| Increasing span of suspension bridge is a trend, The spatial torsional rigidity of the traditional parallel cable suspension bridge is small, as span increases, wind-resistant stability of suspension bridges is becoming very prominent. Using hyperboloid characteristics of straight lines, drawing Ivy bridge in Tibet medog, suspension bridge scheme of hyperboloid of spatial cable system is proposed. Using combined experiment and finite element analysis method, the study of on static and dynamic characteristics is conducted to explore the mechanical performance advantages of the new spatial cable suspension bridge compared to the traditional suspension bridge.Test model of suspension bridge of hyperboloid of spatial cable system with oval ring beam is made to conduct experimental study on static and dynamic load of the new spatial cable suspension bridge. Vertical static load test was carried out, with the horizontal static load test, moving vehicle load test and the model vibration test. Through test, the distribution characteristic of cable tension is achieved, the excellent collaborative work performance of space cable is confirmed. The new suspension bridge slightly increases vertical stiffness. The lateral stiffness and torsional rigidity have improved greatly. The wind-resistant stability performance is excellent. With increasing vertical load, the cable tension of the new suspension bridge increases, the gravity stiffness of structure increases, the horizontal force of spatial cable tension increases, the horizontal stiffness of new suspension significantly improves. Through moving vehicle load test, the dynamic displacement and strain response of the new suspension bridge are studied, the performance of large damping and smooth ride of the new suspension bridge is confirmed. Through modal test, we can find the overall stiffness of new suspension bridge has greatly improved.Using finite element software ANSYS to establish three dimensional finite element model to simulate and to analyze the model test. Through the comparative analysis of finite element analysis and experimental results, we find both agree well. In order to further study the loading mechanism of the new suspension bridge, the finite element model of parallel cable suspension bridge with the same parameters is established to analyze comparatively the mechanical characteristic under vertical load, horizontal load and moving load and free vibration characteristics of the structure, we can find new suspension bridge has much better performance to resist horizontal load than parallel cable suspension bridge. Meanwhile, the finite element model of suspension bridge of hyperboloid with circular ring beam is established to analyze comparatively their structural performance, we can find the difference is small.Hyperboloid and parallel cable suspension bridge schemes of the 4000-meter main span are designed, their three-dimension finite element analysis models are established to analyze comparatively static performance under the bridge gravity, live load on car, transverse wind load and the study on free vibration characteristic, static wind stability, and dynamic wind stability is conducted. Through research, we can find the suspension bridge of hyperboloid of spatial cable has good wind-resistant stability and is a possible option for the construction of super large span strait suspension bridge of 3000-5000 m in the future. |
