冷弯薄壁型钢-混凝土组合楼盖振动性能试验研究

Experimental study of vibration behavior of cold-formed steel concrete composite floor

对构造不同的四块足尺比例冷弯薄壁型钢-混凝土组合楼盖模型进行振动性能的动载试验。在正常使用阶段,研究压型钢板与冷弯薄壁型钢梁连接的螺钉间距、刚性支撑件、楼盖端部约束条件等构造设置和楼面活荷载对组合楼盖自振频率的影响。研究表明:组合楼盖的自振频率随楼面活荷载的增加而降低;减小压型钢板与冷弯薄壁型钢梁连接的螺钉间距、相邻楼盖梁的跨中位置设置刚性支撑件及加强楼盖端部约束均能提高组合楼盖的自振频率。采用ANSYS有限元程序对试验模型24种荷载工况的振动性能进行模态分析,有限元模态自振频率与试验自振频率吻合较好。提出的理论公式能够较好预测组合楼盖的自振频率。在正常使用阶段荷载标准组合下,建议组合楼盖的自振频率不小于10Hz。

Four full scale cold-formed steel composite floors with different patterns of configuration were dynamically tested to study the vibration behavior.In the service stage,when the space between screws connect the profiled steel sheet and the cold-formed steel joists were changed,or the rigid blocking,end constraints,floor live load were different,effects to the fundamental frequency of composite floor were studied.The study shows that the fundamental frequency declines with the increase of the floor live load,and the fundamental frequency can be improved by reducing the space between screws,setting rigid blockings at mid-span of adjacent joists,or strengthening the floor end constraints.Through modal analysis of the vibration behavior of the experimental mode under 24 load cases with ANSYS FEM,the FEM results are in good agreement with the experimental results.Finally,a formula to forecast the fundamental frequency preferably is proposed.Under nominal combination of loads during service stage,10Hz is suggested as the fundamental frequency of the composite floor.