Study On Wind Resistance Of Limit State Response Of Long-span Roof Structures Considering Wind Direction

The long-span roof structures have the characteristics of light weight,high flexibility,small damping and dense vibration modes.The natural frequency of the structure is getting closer to the excellent frequency of strong wind,and it is very sensitive to the effect of wind loads.All of these pose great challenges to the wind-resistant design of long-span roof structures.It is urgent to re-verify the rationality of the existing wind-resistance theory of long-span roof structures and develop a more elaborate wind-resistant design theory.In order to evaluate the wind resistance of long-span roof structure more reasonably and improve the reliability of wind resistance system of long-span roof structure.In this thesis,several key problems in the theory of wind resistance analysis of long-span roof structures are studied.The main contents and results are as follows:(1)An improved independent storm method is proposed.This method takes into account the accuracy and efficiency of independent storm value selection.For the traditional method of selecting the peak value of independent storms——the block method,which cannot accurately select the peak value data of independent storms.Some important independent storm values will be omitted,which will affect the estimation of extreme wind speed in the recurrence period.The improved method proposed in this thesis——the slider method,which can quickly and accurately select independent storm values.It provides more reliable data for estimating extreme wind speed and calculating extreme response.(2)A method considering the correlation of wind direction is proposed,which is between the independent method and the independent method without considering the direction factor.It is more reasonable to show the correlation between wind speed and wind direction.In actual engineering,the annual maximum wind speed of each wind direction can be regarded as independent of each other for the convenience.However,if it is required to deal with this problem more elaborately,the direction of wind speed and the correlation between wind directions should be considered.And this will make it more reasonable.(3)Wind tunnel tests and finite element analysis are used to analyze the structural response.We can get the response of different wind speeds and the structures under different wind directions.The relationship between the extreme response coefficient and the average wind speed is a power exponential relationship,which simplifies the calculation of the extreme value response of the return period.Through the analysis of engineering examples,the fitting effect of the curve is better,and other functions can be used for fitting according to the actual engineering conditions.(4)By comparing the estimated values calculated by the maximum value of the 16 wind directions,sector-by-sector(SBS)method,independent assumption of wind directions and wind speed and the method of considering the direction wind speed correction.The method of considering the direction wind speed correction is more precise,and the result is more reasonable in this paper.In the case that the return period is very large,the difference between the two methods is not very large,and it tends to be more and more consistent.If you need simple calculation in actual engineering,you can use the method of completely independent assumption of wind directions and wind speed,which is more convenient.If we have a more elaborate calculation,when we consider the direction factor,we can see that the value calculated by the method of considering the direction of wind speed correction is more reasonable.Wind resistance optimization design of long-span roof structure based on probability performance is realized.The comprehensive wind resistance of long-span roof structure is improved.