Optimization Design And Reliability Analysis For Reinforced Concrete Frame Structural Member

China’s construction industry is at the construction and reinforcement stage, and transferring forward to the third stage of existing reinforcement and reconstruction. In reinforcement and reconstruction of buildings, concrete frame structure is one of the most widely used structure and the reinforcement design of this kind of structure will account for more and more share. Reinforcement design including the slection of reinforcement schemes and reinforcement parameters design. At present, when selecting the reinforcement scheme, designers emphasize one or several factor mainly according to the practical experience with a strong subjectivity. They are unable to realize comprehensive benefit best. In the reinforcement parameters design, designers often just get components separated, and determine the reinforcement parameter values,and bearing capacity of member according to specification hand count or small computing software, then check the stiffness and stability of components only to prove the feasibility of reinforcement design which can not achieve the minimum cost of the reinforcement. Pay attention to strengthen local members, ignoring the calculation of the whole structure after reinforcement and not taking into account the overall bearing force, it leaves a security risk. At present, domestic reinforcement design method is a kind of limit state design method which based on the approximate probability,researches on reliability degree of reinforcement structure members are few, which makes the coordination reinforcement design and identification with reliability difficult.In order to understand the selection of reinforcement schemes scientifically, this paper presents a reinforcement scheme optimization model based on combination weighting and TOPSIS method. Establish the second level evaluation index system which comprehensively reflects economic rationality, technical feasibility, reliability and the overall efficiency of reinforcement schemes,determine the weight of index portfolio using AHP and entropy method which considers the decision of the subjective intention and the objective reality of structure. Calculate the ideal solution and the negative ideal solution of multiple objective decision with TOPSIS method.Calculate the Euclidean distance and the relative closeness according to far away from the negative ideal solution and by nearly negative ideal solution to evaluate the advantages and disadvantages of each scheme, determine the comprehensive benefits Optimal reinforcement scheme.Aiming at the blindness of determination of the reinforcement parameters during design, this paper establishes four optimization design models of structural constraints which set unit length member reinforcement minimum cost as the goal, set reinforce parameters as variables, considering the component bearing capacity and the normal use the normal use as constraints. Four optimization design models are enlarging section method in strengthening frame beam, bonding steel plate method in reinforcement of the beam, increase section method of RC frame column. Outsourcing steel reinforced concrete frame column.Describes the inner point penalty functions method with which solve the optimization model. Put forward the steps of the reinforcement parameters design considered the whole effect of the structure which is preliminary obtained reinforcement design parameters are substituted into the whole structure, confirm whether generate a new weak parts after stress redistribution, if there is, according to the new control force, reconstitute them into the optimization model for the calculation until achieve the requirements of structure.For the coordination of reliability evaluation and reinforcement design, take axial compression concrete column which reinforced by steel-packing as example, study the reinforced component reliability, put forward the methods to calculate the statistical parameters of resistance after reinforced. Finally, bring in a reinforcement engineering example, apply the theory above to realize reinforcement schemes optimization and reinforcement parameters optimization design, analyse and compare the reliability ofcomponents before and after the reinforcement.Test the feasibility and applicability of the theory, providing a theoretical reference to our country’s following concrete frame reinforcement design.