考虑配钢的混凝土徐变换算弹性模量
Creep-Transformed Elastic Modulus of Concrete Considering Steel
摘要: 为在徐变等效弹性方法中精确考虑时间变化的影响，提出考虑配钢的混凝土徐变换算弹性模量。用徐变换算弹性模量表示等效后的材料特性，用徐变调整系数ψ考虑配钢和荷载递增变化影响，反映了时间变化的徐变影响。考虑滞后弹性应变的修正，基于徐变微分本构推导了ψ的计算公式，影响因子包括徐变系数、加载龄期、计算时间和配钢系数，配钢系数为对称钢筋混凝土与型钢混凝土的统一模式。相比现有弹性模量直接折减一半方法或者有效模量法，考虑了配钢和变量荷载工况，为计算徐变重分布应力补充了一种更为精确的简化计算方法。计算表明：对于轴向徐变，不考虑配钢和荷载的变量工况，结果偏于不安全。为ψ的进一步简化提供了理论依据。
Abstract:
To accurately consider the influence of time variation in the creep equivalent elasticity method, a concrete creep-transformed elastic modulus considering steel reinforcement is proposed. Using creep to convert elastic modulus to represent equivalent material properties, using creep adjustment coefficient ψ considering the influence of steel reinforcement and increasing load changes, it reflects the creep effect of time changes. Considering the correction of the delayed elastic strain, the calculation formula of the ψ is derived based on the creep differential constitutive relation, and the influence factors include the creep coefficient, the loading age, the calculation time and the steel distribution coefficient. The steel distribution coefficient is a unified model of symmetrical reinforced concrete and steel reinforced concrete. Compared to the existing method of directly reducing the elastic modulus by half or the effective modulus method, it considers steel reinforcement and variable load conditions, providing a more accurate simplified calculation method for calculating creep redistribution stress. The calculation shows that for the axial creep, the result is unsafe if the steel and the load increasement are not taken into account. It provides a theoretical basis for further simplification of ψ.
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