The Reinforcement Technology Of Multi-Span Reinforced Concrete Double-Ribbed Box Arch Bridges

Multi-span reinforced concrete rib arch bridges have the characteristics of beautiful shapes,convenient construction,low cost and large capacity.They are very widely applied in our country.Many multi-span reinforced concrete box arch bridges have been built,most of which have different degrees of diseases.they can not meet the needs of today’s social transport.So it has great significance to study the reinforcement method of multi span reinforced concrete rib arch bridge.After summarizing the research work of bridge reinforcement inside and abroad,this paper summarizes the common diseases of reinforced concrete rib arch bridge,and analyzes the causes of the diseases.Then,the reinforcement technology of reinforced concrete rib arch bridges is studied,and the technical characteristics of the main components of reinforced concrete rib arch bridge are summarized.This paper takes the Xijiang Bridge in Tengxian reinforcement project as an example.Before reinforcement,the bridge was examined by appearance,load test,cause analysis and internal force checking.At the same time,this paper puts forward the reinforcement scheme that the main arch ribs are reinforced by concrete and local components are reinforced by steel plate and so on.In this paper,the finite element model of the Xijiang Bridge is established by MIDAS/Civil and ANSYS finite element software.The Internal force calculation,stress analysis and overall stability analysis are carried out respectively.The beams and columns are analyzed separately.The results show that under constant load,the bending moment of the main arch rib increases by 6.9%and the axial force increases by about 10.2%.Under normal working conditions,the bending moment and axial force increased by about 9.2%,but the compressive stress of arch foot was reduced by 15.54%,and the crown be changed from tensile stress to compressive stress with no crack.The stress of the reinforced concrete member is reduced,and the maximum tensile stress is reduced by 29%.The load carrying capacity of the bridge increases by 18.4%.It can be seen that the reinforcement effect is ideal,which provides the theoretical data for the reliability of the design.After the reinforcement,the appearance test and load test of Tengxian Xijiang bridge are carried out.It was found that the new disease was not found after the reinforcement of the bridge.The results of load test show that the bearing capacity of the bridge could meet the design requirements.Under the same working condition in 19th span and 20th span,the deflection of the same position is 47.1%and 68.3%of original value.The strain is about 62.5%and 77.2%of original value.The stiffness and stability of the reinforcement are improved significantly,which verifies the validity and reliability of the reinforcement scheme.The research results of this paper can provide some reference for the design of reinforced concrete multi ribbed box arch bridge.