免拆模混凝土梁受弯性能试验

摘要

In order to study the bending performance of concrete beam without demoulding,a concrete beam without demoulding and a cast-in-place contrast beam were designed. Two specimens were subjected to unidirectional static loading, and the failure modes, load characteristic values,load-strain curves of concrete,load-strain curves of reinforcement and load-displacement curves of midspan were obtained and compared.The results show that the crack development of concrete beam without demoulding and cast-in-place beam is quite different in the pre-yield phase of component,but the overall damage characteristics of the tw o specimens are basically similar in the end of the failure.The U-shaped concrete formwork of concrete beams without demoulding works well with internal post pouring concrete,and through the entire loading process,the U-shaped concrete formwork doesn't fall off and tear.The cracking load of concrete beam without demoulding is about 8% lower than that of the cast-in-place beam,but the ultimate load of the two specimens are roughly the same.In practical engineering project,the current Code f or Design o f Concrete Structures can be used to calculate the cracking load and the ultimate load of concrete beam without demoulding,and the result is safe.%为研究免拆模混凝土梁的受弯性能,设计制作1根免拆模混凝土梁和1根现浇对比梁,对2个试件进行单向静力加载,得到了各试件的破坏形态、荷载特征值、荷载-混凝土应变曲线、荷载-钢筋应变曲线、荷载-跨中位移曲线,并将其进行对比分析.结果表明:在试件屈服前,免拆模混凝土梁与现浇梁的裂缝发展有较大区别,但最终破坏时2个试件的整体破坏特征基本相似;免拆模混凝土梁的预制U形混凝土模块与内部后浇混凝土结合较好,整个加载过程未出现U形模块脱落或撕裂现象;免拆模混凝土梁的开裂荷载相比现浇梁试件要小8%,但2个试件的极限荷载基本相同,实际工程中可采用现行《混凝土结构设计规范》对免拆模混凝土梁的开裂荷载、极限荷载进行计算,结果偏安全.