Study On Line Damageidentification Consideringtransverse Distribution Of Load

The local damage of the bridge will not cause immediate damage to the whole structure,but it poses a potential threat to the safety of the whole structure.Timely detection of early damage and maintenance,can reduce the maximum maintenance costs and the occurrence of bridge accidents.At present,all countries are faced with the peak of bridge maintenance.On the beam bridge damage identification research,has important theoretical significance and practical value.At present,the study on Damage Detection Based on deflection of the line is based on single beam and multi beam bridge is actually the spatial structure.There are interaction between each longitudinal beam,the need to consider the influence of transverse connection bridge.In this paper,the main problems of the current damage identification,especially the main problems of the damage identification method of the line damage identification method are studied.? The significance of bridge structure damage identification and the main methods of bridge structure damage identification are summarized.The problems and shortcomings of these methods are analyzed.In particular,the identification method of line damage for influence of deflection is expounded,and the necessity of considering the interaction between the stringers is clarified.?Simple introduced the basic theory of grillage method and beam slab bridge of the upper structure,and then using the grillage method built a transverse by six pieces of T beam simply supported girder bridge with rigid connection.And the transverse connection mode of the model was verified by simulation test and look-up table method.Finally,the sensitivity factors affecting the mid-span deflection value of the model were analyzed and compared.?Based on the theory of lateral load distribution,the analytical solution of the second-order derivative of the mid-span deflection difference line and the mid-span deflection difference considering the transverse load distribution of the load is derived,and the following conclusions are obtained.Then,through the numerical simulation,the single and multiple damage of the simply supported girder bridge are identified,and it is found that the second derivative of the mid-span deflection difference is better than that of the mid-span deflection difference line Damage identification.?Based on the lateral load distribution theory,the analytical solution of the two-order derivative of the difference of the deflection difference between the line and the middle span is derived.The quadratic relationship between the symmetrical load and the moving load position is obtained.Then,the numerical analysis of the single and multiple damage of the simply supported girder bridge is carried out.It is found that the second-order derivative of the mid-span deflection of the simply supported T-beam bridge can be well damaged without the original structural information.?Based on the analysis of symmetrical loading theory,the damage of bridges is studied by changing the nature of the bridge,considering the interaction between the stringers,changing the number of the bridge,changing the number of the longitudinal girder,the oblique angle and the bridge.It is found that the second derivative of the mid-span deflection based on symmetrical loading is suitable for the damage identification of simply supported T-beam bridges and continuous girder bridges with cross-bridge hinges,varying number of main girders and oblique angles.