Study On Equipment-Adjacent Structure-Soil Interaction Based On Real-Time Dynamic Substructure Test

With the rapid development of society and economy and the rapid expansion of population,the construction land in cities is becoming increasingly tense,which promotes the emergence of a large number of high-rise buildings.For the analysis and design of tall building structures(including internal equipment)on soft soil foundation and with small spacing between them,considering the structure-soil interaction only can not fully reflect the actual situation of the project.When earthquake occurs,not only the single building structure will interact with the foundation soil,but also other building structures close to the single building structure will affect it through the foundation soil,that is,adjacent structure-soil interaction(ASSI)or equipment-adjacent structure-soil interaction(EASSI).In view of the complexity and enormity of adjacent structural systems,most researchers have focused on numerical simulation and obtained some valuable conclusions and results,but few achievements have been made in experimental research,which results in the lack of a large number of effective experimental data support.However,considering ASSI(or EASSI)in shaking table test is a difficult problem in structural seismic test.Based on this,the shaking table test method is explored in the article.By fusing substructure test technology and introducing branch modal method for the first time in the test,the numerical calculation of linear foundation model and physical test of upper model structure are connected by using interaction coupling term between multiple substructures,and the real-time dynamic substructure test considering ASSI(EASSI)effect is realized.On this basis,the local nonlinear numerical model of foundation is established by using the constrained modal method of linear and nonlinear coupling,and the domain reduction analysis method is applied to the boundary treatment of the foundation model of adjacent structure system for the first time.The real-time dynamic substructure test method of adjacent structure-nonlinear soil system is explored.Based on the derived substructure motion equation and the advantages of different calculation software,a multi-sub-structure cooperative analysis method is proposed to simulate the test.The method is applied to the study of seismic response law of adjacent structure-soil system and the analysis of influence parameters.The main research work and achievements are summarized as follows:1.The branch mode method is effectively applied to the real-time dynamic substructure test of adjacent structure-soil system and equipment-adjacent structure-soil system for the first time.Based on the branch mode method,the upper structure and foundation soil of the systems are divided into different branches.The concept of interaction coupling term among substructures is proposed and applied to data interaction between physical substructure and numerical substructure.At the same time,the substructures are independently loaded or analyzed and processed easily depending on reliable substructure motion equation.The formula derived from the branch mode method has universal applicability,and the concept of the test method is clear and the operation is convenient and flexible.2.Taking the adjacent structure-soil system composed of two adjacent 1:5 ratio four-storey shear steel frame structures and foundation soil as an example,the real-time dynamic substructure test of adjacent structure-soil system based on the branch mode method is realized by setting one of the structures as physical substructures and the foundation soil and adjacent superstructure as two numerical substructures.By using the branch mode method and truncation criterion of potential energy criterion,it is convenient to compress the DOFs of the numerical substructure of linear foundation soil.At the same time,the closed-loop numerical integration method is introduced into the numerical solution of the substructure model of the non-linear upper adjacent structure,and the fast and efficient calculation of each numerical substructure is realized.Thus the problem of time limitation of numerical substructure computation in experiments can be effectively solved,which will provide guarantee for real-time interaction of substructure data.The applicability and validity of real-time dynamic substructure test based on the branch mode method are verified by comparing the experimental and numerical results.3.On the basis of real-time dynamic substructure test of adjacent structure-soil system,the equipment-main structure is set as a physical substructure,and the numerical substructure remains relatively unchanged.Real-time dynamic substructure test of adjacent structure-soil system considering the influence of non-structural(equipment)factors is realized,that is,equipment-adj ac ent structure-soil interaction.The effects of EASSI effect,the existence of equipment,the mass ratio and frequency ratio of equipment to main structure,and the plane position of equipment in main structure(central and eccentric layout)on the seismic response of EASSI system are emphatically studied,and some valuable conclusions are obtained.4.Based on the research results of real-time dynamic substructure test of adjacent structure-soil system and equipment-adjacent structure-soil system with linear simplified foundation model,the method of nonlinear foundation numerical model participating in real-time dynamic substructure test is explored.By applying the constrained mode method of linear and nonlinear coupling to establish the local nonlinear foundation numerical model,and introducing the domain reduction analysis method into the experiment for the first time to treat the boundary of the foundation model,the computational efficiency problem of the nonlinear foundation model is effectively solved.Comparing with free boundary model and viscoelastic boundary model,the accuracy and effectiveness of local nonlinear foundation model based on domain reduced boundary are verified,and its obvious advantages in computational efficiency are demonstrated.5.Based on the reliable substructure motion equation derived by the branch-constrained mode coupling method,and with the advantage of different computing software,a multi-substructure collaborative analysis method is proposed to simulate the real-time dynamic substructure test of adjacent structure-nonlinear soil system.The feasibility and validity of the nonlinear foundation numerical model in real-time dynamic substructure test are discussed and validated based on this method and a specific example.Here,the upper physical substructure S1 and the adjacent numerical substructure S2 are modeled and solved by Simulink simulation tool.The non-linear foundation model is independently analyzed and calculated by ANSYS,and the substructures are coordinated and interacted by MATLAB numerical calculation platform and the interaction coupling terms.6.The multi-sub structure collaborative analysis method is applied to the seismic analysis of the adjacent structure-soil system composed of two adjacent 16-storey reinforced concrete frame structures and foundation soil.The seismic response law of the system is systematically studied and the influence parameters considering ASSI effect are analyzed.The effects of seismic wave characteristics,traveling wave effects,spacing between two adjacent structures,depth of foundation embedding and floor number of superstructure on the seismic response of superstructure of ASSI system are studied emphatically,which enriches and improves the theory of seismic analysis and design of Engineering structures.