工业管架风荷载的遮挡效应显著,现行规范风荷载取值安全性、合理性急需进行评估。以石油化工厂区常见的管架、裂解炉为对象,采用测力(high frequency force balance,简称HFFB)风洞试验和测压(high frequency pressure integration,简称HFPI)风洞试验,研究了工业管架风荷载的遮挡效应,并通过与现行规范对比,给出了规范的适用范围。通过测压风洞试验,给出了外围管架遮挡下内部封闭设备的遮挡系数,利用该系数能够扩大现行规范中整体方法的适用范围。分析结果表明:现行规范提供的工业管架风荷载确定方法是偏于安全的,对于管架及支撑管道的管架,整体方法得到的风荷载与测力风洞试验吻合较好;由于未考虑管架对内部封闭设备的遮挡效应,按现行规范得到的裂解炉风荷载明显偏大。
With the opening of ancient Tibetan structures to visitors worldwide, human load has become the principal live load on these structures. This project studies the properties of the floor structure of an ancient Tibetan building and its behavior under human-induced load effects. Tests were conducted with static and dynamic crowd load, including stepping and jogging by people at a fixed position. The tests show that the floor structure does not behave as a continuous slab. It takes the load from local areas with minimal load transference properties. The acceleration response shows significant peaks when the footstep frequency is close to the natural frequency of the s~＇ucture, but the human jogging excitation frequency does not have any obvious effect on the structural response. The elastic modulus of the Agatu material is estimated to be close to zero from the measured natural frequency of the slab. The Agatu material is concluded to be a discrete compacted material with insignificant contribution to the structural rigidity of the floor slab.
