The Damage Analysis And Reinforcement Measures Of The Existing Prestressed Concrete Trussed Combination Arch Bridge

The combined truss arch bridge is applied into the mountain area widely because of the merits of low cost, large spanning ability and simple cantilever assembly construction. With the growth of the bridge service time, the prestressed concrete truss arch bridge appears a large number of diseases, and the diseases severely affect the use of this type of bridge. So, this paper has done some work to analyze the reason for diseases and the effective reinforcement of the bridge.A large number of the prestressed concrete truss arch bridges are investigated, and some common diseases are analyzed and summarized. It is found that the bridge deck, the solid-web section side wall and bottom plate, the transition area between hollow-web and solid-web easily appear the cracks. The finite element software ABAQUS is used to establish the three-dimensional solid finite element model of the bridge, and the structure stress under the variety of working conditions is analyzed, such as temperature stress, vehicles load and prestress. The weakest areas of the bridge are analyzed by the stress nephogram, and the stresses of the representative members under the different load are discussed by drawing stress curves. Based on the principle of birth-death element, the work process of the bridge is simulated when some local parts quit work due to overstress. Besides, the priorities in disease fatal levels of the different areas and the correlations between diseases are analyzed. Finally, based on the above analysis, some effective reinforcement measures are proposed, and the stress of the bridge after reinforcement is analyzed.The results show that the finite element model simulates the actual diseases of the bridge well. The related components near the transition area between hollow-web and solid-web under dead load appear overstressing. The effects of temperature stress and vehicles load on the stress of bridge are significantly greater than other loads. Besides, the crack damage of bridge deck leads to the disease of box clapboard. The full renovation of bridge deck, the increase in the number of wedge member and section enlargement of solid-web bottom can effectively solve these problems, such as the crack damage in bridge deck, the crack in transition area between hollow-web and solid-web, overstress of floor deck of solid-web and so on.