Evolution Control Of Steel Corridor Reinforcement Construction Performance After Fire Based On Health Monitoring

Steel structures are widely used in high-rise buildings and large-span structures due to their advantages such as light weight,high strength,and good seismic performance.After being exposed to fire,the mechanical properties of steel structures will rapidly decrease,but if the overall damage is controllable,they can continue to be used after reinforcement.However,research on the reinforcement construction plan,the performance and stress state of the steel structure during the construction process is very limited.Therefore,it is necessary to conduct research on the performance evolution of steel structures during reinforcement construction,and dynamically adjust and control the construction process.This article relies on the engineering example of post fire reinforcement of the steel structure corridor of Dalian Kaixuan International Building,and provides suggestions for controlling performance during construction.After reinforcement,the reinforcement effect is evaluated.Combining finite element simulation and health monitoring data,the evolution process of steel structure performance is digitized and transparent,thus achieving control of the construction process.The main content is as follows:(1)Introduced the theory of construction performance evolution control,summarized the methods and characteristics of construction performance evolution control.(2)The finite element model of the steel structure corridor was established,and the whole process simulation of reinforcement was simulated and analyzed using the birth and death element method.The static performance analysis showed that the performance parameters during the reinforcement process did not exceed the safety range,and the construction scheme was verified to be reasonable and feasible.The construction control suggestions to prevent stress concentration and excessive deformation were given.The first 20 vibration modes,natural frequencies and natural periods of the structure were obtained from the dynamic performance analysis,Determine the weak floors that need to be focused on during construction through time history analysis.(3)Based on the simulation results,a full cycle health monitoring was conducted on the reinforcement process,selecting sensors suitable for this project,determining the placement position and monitoring frequency of measurement points,summarizing the installation and use methods of sensors,and obtaining stress,temperature,and acceleration data during construction.(4)Analyze the collected data to identify the main factors that affect stress changes.Through stress temperature fitting,further explore the degree of influence of temperature on different positions of the corridor.By observing the strain changes during the entire period of reinforcement at the connecting measuring points between the corridor and the building,it can be seen that the building has well taken on the increased load during reinforcement construction.This article introduces the construction techniques for reinforcement and prevention of internal force mutations in this project.Through the acceleration time history curve,it can be seen that the construction process is smooth.Using wavelet transform for time-frequency analysis,the results show that the reinforcement effectively recovers the stiffness loss caused by the fire in the corridor.This study indicates that using finite element simulation and health monitoring can effectively control the evolution of construction performance,and is of great significance for the design of steel structure reinforcement after a fire and ensuring construction safety during the reinforcement stage.