Section Sizes And Steel Bar Arrangements Optimization For Reinforced Concrete Frame Structure

Reinforced concrete frame structure is one of commonly-used structural forms in industrial and civil architectures.Optimization design of reinforced concrete frame structure can effectively reduce the project cost and is consequently valuable for practical use.In this study,by taking the total material cost as the object function and the strength,height of compressive zone as the constraints,the optimization methods for reinforced concrete frame structures are investigated.The main research work includes the following points:A method is proposed for optimization of frame members,such as beams and columns,and the whole frame structures.The optimization is carried out by adjusting the cross-sectional sizes and the arrangements of steel bars.The optimization of the steel bar arrangements includes the sizes of steel bars,and for bend-up bars,the bending position as well.Some examples,including beams and column members,were investigated to demonstrate the reliability and applicability of the proposed method.Optimization method for prestressed reinforced concrete structures is studied.Based on the detailed analysis of the mechanical behavior of the prestressed beam(with single-sided prestressed bars or both-sided prestressed bars),a computer program is developed,through which the optimization can be conducted.The optimal results for prestressed and common reinforced concrete structural members are compared to show the importance of optimization for prestressed members.In the existing lateral-drift constrained optimization for tall buildings,the contribution of steel bars to the stiffness of beams or columns is usually ignored.To cope with this problem,a method is proposed to consider such contribution.Through analyzing the tension stiffness,flexural stiffness,shear stiffness and torque stiffness,amplifier coefficients for these stiffness are formulated to represent the contribution of the steel bars to the stiffness.A 24-floor tall building,which is supposed to be acted by wind loads,is given as an example to show the effectiveness of the proposed method.