Research On Box-shaped Arch Bridge Strengthed By The Enclosed Reinforced Concrete

After years of operation,the box arch bridge has been designed with a low technical standard and long-term overload operation,resulting in a series of diseases that result in insufficient carrying capacity.In order to avoid the expensive cost of the old bridge demolition and reconstruction,it is necessary to explore a reinforcement method suitable for the box arch bridge to strengthen it.In this paper,a box arch bridge is used as the engineering background to explore the best solution for reinforced box arch bridge by ferrule method.The main work and conclusions are as follows:1.The structural characteristics of the box arch bridge and the development history at home and abroad are summarized.Combined with the operation status of the in-service box arch bridge,the common diseases of the components in the structure and the corresponding reinforcement methods are discussed.It is found that the reinforced concrete hoop reinforcement technology has been proposed for nearly 20 years and has good reinforcement effect.However,the influence of the thickness of the ferrule layer and the ferrule area on the reinforcement effect in the reinforcement of the box arch bridge is not much.2.Taking a box arch bridge as the research object,the original bridge model was established by Midas civil and subjected to force analysis.The analysis results show that the bearing capacity of most sections of the bridge is not up to standard,and the deflection in the mid-span is large,which needs to be reinforced.3.The reinforcement technology of reinforced concrete ferrule closed main arch ring is summarized,and its reinforcement mechanism and construction technology are summarized.Then the control variable method is used to analyze the influence of two different factors of the thickness of the ferrule layer and the ferrule reinforcement area on the reinforcement effect.The results show that the 20 cm ferrule layer can be used to strengthen the area between the arch and the third column.The best reinforcement effect can reduce the cost and shorten the construction period.4.According to the analysis results,the optimal ferrule thickness and ferrule area are cast into the 20 cm thick ferrule layer between the arch and the third column,and the Q345 steel plate with a thickness of 10 mm is affixed to the left and right sides of the lower edge of the arch.The reinforcement scheme is used to establish a reinforced finite element model and perform force analysis.The comparison of the bearing capacity of the bridge before and after reinforcement and the comparison of static and dynamic load analysis results show that the scheme can significantly enhance the stiffness of the bridge and effectively improve the dynamic characteristics of the structure.It can provide verification reference for related projects in the future.