Numerical Simulation Of Fire Resistance Of Cross-laminated Timber Components Based On OpenSees

In recent years,with the rapid development of construction industry in China,the architectural structure is becoming more and more diversified.As the National key research and development plan key special projects "Green Building and Building Industrialization" progresses,the research and engineering application of wood structure architecture have been greatly promoted.Modern wooden structures have been widely concerned at home and abroad because of its advantages of environmental protection and energy saving.Meanwhile,a variety of engineered wood products have also been put into practice.Cross-laminated timber（CLT）is one of the modern wood products.Due to the orthogonal laminates,CLT is often used in the construction of floors or walls.However,the fire resistance of wood structure has always been an important factor to delay its development,and the research on the fire resistance of CLT components is not deep enough.In addition,the experimental research related to the fire resistance of CLT components is costly and requires high test equipment,which reduces the research enthusiasm of researchers.Therefore,it is necessary to explore the use of efficient and accurate computer software to simulate and predict the fire resistance of CLT structure buildings.In this dissertation,the CLT wall and CLT floor were taken as the research object,and the finite element analysis software OpenSees was used as a tool to explore the numerical simulation method of fire resistance performance of CLT components.The main content of the study is divided into the following parts:（1）The research status of CLT walls and CLT floors at home and abroad was summarized,including the bending performance,shear performance and fire resistance of CLT floors,and the mechanical properties and fire resistance of CLT walls at room temperature.（2）The material model TimberEC5 for wood heat transfer analysis was developed and added in OpenSees.The accuracy of TimberEC5 material was verified by simulating the temperature field of CLT fire test.The standard fire simulation of wood-based components or structures was realized in OpenSees,and the change of internal temperature field of specimens at different moments was obtained.（3）The material constitutive satisfying wood anisotropy was developed and added in the OpenSees mechanical material library,namely EPTimber,EPTimberThermal,and EPTimberThermal After.They realize the change of mechanical properties of wood at room temperature,high temperature and high temperature,so that the thermal-mechanical coupling numerical simulation analysis of wood structure can be carried out on the OpenSees platform,considering the influence of fire load on structure or component.A simple uniaxial tension and compression test was carried out to verify the effectiveness of the developed materials and the matching with the OpenSees platform.（4）The numerical simulation of the residual bearing capacity test and the fire resistance limit test of the CLT wall after fire was carried out.Through the parametric analysis of the CLT wall,the influence of the height-thickness ratio,the composition of the laminate and the fire time on the fire resistance of the wall was explored,including the residual bearing capacity and the fire resistance limit,and the corresponding variation law was given.（5）The fire resistance limit test of CLT floor was numerically simulated,and the residual bearing capacity of CLT floor after fire was numerically simulated.The variation law of residual bearing capacity of floor after fire was obtained.Through parametric analysis of CLT floor,the influence of span-depth ratio,floor composition,and fire time on fire resistance of floor was explored,and the corresponding variation law was given.