Double Arch Bridge Disease Analysis And Reinforcement Treatment Research

The double curved arch bridge plays an important role in the history of bridge construction. But, with economic development, traffic volume and vehicle load increased. The double curved arch bridge's shortcomings which were low design load, poor structural integrity and inadequate reinforcement appeared obviously. So it couldn't meet today's traffic requirements. In this paper, the total technical condition of the existing double curved arch bridge was assessed by investigation, experiment and finite element analysis. The whole performance was judged in normal state and limit bearing capacity. And the reinforce project of structure was put forward to extend the service life of bridge. The main content is as follows:(1) To analyze the bridge structural damage reasons in many aspects. The common diseases of double curved arch bridges are in main arch, arch, pier and foundation, floor system and accessory structure. The causes of concrete bridge structural damage were analyzed to provide a basis for investigation of bridge disease and damage evaluation.(2) Combined with the engineer example of Jiao River Bridge, this paper studied the bridge diseases by observation, Structure size checking, investigation of construction materials strength and crack distribution. The technology state estimation was made based on JTG H11-2004 "specification for maintenance of highway and bridge".(3) The results which included bearing capacity, load test and finite element analysis showed that the bearing capacity of crown section was able to meet requirements of Highway levelⅡload, but the bearing capacity of spring section couldn't meet requirements of Highway level II load, which need be reinforced. The measured values of crown stress were close to the calculated results, which proved the theory calculating model was correct. The stages I was in the elastic region under experimental load, the stages II was in the inelastic region. The measured values of deflection were less than the calculated results. The overall structural force was well under experimental load, but the security reserve was not surplus.(4) Dynamic load test illuminated that the measured values of first-order frequency from modeling experiment were close to the calculated results, but the bridge deck damaged badly. The impact action was obvious when vehicles went through the bridge. Vibration was larger in both horizontal and vertical directions, and vibration was also significant. It showed that the whole security reserve was lower.(5) From static and moving load experiment, the strengthening methods were proposed for main arch ring, solid-web section, horizontal tie beams, columns and column covers on the arch beam, abdominal arch, bridge deck, etc. To ensure the bridge was safe in normal state and limit bearing capacity.