Research On Static And Dynamic Characteristics And Human-induced Vibration Of Pedestrian Suspension Bridge In Scenic Spots

Pedestrian suspension bridge in scenic area refers to the bridge built in scenic area for people to walk,which takes the cable as the main load-bearing component of the superstructure of the bridge.Pedestrian suspension bridge is usually a landmark in scenic area.In recent years,it has been widely founded in the whole country due to its relatively low construction investment,attraction to tourists and high economic returns.However,due to the lack of relevant specifications and research results,many pedestrian suspension bridges in scenic spots have become nonstandard projects,causing potential safety hazards.In this paper,the static and dynamic characteristics and human induced vibration of pedestrian suspension bridge in scenic area are studied,and some research results are obtained.(1)Firstly,the development history,structural characteristics and structural system of pedestrian suspension bridge are summarized,and the research status of pedestrian suspension bridge at home and abroad is introduced.The research background and significance of this paper are put forward.The background research is carried out by means of data collection and market research,and discussion of the engineering application status of pedestrian suspension bridge in scenic spot is going on.(2)In this paper,the reasonable completed state of pedestrian suspension bridge is studied.The reasonable cable shape is calculated and determined.The calculation efficiency and reliability of different form finding methods are compared,and the limit state of structure is checked.For the pedestrian suspension bridge with wind resistant cables,form finding of main cable and wind resistant cable respectively can improve the efficiency of calculation.(3)Based on the reasonable completed state of the bridge,five design parameters,i.e.the vertical span ratio of main cable,the inclination angle of wind resistant cable,the rise span ratio of wind resistant cable,the initial prestress of wind resistant cable and the inclination angle of spatial main cable,are selected according to the construction characteristics of pedestrian suspension bridge in the scenic spot,to make analysis.Through the rules gotten,the reasonable range of main design parameters of pedestrian suspension bridge in the scenic spot is summarized.For the most common suspension bridge,the reasonable ranges of parameters are as follows: the vertical span ratio of main cable is 1/10～1/12,the inclination angle of wind resistant cable is 30° to60° and the rise span ratio of wind resistant cable is 1/10～1/15.When there is no wind resistant cable,it can also be replaced by space main cable suspension bridge,and the inclination angle of space main cable should be 30° to 40°.(4)This paper introduces the excitation model used in human induced vibration analysis and the evaluation standards of human induced vibration comfort at home and abroad.In this paper,the field test and finite element simulation are combined to study the human induced vibration response of pedestrian suspension bridge and to make comfort evaluation.By comparing with the test results,the simulation results can basically reflect the test results,and the actual comfort of the pedestrian suspension bridge can be ensured by controlling the calculated peak acceleration in the design stage.(5)The crowd excitation models with different forms and design parameters are selected to analyze the human induced vibration response,and the influence of each parameter on the human induced vibration analysis is obtained.In practical design,the excitation distribution can be set according to the expected vibration mode of the structure,for obtaining the most unfavorable response.For long-span pedestrian suspension bridge,attention should be paid to the influence of crowd added mass.For the crowd excitation of the whole bridge,when the excitation frequency is close enough to the natural frequency,the resonance may occur;when the difference between the excitation frequency and the natural frequency is large,a low frequency mode vibration may be easier to be evoked,and the vibration is small.