The Reinforcement Technology Of The Suspension Bridge By Combined Cable-stayed Suspension Bridge.

The suspension bridge, with its huge span capacity, fine quake-proof ability, and light and artistic features, is becoming the top choice among the huge span bridge. With the development of the times and the economy, the innovation in the transporting vehicle, the increasing of the car load and speed, greater demand has been raised by people to the safety and cozy of traveling. Compared with the other bridge, the suspension bridge is relatively young, so the great maintenance and strengthening to the suspension bridge is still in a relative small scope. However, the suspension bridge built in the 80s or before has some problems in various degree, because the condition in that time is greatly limited, the span and the load capacity is low, and the vehicle load is increasing and the bridge is becoming old. However, great achievement had been got after the 90s, numerous suspension bridge with distinctive features were built at that time. Besides, most of those bridges are located at the key position in the"five vertical and seven horizontal trunk national highways system", and plays great role in the transporting system. However, as the overloading problem is extremely serious in China, problems are continually arising just few years after coming into service. Thus, great realistic importance is attached to how to strengthen the bridge and improve the load capacity of the suspension bridge economically, rapidly, and practically.As the suspension bridge is still relatively new in China, the attention paid to the importance of the suspension bridge strengthening is not enough. First, this paper collects and sorts out the status of development and the problems rose after being put into service, and then bring out the necessity and urgency of enhancing the load capacity of the suspension bridge. Second, this paper will analyse the factors that affect the safety of the bridge comprehensively. As there is not enough research on the suspension bridge strengthening in China, let alone the relative design material, by summing up the successful method of the strengthening the bridge in foreign countries, this paper will get the conclusion of adopting the method of restoring the damaged main cable, adding assist main cable, altering the hanging system, changing the structural form of the strengthened bridge, adding the suspension cable to form the hanging and stressing assembling and so on.This paper is based on the specific project, and uses the finite element theory to carry out the structural calculation. The relative strengthening method will be brought out according to the calculation results. After selecting the strengthen plan to the Nanpan bridge, this paper will bring out the thought of adding the suspension cable to form the hanging and stressing assembling so that the Nanpan bridge can be strengthened. As the new added cable will be constrained by the former bridge's objective conditions, and considering the influence of the various factors (main cable and main tower structure form) to the choice of the anchoring manner and suspension anchoring area, and make contrast analyze to the working conditions and structure of various anchoring methods, the knowledge towards the suspension bridge strengthening is greatly enhanced.At last, structure calculation will be carried out toward the strengthened hanging and stressing assembling, and comprehensive contrast will be made to the bridge before strengthened. The general stiffness, dynamic performance, and heavy load ability is greatly enhanced, so that the possibility of strengthening the suspension bridge by adding the hanging and stressing assembling is inspected.