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对3个大型火车站雨棚进行风洞测压试验,分析结果表明开放式雨棚受站房影响较大,在不同风向下可能形成“上吸下顶”的受力特征,造成局部风压幅值的增加。由于风压分布不均匀和尾流区范围大等原因,体量较大的雨棚平均整体风吸力系数在-0.25左右,远小于小体量的雨棚,且基底竖向反力的变化范围也比较小。结合测压时程,采用广义坐标合成法计算了雨棚的风振响应,着重指出由于雨棚整体风压基本上是风吸力,因而对应最大竖向反力的风振系数可能出现负值或很高的正值,导致得出的等效静风荷载不合理,此时采用附加风振力法可得出更符合实际情况的等效静风荷载。
Wind tunnel pressure test was carried out on three large railway canopy shelters. The analysis results show that the open shelter is greatly affected by the station building, and the force characteristics of “upper suction and lower roof” may be formed under different wind directions, resulting in local Wind pressure amplitude increases. Owing to the uneven distribution of wind pressure and the large wake area, the average overall wind suction coefficient of a large-sized canopy is about -0.25, which is much smaller than that of a small-sized canopy. The variation range of the vertical reaction force of the foundation Also relatively small. Combined with the time history of measurement, the wind-induced response of the canopy is calculated by generalized coordinate method. It is emphasized that the wind-induced vibration coefficient corresponding to the maximum vertical reaction force may be negative due to the fact that the overall wind pressure in the canopy is basically the wind suction force. The high positive value leads to the unreasonable equivalent static wind load. At this time, the additional wind vibration force method can be used to obtain the equivalent static wind load that is more in line with the actual situation.