Equivalent Static Wind Load For Free-Standing Pylon

Wind load is a typical stochastic dynamic load.The interaction between wind load and structure is very complex.In order to simplify this problem,researchers have proposed the concept of equivalent static wind load,which transforms the complex dynamic calculation under wind load into the familiar static calculation for structural engineers.Although the existing equivalent methods achieve multi-objective equivalence,but mainly for building structures,the applicability of the bridge structure needs to be further studied.(1)Aeroelastic model design and vibration and pressure measurement tests are carried out for a mountain bridge tower.According to the wind pressure time history data obtained from the test,the wind pressure time history at the center of each element in the finite element model can be obtained by interpolation with MATLAB.Based on it,the finite element model of the actual bridge tower is loaded and analyzed in time domain.(2)Based on the IWL,the equivalent static wind load of a single target is calculated by means of displacement,internal force and stress wind-induced vibration coefficients.Through the analysis of equivalent accuracy,it can be seen that IWL can be applied to bridge tower structure,and its equivalent accuracy is higher.For the three single objective equivalent static wind loads obtained by three different wind vibration coefficients of displacement,internal force and stress,the equivalent accuracy of load distribution obtained by stress wind vibration coefficients is higher.(3)Based on UESWL,three kinds of equivalent static wind loads are taken as basic vectors,and the combination coefficients of the basic vectors are solved by constrained least squares method to obtain the equivalent static wind load distribution.Through the analysis of its equivalent accuracy,we can see that UESWL is suitable for bridge tower structure,and its equivalent accuracy is higher than IWL.Although the equivalent accuracy of the tower top is low and the single target is low under the individual wind direction angle in the transverse direction of the bridge,it is better than the single target in the overall coincidence with the maximum curve of the transverse response of the bridge tower.(4)The equivalent accuracy and distribution of equivalent static wind loads for multi-objective and three single-objective are compared and analyzed.In practical engineering,considering the factors such as equivalent accuracy,calculation method and solution process,the multi-objective method is more accurate,but the single-objective equivalent method can satisfy the engineering requirements for the structure whose first-order mode of bridge tower plays a major role in the wind-induced vibration response of the structure.