Study On Model Updating Of Frame Structures Based On Novel Simplified Model

Damage to the building structure caused by extreme loads such as material aging,environmental erosion,long-term load effects,and earthquakes poses a great potential threat to people's lives and property.In order to understand the safety of the real service structure,scholars from all over the world have carried out research on damage identification and model updating of building structures,and tried to establish a model that can reflect the mechanical behavior of real structures.In order to facilitate analysis and calculation,they often use simple models such as shear models to simulate complex high-rise frame structures.However,since the simple calculation model does not consider the existence of a large number of structural node rotational degrees of freedom,it will inevitably increase the model error of the computational model,which makes it difficult for the modified model to reflect the dynamic response of the real structure.Therefore,choosing a computational model with a small model error is an important prerequisite for improving the accuracy of structural damage identification.In this paper,a novel simplified model considering the influence of rotational freedom of structural nodes is studied,and the model is applied to the research of high-rise frame structure model updating method.The contents of this paper are as follows:(1)Chapter 2 studies the model updating of common high-rise frame structures based on novel simplified model.Firstly,a model updating method based on the simplified model and the actual frame structure shear force equivalent is proposed.A novel simplified model of the frame structure based on the above-mentioned interlayer equivalence principle is proposed.The model considers the influence of structural node rotation to the interlayer shear force,therefore,which can significantly reduce the model error compared to the traditional shear structure model.Secondly,using the above-mentioned inter-layer shear equivalent principle,the parameter identification and model updating methods of the novel simplified model of frame structure are studied.Based on this,a simplified calculation model which can predict the horizontal response of the actual frame structure is established.Finally,a numerical simulation study using a planar frame structure and a three-dimensional frame structure shows that the simplified model proposed in this chapter can accurately reflect the inter-layer shear of the real frame structure,and the computational model based on the simplified model can accurately predict the actual response of the frame structure under external loads.(2)For the frame structure installed with the viscous damper,Chapter 3 studies its structural model updating method based on the simplified model.Firstly,aiming at the inter-layer shear force error of the simplified model,the interlaminar shear force error caused by the viscous damper is studied.Based on this,a new simplified model improvement method considering the viscous damper is proposed and studied the identification method and model updating method of new model's parameters.Finally,through a numerical simulation study of a ten-story three-span plane frame structure,it is verified that the novel simplified model established by this method can reflect the physical parameters and dynamic response of the frame structure with viscous damper very realistically.(3)In Chapter 4,it is proposed to verify the validity and accuracy of the proposed frame structure model updating method based on the novel simplified model through a shaking table test of a 16-story frame structure.However,the experimental results show that the simplified model established cannot accurately reflect the dynamic response of the test frame structure.By carefully analyzing the reasons for the failure of the test,it was found that the test structure did not meet the assumption of infinite stiffness in the plane of the frame structure due to the fixed method of structural weight.