Research The Application Of New Materials In A Bridge Concatenation

The old and new concrete bridge mosaic is often used in the highway widening project,and has been applied in many projects in China in recent years.The stress condition of bridge joint segment is complex,and it needs to bear greater stress and deformation.The concrete material has poor tensile and deformation ability,and the concrete in the splicing section is easy to crack during use.It is necessary to use materials with good ductility and high strength,to change this situation.ECC and MMA materials have high tensile strength and good ductility,and are suitable for bridge splicing.This paper mainly studies the application of ECC and MMA materials in bridge splicing section.Firstly,the preparation methods of ECC and MMA are introduced,and the corresponding mechanical tests are carried out.The experimental results show that the tensile strength of ECC and MMA materials is larger than that of ordinary concrete.The maximum tensile strain is 200 times and 400 times that of ordinary concrete.Secondly,the finite element model of the spliced box girder bridge is established,and the stress state of the box girder bridge under shrinkage,creep,uneven foundation settlement and live load is analyzed.According to the results of ECC and MMA tensile test,the constitutive relation of the material is established.Analysis of splicing section with ECC and MMA materials,the mosaic box girder bridge force state.This paper analyzes the stress state of the bridge girder bridge when using ECC and MMA materials.The results show that,when the ordinary concrete is used in the splicing section,the tensile strength of the box girder is caused by the uneven settlement of the foundation,which causes the cracking of the concrete.Splicing section with ECC and MMA material,can reduce the splicing box girder flange plate and splicing section of the tensile stress,to avoid cracking of concrete.Then,the key factors influencing the force of splicing bridge are parameterized.The influence of splicing waiting time,foundation settlement difference and splice width variation on bridge structure is analyzed.The results show that the longer the wait time is,the smaller the longitudinal tensile stress caused by the contraction of concrete and the effect of creep.The difference of foundation settlement has great influence on the lateral stress of the flange plate,and the problem of uneven settlement of the foundation should be focused on the bridge splicing Finally,the feasibility of simply connecting T-beam deck is analyzed based on the continuous renovation project of T-beam deck of Nanjing Yangtze River Bridge.T beam was originally used rock bearing,after the calculation of the bridge deck after the active bearing tilt angle is too large,fixed bearing shear force is too large and the pier bottom of the tensile stress than the tensile strength of concrete.Combined with the T-beam deck continuous characteristics,consider the rock shaft bearing replaced with a plate rubber bearing.In addition,ECC or MMA is used as the deck continuous plate material in order to improve the continuous prevalence of cracking and leakage of water in existing concrete bridges.This provides an alternative to improved ride comfort for simply supported girder bridges with steel supports.