Research On The Method Of Transverse Entirety Detection For Fabricated Hollow Slab Beam Bridge

In recent years,with the rapid development of society,the bridge construction of our country has made remarkable achievements.And due to its advantages,such as simple structure form,prefabricated convenient and low cost,fabricated hollow slab beam bridge becomes the most widely used form in the design of our country's small and medium span bridge.But according to the study found that,it's very common phenomenon for the hollow slab bridge in the service stage that the transverse entirety of the structure is destroyed which caused by the hinge joints injury.Therefore,the research on the method of transverse entirety detection for hollow slab beam bridge has important realistic significance and practical value.As the main components of transverse connection,hinge joints play an important role to assure the transverse entirety of the structure.Therefore,the article analyzed the mechanical behavior of the hollow slab bridge and the causes for the common diseases of the hinge joints.The finite element model of the bridge is established by Midas civil to carry out the numerical simulation experiment.Based on these research,this paper put forward a new method of transverse entirety detection.The specific research work are as follows:(1)The lateral integrity of hollow slab bridge is tested by the method of transverse distribution influence line,and is verified by the actual bridge test.By establishing the calculation model of hinge joints in different damage conditions,transverse distribution influence line can be calculated.Compared with the influence line of the joint in the perfect condition,it is found that the cross phenomenon will appear in the area of the damaged joint.Therefore,it can be used to identify the joint damage through the cross phenomenon of the transverse distribution influence line,so as to make an effective evaluation of the lateral integrity.At last,the test results show that the method is effective.(2)The effectiveness of the detection method based on the transverse distribution influence line is discussed through the sensitivity analysis of the index when the jointdamage occurs in different location and degree.And analyzes the impact on the accuracy of the method with the bearing damage.The results show that this method has certain limitations.It can not be accurately identified for the joint damage that appears near the bearing,and the bearing damage also has a certain interference effect on the method.(3)Different from the traditional method,a new method of lateral integrity detection of hollow slab beam bridge based on symmetrical difference influence line is proposed.Based on the theory of influence line,the detection indexes of relative displacement,relative angle and relative strain are established by symmetrical difference method.And according to the characteristics of the symmetric difference influence line,we can achieve to determine the damage of the hinge.(4)Through the comparison of the effectiveness and applicability analysis of the above three detection indexes,it is concluded that all three are effective for the evaluation of the lateral integrity.We can choose the method flexibly according to the different test environment and conditions.(5)The detection method based on the symmetrical difference influence line can get a large amount of information by using a few measuring points,so as to get rid of the dependence on the measuring points.During the application process,the new method has good economy,simple data processing and high stability.Moreover,in the face of the actual bridges with non-homogeneous section or material parameters,the principle of the difference can avoid the problem that the detection result of traditional method is not accurate enough due to the lack of precision of the finite element modeling.The proposed method is of great significance for the future application of the bridge structural health monitoring system.