New Technology Of Continuous Bridge Deck Reconstruction Of Double Arch Bridge

Rebuilding bridge deck is a feasibly economic method for the double arch bridge whose main structure is good and whose bridge width can satisfy the requirement of traffic now and in the future.The bridge deck of continuously reinforced concrete plus asphalt concrete pavement is introduced into the reconstruction design of bridge deck of double arch bridge by the bridge engineering research institute in Hunan University, overcoming the insufficiency mechanical behavior of traditional bridge deck of double arch bridge. It is the first to apply bridge deck of continuously reinforced concrete into reconstruction design of bridge deck of the double arch bridge in China, so this paper focuses on the impact of this new formation technology on the continuous bridge deck and the main structure of double arch bridge. The main contents are in the followings:(l)Using bridge finite element calculation software Midas Civil, the naked arch model and the complete bridge model with the structure on crown and bridge deck of the double arch bridge are established. When modeling, according to the finite element theory and mechanical feature of the parts of existing bridge,constitutive relation of the material, form of the cross-section, element type and reasonable boundary condition is chosen to simulate. And it verifies the finite element modeling in this paper by the error amount between the finite element calculation value and the measured value of the longitudinal steel stress in the continuously concrete bridge deck caused by temperature deformation of the main arch.(2)The accessional internal force and deformation of the main arch ring of the double arch bridge under the action of temperature after using continuous bridge deck reconstruction technology is analyzed. It can be indicated by the comparison analysis on the accessional internal force and deformation of the main arch ring before and after reconstruction:the restriction of continuous bridge deck will not enlarge the bad impact of accessional internal force on the main arch ring by temperature. Additionally, the dynamic performance of the double arch bridge using continuous bridge deck reconstruction technology is analyzed, and the ration between the previous fifth natural vibration frequency of main bridge after reinforcement and frequency before reinforcement is about1.03, showing that the continuous bridge deck strengthens the integral rigidity of double arch bridge. (3)By embedding strain gauge in the continuous bridge deck, the strain data are observed and collected in18months, and then analysis is conducted on the data of the field test and it can be known by comparison between this data and the results of finite element calculation model that:the maximum tension strain of section occurs above each top of the pier under the action of temperature change of the main arch ring, and the maximum tension stress of longitudinal steel is119.8MPa. Though some transverse cracks occur in the concrete of the bridge deck under the action of temperature change, the width of the crack is decreased gradually later with the increase of temperature. The observation in the field shows that no reflection crack occurs in the the asphalt concrete surface.(4)Based on the main mechanical performance of double arch bridge and the continuously reinforced concrete bridge deck, the construction key points of the continuous bridge deck technology to reform the double arch bridge are summarized.