Timing Analysis Of Long-span Large-span Prestressed Beams To Jack Beam And Removing Column With Frame Structures

With the development of society,there are more and more reinforcement and reconstruction projects.Among them,the expansion and expansion of the jack beam and removing column are of great use value in the reinforcement and reconstruction projects.The practice and research of a large number of engineers and technicians in the project Therefore,the pillar extraction technology has a wide range of research prospects.As a technical transformation method for increasing the column spacing,the jack beam and removing column technology is an important part of the modern framework structure reconstruction.However,due to the complexity of the transformation environment,the security risk is high.Therefore,before the construction,the numerical simulation of the pillar pulling process of the frame structure joists can provide guarantees for optimizing the construction process,clarifying the key construction points,and controlling the construction risk parameters.This research based on a scaffolding column pulling project of a commercial structure in SHENZHEN,using finite element software to perform a numerical simulation of the column extraction process for comparation and selection of column extraction underpinning technology;Meanwhile,detailed introduces the key technologies and performance measurement of column extraction transformation.By monitoring of the entire process of pulling out the frames of each frame,parameters like strain,deflection,etc.of the structural components were obtained.The main contents of the current thesis are as follow:The commercial finite element software MSC.MARC was used to numerically model the whole process of jack beam and removing column,and through comparative analysis of the active underpinning and passive underpinning schemes,it was found that under the active underpinning and passive underpinning conditions,The bearing capacity and deformation of the prestressed beam frame structure can be maintained within the safety range,and parameters such as internal force and overall deformation of the structural element can be accurately extracted to provide guarantees for optimizing the construction process,clarifying the key construction points,and controlling the construction risk parameters.Studied the key construction technologies such as foundation reinforcement,beam-column reinforcement,support system design,and pre-stress construction in the transformation of the jack beam and removing column,and tested the performance of the Bayer frame through the static load test,and tested the Bereille beam in the loading process.The structural members are always operating within the elastic range,and the measured values are close to the theoretical calculations.In the tension test of single-ply prestressed beams,the stress change curves of the prestressed beams,newly added columns and to-be-pulled columns during the tensioning process are obtained.In the prestressed tensioning process,the prestressed transfer beams begin to play their roles.As the prestress increases,the load is continuously reduced.The load on the upper part of the structure is transmitted to the new column through the prestressed transfer beam.The new column already bears part of the load,and the structural members of the tensioning process work in the elastic range with good performance.Through the monitoring of the entire process of pulling out the frames of each frame,the data of structural strain and deflection under different prestressed beam frames are obtained.The prestressed beam and the newly added column have good cooperative performance,and the prestressed transfer beam is slow with the process of column extraction.Under the force,the upper load is transmitted to the new column through shear,and the structural members of the column are all working within the elastic range.No cracks or other abnormalities are found.Finally,the measured values and theoretical values are compared,and the resulting strain curves and experiments are simulated.The results are in good agreement.