Strengthening of Interlocking Steel Pipe Pile Cofferdam Used in Main Pier Foundation Construction of Guanzhanhe River Bridge in Chongqing
The main bridge of Guanzhanhe River Bridge in Chongqing is a three-span continuous rigid-frame bridge with a main span of 110 m and two side spans of 62 m.The interlocking steel pipe pile cofferdam was used to facilitate the construction of the main pier foundation.During the construction of the cofferdam,the normal water level was+325.300 m and the control water level was+330.500 m.When the interlocking steel pipe piles circling the cofferdam were driven into position and the first four layers of inner supports were installed,the extreme weather induced the water level to rise and reach+332.200 m,posing a threat to the safety of the cofferdam.In order to solve the safety problem of steel pipe pile cofferdam,the reinforcement scheme of installing internal support under underwater condition is proposed.After the internal water head of the cofferdam is consistent with that of the outside,the locked steel pipe pile is raised to the elevation of+334.000 m,the previously-installed 4 internal supports are removed,and another 6 internal supports are installed.The finite element models of the steel pipe pile cofferdam before and after the strengthening were built up in MIDAS Civil to analyze the load bearing safety and stability of the steel pipe piles and inner supports.It is shown that at a control water level of+330.500 m,the maximum normal stress of the cofferdam fell from+330.500 m before strengthening to 82.3 MPa after strengthening,decreased by 49.3％.The load bearing water level rose from the control level of+330.500 m to the target control level of+333.500 m,leaving the cofferdam with a strength and rigidity margin.To install the inner supports in water can improve the load bearing capacity of the cofferdam.For the Guanzhanhe River Bridge,the cofferdam of the main pier exhibited good load bearing capacity after strengthening,and the subsequent pile cap pour was carried out smoothly.
rigid-frame bridgeinterlocking steel pipe pile cofferdamstrengtheningfinite element methodbridge construction
万方数据
维普
