Application Research Of Bolt-Shotcrete Increasing Section Method In The Reinforcement Of Masonry Arch Bridge

Due to the low cost and high carrying capacity, Masonry arch bridge has occupied a large proportion in China, especially in mountainous highway. But with the increasing of traffic volume and serious overload phenomenon,which have made different degrees of diseases in masonry arch bridge, and effected it’s bearing capacity. Meanwhile plus its long service life, material weathering, erosion and varying damages of bridge components, affect the performance of the masonry arch bridge. It will cost a lot of money and seriously affect transportation, if removal of these old bridge and construct new bridges. By using appropriate reinforcement technology can restore and improve the capacity of its carrying capacity and prolong its life, Consider the status of there are many masonry arch bridges in mountain area, therefore, it has important significance to research the technology of reinforcement and reconstruction masonry arch bridge.Currently there are many methods to reinforce masonry arch, and in this paper focuses on the study of Bolt-Shotcrete method. After using Bolt-Shotcrete method to extend the main arch-section, causing tensile stress on the combination surface of old and new concrete, for the reasons of concrete shrinkage, creep deformation difference, temperature changes and live load. So the main problem to be solved is how to control the stress level. There are many successful cases about Bolt-Shotcrete with rebar-planting. Planting bar can increase the caring capacity of the construction at on hand, but on the other hand Planting bar will damage the construction. So the strength and durability are also the main concern to everyone. How to ensure the strength and construction quality is also the research content of reinforcement technology. In this paper, take Puzigang bridge as the engineering background of using Bolt-Shotcrete method to reinforce, calculate the forces of the combination structural through finite element software and consider the structural have "second force" to calculate the stress condition of concrete on the combined face and. bridge stage. In addition to controlling the arch section strength checking, shear checking and anchorage steel shear pullout and shear checking, provide a reference for the arch bridge rebar-planting reinforcement calculation.This paper establishes the model of different span arch bridge while the other design parameters are the same and different rise span ratio, the other with the same design parameters by finite element software. Analyze the stress condition of different thickness ofBolt-Shotcrete layer and the original arch stress condition. The result show Bolt-Shotcrete method can obviously reduce the stress of arch bridge, along with the increase of layer thickness, stress value changes slowly of nee-old arch section, so as to determine the optimal anchoring and shotcreting thickness.In this paper using the arch reinforcement effect evaluation methods based on stiffness and evaluation methods based on dynamic characteristics to evaluate the Puzigang bridge which using shotcrete method to reinforcement.