| The frame structure isolation and reinforcement is the base isolation layer set at the bottom of the frame structure,thus prolonging the structure cycle and reducing the seismic action of the upper structure,so that the original structure can meet the seismic requirements without reinforcement or a small amount of reinforcement.Compared with the traditional seismic reinforcement technology,the seismic isolation reinforcement has a small impact on the building,mainly concentrating on the first floor of the building,considering the factors of the construction period and the renovation,and so on.The isolation and reinforcement technology has a more prominent advantage.However,the original frame column should be truncated and replaced by the upper load when strengthening,and the isolation support is added at the truncated frame column.The design and construction of the underpinning system will be made.The key and difficult point of the frame structure isolation and reinforcement is that the current frame structure isolation and reinforcement system is all around the column.Even if the load underpinning is completed,the underpinning beam is pulled out of the work and the beam is still fixed in the structure.The construction is not only difficult,but also the size of the newly added beams is generally large,which affects the layout and function of the building.The structure form,working mechanism and construction technology of the circular hoop type underpinning system are given.Therefore,this paper presents a detachable underpinning system for frame structure isolation and reinforcement,the hoop type underpinning system,and the following studies are carried out for the system:1.The structure form,working mechanism and construction technology of the hoop hoop underpinning system are put forward.The system can be divided into three parts: hoop hoop,the original frame column outsourced steel pipe and filled with concrete to form concrete filled steel tube column,column and the connection node of the original structure.2.The stress of the hoop is analyzed and the finite element simulation is carried out.Through the finite element simulation,the stress distribution hypothesis in the theoretical analysis of the hoop is verified.Finally,a practical steel hoop test is used to verify that the theoretical analysis method of the hoop is more reasonable,and the stress distribution law of the hoop is basically consistent with the result of the finite element simulation.At the same time,the theory of the stress distribution of the hoop is basically consistent with that of the finite element simulation.The calculation of the bearing capacity of the hoop is slightly larger than the test results.Therefore,the friction coefficient of the hoop and the column should be 0.2~0.3,and the load safety factor should be 1.2~1.5 when the theoretical calculation is proposed.3.The finite element simulation and test verification are carried out on the concrete filled steel tube columns formed by the original frame column and filled with concrete.The load deformation relationship of the reinforced concrete frame column is analyzed,and the effect of two factors on the bearing capacity of the reinforced frame column after the reinforcement of the original reinforced concrete frame column and the rare earthquake effect is considered.The effect of the original frame column reinforcement on the bearing capacity of the reinforced column is limited.The effect of the eccentricity on the bearing capacity of the reinforced specimens is remarkable under the rare earthquake effect.Therefore,the design and calculation method of the reinforced column for the steel pipe is given by using the design method of the concrete filled steel tube column.4.The design and construction requirements of the joint joint of the reinforcement column of the outsourced steel pipe and the original frame beam and the foundation are given.The installation method and the construction technology of the isolation bearing in the reinforcement project are given. |
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