钢筋混凝土构件等效抗弯刚度与结构线弹性设计方法研究OA

Cracking of reinforced concrete(RC)members under loading,as well as concrete shrinkage and creep,affects their flexural stiffness.However,these factors are not considered in conventional linear elastic design for RC structures,resulting in problems such as unreasonable internal force distribution among members,inaccurate bearing capacity calculation,and deviations in overall structural indices,thereby affecting structural safety.To address these issues,a method for calculating the equivalent flexural stiffness of RC members in the elastic stage was established through theoretical analysis.The effects of parameters such as cross-sectional dimensions,concrete strength grade,reinforcement ratio,and axial compression ratio on the flexural stiffness of four types of RC members,namely coupling beams,frame beams,frame columns,and shear walls,were analyzed,and the ranges of stiffness reduction coefficients for these members were presented.A linear elastic design method for RC structures based on stiffness reduction was proposed.The method obtains member internal forces through preliminary analysis of the global structural model,followed by reinforcement design and calculation of the equivalent flexural stiffness of members.The calculated stiffness was then reintroduced into the global structural model for multiple iterative corrections until stiffness convergence was achieved,thereby obtaining member stiffness and internal force distributions consistent with the actual force state.The above process was efficiently implemented through a dedicated computational program.A 200-m-high reinforced concrete frame-core tube structure in Shenzhen was taken as an example to analyze the differences between the proposed method and conventional design methods in terms of stiffness calculation,internal force distribution,and design results,thereby verifying the rationality and applicability of the proposed method.