Study Of Wind Load Of The Long-span Open Canopy Structure

The long-span open canopy structures are widely used in stadiums or other large-scale public buildings.These structures,with the characteristics of light mass,high flexibility and small damping,are sensitive to the wind loads,and thus the wind loads generally govern the structural design.The premise of wind resistance design of long-span open canopy structures is to obtain the wind induced pressure on canopy and the shape coefficient.However,the studies on the wind load of long-span canopy with roof opening or wall opening and roof opening are insufficient.In this paper,the numerical simulations of the wind load acting on the long-span canopy with roof opening and long-span canopy with wall opening and roof opening were conducted using the computational fluid dynamics.The characteristics and distribution of the wind induced pressure on the two types of long-span open canopies as well as the influence of some parameters were analyzed.The shape coefficients of the two types of long-span open canopies were given for providing reference in wind resistance design.The main research contents and conclusions are as follows,The numerical simulations of the wind load acting on the long-span ring canopy with roof opening were conducted.The wind induced pressure results of the open roof and closed roof cases were compared,the influences of the inclination angle of the canopy,the roof opening ratio,and the height of the joint between the canopy and the grandstand on the wind induced pressure distribution were analyzed.The results showed that the canopy with roof opening is subjected to the downward wind load,which is more unfavorable to the structural internal force than the canopy with roof closed considering of the self-weight of the structure.The range of two critical inclinations which are of vital influence were determined,and the variation law of the pressure distribution on the canopy with the inclination angle were discussed.The roof opening ratio should not be too small,otherwise the wind load on the canopy will be large.A certain joint height（joint ratio is 1/10）can greatly reduce the wind load on the canopy leeward,but the weakening effect is no longer significant when the joint height continues to increase.The shape coefficients of the long-span open canopy under various working conditions were given for the structural designers as a reference.The numerical simulations of the wind load acting on the long-span membrane canopy with wall opening and roof opening were conducted.The wind induced pressure results of the open roof and closed roof cases were compared,the influence of the substructure existence on the wind induced pressure distribution was analyzed.The results showed that the wind load on the canopy mainly is upward,and the wind load which the windward edge or roof opening edge on canopy are subjected to is large,the upward wind load on canopy in whole is the largest when the wind direction is 45°.Whether the roof opening is closed has a slight influence on the net pressure distribution on canopy.The net negative wind pressure on the canopy windward with substructure is larger than that without substructure,and the difference value of pressure coefficient is about 0.4.the shape coefficients of the long-span open canopy under various working conditions were given for the structural designers as a reference.