三向步行荷载作用下钢螺旋楼梯动力响应分析与简化计算方法

Dynamic response analysis and simplified calculation method for steel spiral stairs under three-dimensional walking loads

钢螺旋楼梯因造型轻盈,集建筑美与结构美于一身而广泛地应用于现代建筑中,但由于其自振频率较低,行人步行荷载下可能会产生振动舒适度问题而影响使用。当前对螺旋楼梯的人致振动响应计算中,往往只考虑步行荷载的竖向分量,未明确是否应考虑步行荷载多分量的耦合效应。针对一实际钢螺旋楼梯,采用数值模拟方法,对三向加载与单向加载工况下的楼梯动力响应进行了对比。结果表明,在三向耦合作用下钢螺旋楼梯单向峰值加速度增大10%左右、总体变化幅度在5%左右,实际设计中可采用步行荷载单分量加载计算响应再乘以放大系数的方式考虑三向耦合效应。在此基础上进一步验证了已有的直线型楼梯竖向加速度简化预测方法,表明在一阶模态控制的情况下,该方法可直接用于螺旋楼梯。

Steel spiral stairs is widely used in modern buildings because of its light shape and the combination of architectural beauty and structural beauty. However, with the low natural vibration frequency, vibration comfort problems may be caused under pedestrian walking loads, which will affect its use. In the current calculation of the human-induced vibration response of spiral stairs, only the vertical component of the walking load is often considered. It is not clear whether the coupling effect of the multi-component of the walking load should be considered. Aiming at an actual steel spiral stairs, numerical simulation method was used to compare the dynamic response of the stairs under three-dimensional loading and one-dimensional loading conditions. The results show that the unidirectional peak acceleration of the steel spiral stairs increases by about 10% under the action of three-dimensional coupling, and the overall change range is about 5%. In the actual design, the three-dimensional coupling effect can be considered by using the single-component loading of the walking load to calculate the response and multiplying the amplification factor. On this basis, the existing simplified prediction method of vertical acceleration of linear stairs was further verified, which shows that the method can be directly used for spiral stairs in the case of first-order model control.