| The span of the suspension bridge has been constantly refreshed,and the modem suspension bridge has the tendency to develop longer and bigger.With the continuous increase of bridge span,the cable material utilization and aerodynamic stability of conventional parallel-cable suspension bridge have become especially prominent.Based on the characteristics of carbon fiber and the integrity of space cable,this paper presents a new type of carbon fiber hyperboloid spatial cable system suspension bridge.While utilizing the lightweight high strength and high elastic modulus of carbon fiber material,the space cable system is adopted to improve the bending frequency ratio of the suspension bridge and solve the wind stability problem.The mechanical properties of suspension bridge with the carbon fiber spatial cable are improved by the combination of experiment analysis and finite element analysis.The main work and research results are as follows:The model of the high-strength fiber hyperboloid space cable suspension bridge with the main span of 15m was fabricated,and the vertical load test,the horizontal load test and the model self-vibration characteristic test were studied.It is found that the cable force distribution of the space cable suspension bridge is basically uniform and has good working ability,and with the increase of the load,the vertical displacement under each stage is gradually reduced and the gravity stiffness phenomenon exists.In the vertical eccentric load test,the space cable has better spatial integrity,and the twist angle of the stiffening beam after the eccentric load applied is small,which indicates that the space cable can effectively limit the torsional deformation of the stiffening beam.The horizontal load static test shows that the horizontal component of the internal force of the space cable participates in force and improves the lateral stiffness of the suspension bridge.The experimental model of carbon fiber cable suspension bridge was modeled by ANSYS,and the experimental simulation analysis was carried out.The finite element results and experimental results were in good agreement with each other.In addition,the influence factors of space suspension bridge are studied,and the influence of main elastic modulus,main cable material and elastic modulus of stiffening beam on the mechanical properties of space cable suspension bridge are discussed.The finite element analysis of carbon fiber space cable bridge and parallel cable bridge are carried out.The results show that the vertical stiffness of the hyperboloid space cable suspension bridge is slightly increased and the vertical displacement is reduced by 8.5%under the same load.The torsional angle is reduced by 64%compared with the parallel suspension bridge.The lateral stiffness is reduced by 36.6%,and the mechanical properties of the space suspension bridge are verified.Taking the Qiongzhou Strait Bridge as the background,the span of 4000m space cable suspension bridge and the parallel cable suspension bridge with carbon fiber as the main cable were designed.The static performance,dynamic mode and wind stability of the bridges are studied.The analysis shows that the torsional frequency and the twist frequency ratio of the hyperboloid space cable suspension bridge are greatly improved,and the static wind and flutter stability of the suspension bridge are greatly improved.The critical wind speed of the hyperboloid space system suspension bridge is 109.29m/s,and the critical wind speed of the suspended cable system is 36.14m/s.The flutter critical wind speed of the hyperboloid space system suspension bridge is 172.16m/s,and the flutter critical wind speed of the suspended cable system is 38.95m/s,which shows that space suspension bridge has better wind stability.This paper also makes a preliminary study on the optimization measures of the large span carbon fiber space cable suspension bridge.By analyzing the influence of structural parameters such as central connecting buckle,hybrid fiber and storm rope on the dynamic characteristics,some conclusions which have a certain reference value are coincided. |
