The Stability Research On The Bridge Of Cable-Self-anchored Suspension Cooperative System

With the rapid development of modern science and technology today, human’scapabilities to across the natural moat and deep chase have far exceeded the former. The cablestayed bridge, suspension bridge and various combinations form of bridges have beenrefreshed the record of the largest bridge span again and again. Varieties of new material andtechnology have made outstanding contributions to the bridge designs and constructions.However, the difficulties and challenges come one after another. In order to improve thestiffness, we need to increase the cross-sectional area of the bridge with the increasing bridgespan, and at the same time, its weight raised, which restricts the bridge span to continue toincrease. To further enhance the spanning capability of the bridge, various combinationsbridge emerges. Cable-stayed—self-anchored suspension bridge is one of them.Combined with the respective advantages of the cable stayed bridge and theself-anchored bridge, the cable-stayed—self anchored suspension bridge makes the structureforce more rationalization and then increase the overall stiffness of the structure and stabilityof wind resistance. But with the high power ultra-statically indeterminate structure of elasticsupport, the cable-stayed bridge and self-anchored suspension bridge under great load allreflect of very strong geometric and material nonlinearity characteristics. In the moment ofthe bending suffer, the stiff girder and bridge tower also suffer the horizontal componentcoming from the suspension cable and main cable and then produce axial force. As a result,the stability of the entire structure will need to consider, but the research of stability of thiscombination system bridge tends to blank.This thesis based on the three tower cable stayed—self-anchored suspension bridge, alsoconsidered the material nonlinearity and geometric nonlinearity factors, and then do theresearch for the stable problems of it.According to establish a finite element model using the finite element analysis softwareMIDAS/Civil, this paper studies on the overall stability of the entire bridge under the deadload and other different loads, then get a conclusion that the overall stability of bridge showsgood and has a high margin under the dead load, vehicle load and wind load. This article alsoresearches the influence of different parameters of bridge system to the stabilities. The result shows that the constraint conditions of the suspension bridge tower and pier have obviouseffect on the stability of the entire bridge, when the tower pier consolidated, the stability ishigher, and when it separated, the stability is lower; the ratio of rise to span of the suspensionbridge section have obvious effect on the stability of the entire bridge, the larger the ratio, thehigher the stability; The height of the stiff girder’s section have obvious effect on the stabilityof the entire bridge, the higher the stiff girder’s section, the higher the stability; The heightand section area of the cable bridge tower have obvious effect on the stability of the entirebridge, the higher the tower and the larger the tower section area, the higher the stability;numbers of suspension cable have effect on the stability of the entire bridge, the more thesuspension cables, the lower the stability; the spacing of the suspension cables has effect onthe stability of the entire bridge, the wider the spacing, the lower the stability.Finally, the author summarizes the overall stabilities of cable-stayed—self-anchoredsuspension bridges and offers some recommendations.