Local Force Bearing Test Of High Strength Stirrup Confined Concrete

The integrity and safety of long-span bridges are closely related to the mechanical transfer process of local structures.The force analysis and design application of the main region has been very mature,while the stress and strain distribution in local area is scattered,and the deformation coordination condition is difficult to apply.Based on the theory of plastic limit analysis,this paper puts forward the bearing model of local force bearing structure of bridge under the action of axial force,and obtains the upper limit solution formula of local bearing capacity.Through laboratory tests,local bearing strength tests of concrete samples confined by stirrups of 1570 MPa and HRB400 were carried out.The ultimate bearing capacity of local bearing capacity is obtained Compared with the design value of ultimate bearing capacity obtained by the upper limit solution formula,the actual ultimate bearing capacity of stirrup confined concrete specimens is 6%?19% higher than that calculated by the upper limit solution formula With the same reinforcement ratio,the bearing capacity of 1570 MPa stirrup is 1.7 times higher than that of HRB400 stirrup The bearing capacity increases with the increase of reinforcement ratio.At the sametime,the results of local shear failure tests show that the failure mechanism of the sample is consistent with the hypothesis,and the shear bearing capacity of the structure can be greatly improved by high strength stirrup,which provides an idea for the application of high strength stirrup in local shear structure.Combined with the local regional design of Matan Hongshui River Bridge,the local bearing capacity formula is used to check the bearing capacity of arch seat concrete.At the same time,the bearing capacity of cushion stone concrete is checked and calculated.By using different safety factor,local bearing capacity formula can be used for the analysis and design of local area.The application of the research results strengthens the connection design and provides integrity and safety guarantee for the main structure to give full play to its carrying capacity.