Unsupported Replacement And Reinforcement Of Concrete Shear Wall And Construction Optimization Design

Concrete replacement and reinforcement is a new method for the reinforcement and transformation of reinforced concrete structures,which can fundamentally solve the problem of engineering quality caused by insufficient concrete strength.For high-rise buildings,when the building structure has insufficient concrete strength,reinforcement treatment often requires a lot of support,which will increase the cost and construction time of the project.The unsupported replacement reinforcement technology does not require a lot of support,which is convenient for construction and application.Wide,high economic efficiency.This article takes Luoyang a actual concrete shear wall unsupported replacement and reinforcement project as the research background,introduces and summarizes the design of unsupported replacement and reinforcement scheme,temporary support installation,dismantling and re-pouring process of unqualified concrete,and construction monitoring system in detail.Layout and other key construction techniques.Through the ABAQUS finite element software,the whole process of unsupported replacement and reinforcement construction was successfully simulated.Combined with the measured data of the arranged sensors and the finite element simulation results,the beams,floor slabs and The stress variation law of the upper wall corresponding to the replacement wall.The influence range of the stress redistribution caused by the demolition process of the wall section during the replacement construction period is discussed.The influence of the stress concentration caused by the opening of the wall section on the reinforcement effect is analyzed,and the normal section of the shear wall before and after the replacement reinforcement is analyzed.Carrying capacity analyzes the security of the reinforced shear wall.Through monitoring data,it is found that the shear wall structure reinforced by unsupported replacement has a stress lag phenomenon,which will affect the effect of replacement reinforcement.For the unsupported replacement and reinforcement project of concrete,the specification has not yet made clear provisions,and existing research has also Pay less attention to the stress lag phenomenon caused by the stress redistribution process caused by the unsupported replacement reinforcement process.In order to make the unsupported placement reinforcement program universal and reduce the impact of the stress lag on the replacement effect,finally for different axial compression ratios,give A general replacement construction plan was proposed.The main conclusions are as follows:(1)After using PKPM to check the cracks and disturbances of the preliminary design of the unsupported replacement reinforcement plan,re-optimizing the construction plan according to the calculation results can meet the requirements of the unsupported replacement reinforcement plan design stage,and the PKPM calculation results can also guide Design of monitoring plan.(2)Using the ABAQUS finite element software,using the life-death element method、equivalent heating method and adding field variables,the time-varying structural and material time-varying effects of the shear wall in the construction phase of unsupported replacement reinforcement were achieved,and the simulation program was verified by comparison with the monitoring data.accuracy.(3)Through the analysis of monitoring data and finite element simulation results,it can be seen that when the shear wall is dismantled,obvious stress concentration will occur around the opening of the demolition.When the construction is completed,the stress concentration will be significantly slowed down due to stress transfer.Beams and slabs connected to the replacement shear wall and a layer of shear wall on the replacement wall will increase the stress due to the stress redistribution caused by the removal and re-casting of the wall segment,but the stress increase is limited and will not cause beams,Destruction of boards and walls.The shear wall after the completion of the reinforcement will have obvious stress lag due to the difference in the removal time of the wall section,which should be considered in the design of the unsupported replacement scheme.(4)In order to reduce the impact of stress lag on the reinforcement effect and make the unsupported replacement reinforcement scheme more general,the construction simulation of different construction schemes is carried out through the ABAQUS software,and finally for different axial compression ratios and different shear wall lengths.Suggestions are given to guide the construction sequence of unsupported replacement and reinforcement,the replacement length of wall sections and replacement materials.