进行了分析,并根据模态分析找到振动最不利位置,进而通过对最不利振动点添加步行荷载进行时程分析,控制峰值加速度,使其满足《建筑楼盖结构振动舒适度技术标准:JGJ/T 441—2019》[1]限值要求。各项验算结果表明此钢桁架体系的第一自振频率及峰值加速度均能满足文献[1]要求,舒适度情况较好,可以在后期使用过程中有良好的体验。

One certain project uses a steel truss structural system with a few vertical support points,with a maximum span of nearly 40 m,and a cantilever length of 9 m.The long-span horizontal support system of this project adopts the structural form of middle main span truss+side trusses.In order to avoid vibration comfort defects during the usage of long-span floors,the project uses MIDAS Gen software to analyze the comfort of the floor,and finds the most unfavorable vibration positions based on modal analysis,and then adds the most unfavorable vibration points to the walking load,which is analyzed in time history,and the peak acceleration is controlled to meet the specification limit requirements.Various calculation results show that the first natural frequency and peak acceleration of this steel truss system can meet the specification requirements,and the comfort is good,thus you can have a good experience in the later use process.