Research And Application Of Enlarged Section Adding Prestress Technology In The Demolishing Column Engineering

Demolishing column is a rapidly developed underpinning reconstruction measure,and it meet the new using requirements of the existing buildings. And enlarged section adding prestress technology combines the increasing the sectional method and prestressed strengthening method,so it is widely used in the demolishing column underpinning reformation. The strengthening method can full exert the advantage of increasing the sectional law and increasing the law of prestressing force below the premise that follows the principle of frist reinforcement before reformation.Then it obtained the good result in many fact projects. Thus, the experiments on the enlarged section adding prestress technology are very important no matter in design or in construction.In this paper, all factors taken into consideration and two beams are designed to reinforce by enlarged section adding prestress technology, then demolish column test and drab static loading test are conducted after reinforcement. The phenomenon and result of the test are processed and analysed. Result shows that after reasonable design the method can exert positive influence in operation; in addition, by the drab static loading test analysis, we found that part of the current prestressed concrete theory can be used to design. The above test results can provide certain referenced value for engineering practices in future.In this paper, using SAP2000 to conduct static analysis for a demolish column reconstruction engineering, fristly, we build solid models before and after strengthening for different working conditions, then calculation and analysis are carried out, after column demolishing internal force are almost intact using enlarged section adding prestress technology and don’t have any harmful effect on the whole structure.At the same time, the technique can effectively control bending members’ vertical deformation, so, the members’ bearing capacity need not be significantly increased and the vertical deformation is effectively controlled in the place where the column demolished, then, it give some reference to the actual project.Based on the experimental studies,we summarize the technology, draws out some conclusions and put forward some proposals to future engineering practice. In addition, we point out many shortages and some works needing to be improved though experiment.