Theoretical Research On The Load Capacity Of Eccentric Compressive Circular Section Column By Enclosed Reinforcement

With the economic development and social progress,it is necessary to reinforce the old bridge because of the time and the traffic increse.Nowadays,the reasearch on the pier and column is mainly about the study of axial compression reinforcement,but the reaserch on the the eccentric compression column is little ,so it is necessary to do some reaserach on the eccentric compression column. Enclosed reinforcement method is a widely used and relatively cost-effective method to reinforce. The reinforcement on the pier and column is a two-phase composite structure of the force,including before and after the reinforcement.The paper derives surround sheath eccentric compression circular reinforcement bearing capacity formula through reasonable assumptions and the basis of theoretical analysis, the analysis of the reinforcement column's bearing force characteristics and damage characteristic and the analysis of their ultimate state . Then we will use the formula to calculate the example's bearing capacity.At last in order to verify the rationality and correctness of the theory formula, the paper uses the ANSYS finite element simulation software to simulate and analyse the force characteristics of the column.Then the paper compares the two results from the formula and the software, the two results tally each other.We can get the conclusion that : this formula that the paper deduces is reasonable. This paper is divided into five chapters, Chapter II, III and IV are the core parts of this paper. The first chapter introduces the status quo of the reinforcement theory at home and abroad and shows the shortage.Then it shows the significance of this paper and at last the chapter gives the main content ot this paper.The second chapter is one of the core parts.It supplies the basic theory for deducing the formula in the third chaper .The theory considers such factors: the Poisson's ratio, the constraint of the surround sheath ,the impact of the improving coefficient of the stirrup on core concrete strength . At the same time ,it deduces a mehtod to calculate the improving coefficient of the core concrete strength .It confirms the scope of the compressive strength reduced of the surround sheath concrete through the analysis of pull and pressure composite stress of the concrete .From the method which calcluates the eccentricity distance increasing factor in China's existing guild regulations we can find out that the impact of reinforcement ratio in the formula is not considered. According to the literature information ,the paper confirms a way to calcluates the eccentricity distance increasing factor considering the reinforcement ratio .Above all,the chapter quotes some reasonable assumptions and other basic theories.The third chapter is the core part of this paper.It confirms its capacity limit state through the analysis of forec characteristics and damage characteristics on the reinforcement column.It deduces a theoretical formula to calculate the bearing capacity of surround sheath eccentric compression circular section in the limit state according the theory in the second chapter.At the same time ,the chapter offer a a relatively simple and straightforward method to determine the size of the eccentric .At last it gives an effective way to calculate the load capacity of surround sheath eccentric compression circular section .The fourth chapter is also one of the focuses of this paper.It uses the formula to calculate the example's bearing capacity.At last in order to verify the rationality and correctness of the theory formula, the paper uses the ANSYS finite element simulation software to simulate and analyse the force characteristics of the column.Then the paper compares the two results from the formula and the software, the two results tally each other.We can get the conclusion that : this formula that the paper deduces is reasonable. This is a good reference information for our design.The fifth chapter is the last part of this paper.Its main content is the summary of the full text and directs the reasearch content and direction in the next step.