钢筋混凝土梁正截面率相关特性分析

Sectional Rate-dependent Characteristic Analysis of Reinforced Concrete Beam

根据混凝土单轴动力特性试验,对规范给出的混凝土应力—应变关系表达式进行了修正,引入了应变率的影响,并利用修正的表达式对钢筋混凝土梁的开裂弯矩、开裂曲率、极限弯矩和极限曲率进行了数值分析。分析考虑2种情况:①只考虑混凝土的动态特性;②既考虑混凝土的动态特性,也考虑钢筋的动态特性。结果表明,对于适筋梁,混凝土的动态特性对梁的开裂弯矩、开裂曲率、极限弯矩和极限曲率的影响很小,但是钢筋的动态特性的影响比较大;而对于超筋梁,混凝土的动态特性和钢筋的动态特性对梁的开裂弯矩、开裂曲率、极限弯矩和极限曲率都有显著影响。

According to the dynamic experimental results of concrete,stress-strain relationship of concrete given by design code of reinforced concrete was modified to take the effect of strain rate on concrete into account.Then dynamic characteristics of reinforced concrete beam,such as the cracking moment,cracking curvature,ultimate moment and ultimate curvature,were studied using the modified expression.The study included two cases：（1）only dynamic characteristics of concrete were considered;（2）dynamic characteristics of concrete and reinforcement were considered.The results of numerical analysis show that dynamic characteristic of concrete has little effect on the cracking moment,cracking curvature,ultimate moment and ultimate curvature of moderate reinforced beam but dynamic characteristic of reinforcement has considerable effect on them.Nevertheless,the dynamic characteristics of concrete and reinforcement have obvious effect on the cracking moment,cracking curvature,ultimate moment and ultimate curvature of the over reinforced beam.