Research On Pedestrian Comfort On Footbridge Under Wind Load

With the development of urban modernization and urban tourism,more and more pedestrian bridges are used as landscapes.In order to meet scenic spots of the coastal city,the pedestrian cable-stayed bridges across rivers or lakes also began to increase.Because the wind at the seaside is greater than that in inland cities,and the cable-stayed bridge itself has the characteristics of "light" and "softness",the cable-stayed pedestrian bridge will produce a larger vibration response under the combined effect of wind and crowd loads,thus will cause pedestrian panic and discomfort.At present,there are few studies on this kind of situation at home and abroad.Therefore,based on a seaside cable-stayed pedestrian bridge,the following research is carried out:First,a brief review of the research of the human-induced vibration theory is introduced.According to the relevant results,different models are used to simulate the pedestrian crossing the simply supported beams,and the vibration of the bridge with different models are compared which can provide a basis for the following analysis;Then,the human body model was set at different positions of the sidewalk,and the typical cross-section of the main beam was analyzed by CFD.Variation of the component force coefficient and the lateral position of the crowd on the aerodynamic parameters of the bridge are considered;Finally,based on ANSYS software,the analysis program of human-induced bridge vibration,wind-induced bridge buffeting and human-induced bridge vibration under the cross wind were compiled.The effects of pedestrian density and average wind speed on the dynamic response of the bridge under the combined action of pedestrian and wind load were studied.The results show that: under certain circumstances,the choice of pedestrian load model has similar effect on the dynamic response of the bridge,and the lateral position of the crowd load on the sidewalk has changed the aerodynamic parameters of the main beam section.The vibration of the bridge is relatively large while the crowd is located at the windward side railing.Under the crowd load,the vertical response of the bridge is significantly greater than the lateral response,and the acceleration is related to the 0.5 power of the crowd.However,under the wind load,the lateral response of the bridge is similar to the vertical response,and the acceleration response is related to the square of the average wind speed;under the combined effect of crowd load and wind load,the number of people has a significant impact on the dynamics of the bridge with low wind speed.With high wind speed,The vibration response is greater;therefore,to ensure the comfort and safety of pedestrians,attention should be paid to the wind speed and number of people passing through the bridge.