A Novel Reduced Model Based Structural Damage Detection Method For Frame Building Structures

As the failure and collapse of buildings triggered by accumulated structural damage, earthquake and other natural disasters are great hazards to people’s lives and property, it is of great significance to research on the damage identification method of frame structure, carry out effective safety inspection of structures and identify the damage state of the frame structure so as to prevent the accidents of structural disasters. The carries out research on the simplified model of frame structure with the rotation response of the structure being taken into consideration. On such basis, the parameter identification method and damage identification method for the substructure are studied.The main research content of the paper includes:In chapter 2, based on the equivalent principle of interstory shear force, The paper proposes a simplified model of the frame structure and researches on the model error of it. with the introduction of structure nodes average rotation response, The influence of beam-column node rotation to interstory shear is evaluated. The dynamic response in the horizontal direction of the structure is adopted to estimate the rotation response of the simplified model. The index of relative root mean square error of interlayer shear force is adopted to evaluate the model error between computational structure model and real structure model. Finally, the verification for numerical simulation is carried out for plane frame structure with two layers and eight spans. The results show that the new simplified calculation model is able to reflect the physical parameters and dynamic response of frame structure in a better way compared to the shear calculation model.In chapter 3, the identification method substructure parameter based on the new simplified model is researched. The Fourier transform of structural response is made in the situations in which the structural stiffness matrix is known or not. The least square method is adopted to construct the optimization equation so as to establish the iteration method layer by layer which is used to identify the substructure parameters of simplified model. Then, it makes research on the parameter identification error of the substructure with the appropriate reference response being selected and the CPSD method being adopted to further enhance the accuracy of identification of substructure parameters. Finally, the numerical simulation verification for plane frame structure of eight layer and fifteen layer is carried out. The results show that this substructure method is able to identify the physical parameters of frame structure quite accurately.In chapter 4, identification method of substructure damage based on new simplified calculation model is carried out. Then the SAP2000 program is adopted to establish finite element model of frame structure. Two kinds of damage conditions of simulation frame structure are simulated by changing the size of column section and the consolidation coefficient of beam column joints. The analysis results of one-time history analysis of three structural models show that the method of substructure is able to identify the damage of the structure with the decrease of simplified model substructure layer stiffness and there is certain error existing in the damage severity identified. The analysis results of multiple time history carried out by adopting statistical hypothesis test method show that: the method of substructure is able to identify the damage state of the column with decreased stiffness and the plastic hinge on the column top accurately.