Research On Hinges Joint Damage Identification Of Assembled Hollow Slab Bridges Based On Improved Theory And Information Entropy

In recent years,assembled hollow slab bridges have been widely used in small and medium-sized bridges.As the main transverse connecting member of the bridge,hinge joint of this type of bridge is very prone to damage.How to achieve fast and accurate damage identification and assessment for hinge joint has attracted more and more attention from industry experts.However,due to the structural characteristics of hinge joints,it is difficult for traditional bridge detection methods to accurately identify hinge joint damage.Therefore,it is one of the important research directions in the field of bridge health monitoring to find a more accurate method for identifying joint damage.Based on the previous research content,this paper has carried out the following related researches on the damage recognition method of hinge joint:(1)Introduced and discussed the traditional calculation theory of assembled hollow slab bridge,and pointed out its shortcomings.These shortcomings mainly include:only consider transfer of vertical shear force and not consider deformation of hinge joint.They provide direction for theoretical improvement;In addition,this paper also introduces information entropy theory and generalized local information entropy calculation method and characteristics,which provides a new idea for structural damage identification.(2)Aiming at the shortcomings of traditional theories,this paper considers the hinge joint’s actual force and existing research to consider the hinge joint’s lateral force,vertical shear force and deformation,a hinge joint calculation model based on the spring link system was established.Then,based on this model,a calculation model of assembled hollow slab bridge was established.Finally,based on the model,a calculation method of hinge joint damage factor D is proposed,which is called the improved calculation theory of assembled hollow slab bridge.This method evaluates the overall working performance of hinge joint according to the size of the damage factor D.(3)Establish the numerical model of assembled hollow slab bridge with the help of ANSYS software.The comparison between numerical simulation results and calculation results of improved theory verifies correctness of improved theory.The results show that improved theory is in good agreement with numerical simulation results,and hinge joint damage factor D can locate and quantitatively describe damage of hinge joint;In addition,the accuracy of hinge joint damage factor D is related to loading position.When the loading position is closer to damaged joint,the calculated value of damage factor D is closer to the present value.Finally,this paper studies and verifies the practicability of improved calculation theory through bridge static load tests.Experiments show that this method does not require additional measurement points,and only by combining the calculation results of multiple loading cases,the work performance of the hinge joint can be evaluated.This shows that the improved calculation theory can improve the accuracy of the detection results without increasing the cost of bridge detection,and has certain engineering practicability.(4)In order to identify the local damage of hinge joint,this paper combines the generalized local information entropy and the element strain energy to construct a local damage identification index D_L of hinge joint.It is called a local damage identification index D_L of hinge joint based on local energy information entropy.In order to study the characteristics of the local damage index D_L,ANSYS numerical simulation and index noise analysis are performed in this paper.The results show that the damage index D_L can accurately identify single-point and multi-point local damage of hinge joint,and quantitatively describe the degree of damage;At the same time,the damage index D_L has high damage sensitivity,which can achieve accurate damage location and describe the damage degree for small damage with a damage degree of 10%;In addition,the damage index D_L has high noise resistance,which can ensure the correctness of damage identification under the noise interference with a signal-to-noise ratio of 20d B or more.