Numerical Simulation Of Wind Loads On Long-Span Spatial Structure And Study Of Its Wind-Induced Vibration

Long-span and complex-shape buildings are appearing in the recent years. With the development of national economy and standard of living, the society is in a great need to long-span spatial structures. Long-span spatial structures, light and flexible, are sensitive to wind-induced dynamic excitation, thus wind load frequently acts as controlling external load in the structural design of long-span structures. Those structures are so complicated that the shape factors are not applicable in present building structure load code. The research to wind load characteristics of long-span spatial structures has practical significance.At present, field measurement, wind tunnel test and numerical simulation are the three major methods to study the wind load on the structures. Based on wind tunnel test and numerical simulation by computer, the distribution of wind load, the dynamic response and equivalent wind load factor of the long-span spatial structure subjected to wind excitation were analyzed systematically in this thesis, and some useful conclusions were obtained.Numerical simulation technology based on Computational Fluid Dynamics (CFD) has many advantages, such as adaptable, short-period, low cost. The method becomes more and more important in structural wind project. The flow field around a complex shape building--Hefei Railway Station was simulated by using CFD calculation software FLUENT. The distribution of flow field was analyzed in details. Compared the mean wind pressure coefficient of measuring points calculated in the numerical simulation with the results from the wind tunnel test, it is found that results are in good consistence except parts of corners and cantilever eaves. The above research and analysis manifest that a result meet practical request can be obtained by a reasonable model in the numerical simulation, and the research of wind load in the numerical simulation has highly practical value.Based on FEM and the local mean wind pressure coefficient and time history of fluctuating pressures obtained from rigid model wind tunnel testing, the equivalent wind load factors of a long-span spatial structure were calculated by using FEM calculation software ANSYS. The result indicates that the time history analysis method is rational and effective. Furthermore, it's better to use equivalent wind load factor defined the ratio of wind-induced total displacement to static displacement for computing the equivalent static wind load of long-span spatial structures in the practical project.Using the shape factors and the equivalent wind load factors averaged in different regions of the structure, the wind loads on the long-span spatial structure were calculated for the designers of Hefei Railway Station.