钢-高强混凝土组合梁收缩的计算分析

对简支和连续组合梁,按照全截面法基于有效模量比计算收缩徐变所退化的混凝土翼板面积和惯性矩,推导了各种收缩效应的计算公式。对比欧洲混凝土模式规范的新旧模型,结果表明:在简支梁的收缩自应力和挠度上,高强和普通混凝土几乎相同;在连续梁的收缩次弯矩上,高强略小于普通混凝土;按照MC1990收缩徐变模型将显著低估这些收缩效应,由此低估钢筋用量将可能引起混凝土开裂等结构的使用和安全问题。

Calculation and Analysis on Shrinkage of Steel High-strength Concrete Composite Beams

For simply supported and continuous composite beams,the reduced area and inertia moment of concrete slab are calculated based on the the ratio of effective elastic modulus according to the whole section method,the corresponding analytic formulas of shrinkage effects are deduced.Compared the new and old model given by European Concrete Model Code,the results show that the difference between high-strength and ordinary concrete in shrinkage stress and deflection of simply supported beam is small,the result of high-strength concrete is smaller than that of ordinary concrete in secondary moment of continuous beam,and if still according to the MC1990 model these shrinkage effects will be underestimated significantly,which may cause the usage and safety problems of structures,such as concrete cracking caused by underestimating the quantity of reinforcement.