Theoretical Research And Application Of Enlarging Section Method In Reinforcing Axially Loaded RC Columns

With development of the urban construction, reinforce and reconstruct existing buildings is becoming one of new industries in construction engineering. The reinforcements in concrete occupy over 50% of the whole industry. Increasing section method is a kind of economical and effective way which is also used widely. The paper analyzed the normal section bearing capacity of the columns used increasing section method to reinforce in theory and finite element ways. There are theoretical significances and engineering values in the results.There two stages in the force analysis of enclosed concrete to reinforce column, which include before and after the reinforcement. It's not easy to simulate the situation in labs, however, for the development of the computer science and technology, which make it possible to use computer simulation in the test, and is being used more and more widely in nonlinear process problemsThe article focused on the increasing section method which used widely in practical engineering. With consideration that there is no uploading in the actual situation, deduced and simplified the formulas in calculating the normal section bearing capacity of the column used the increasing section method to reinforce. This is formulas considered about both the stress level index and the restriction effects in enclosed concrete to the core, which also verified the calculating methods to the coefficients. In order to prove and verify the formulas, used ANSYS to do the finite element analysis base on the experiment results from related literature. Frictions between the enclosed concrete and the core were thought about during the analysis, and friction elements were set up in the process. Birth-death elements were applied to simulate the secondary loads on the enclosed concrete. The results revealed that the data from the finite element is similar to the ones from the experiment, which indicate that it is proper to use ANSYS in analyzing the normal section bearing capacity of the columns used increasing section method to reinforce.Based on the related theories and results of the finite element, in addition with the practical engineering to prove the reasonable of the increasing section method, which is suitable to be used for its improving in bearing capacity of the columns been reinforced.