轻骨料混凝土预制预应力空心板受力性能试验与分析

Experiment and analysis on mechanical behavior of lightweight aggregate concrete precast prestressed hollow-core slab

通过对相同配筋率、相同张拉控制应力、相同混凝土强度等级、不同粗骨料混凝土品种、不同跨度的4组8块预制预应力空心板进行三分点受弯试验,研究了配置螺旋肋消除应力钢丝的轻骨料混凝土预制预应力空心板的正截面受力性能和破坏特征。试验结果表明:轻骨料混凝土预制预应力空心板在受弯过程中,经历弹性、弹塑性、塑性三个发展阶段,正截面符合平截面假定;轻骨料混凝土预制预应力空心板具有同普通混凝土预制预应力空心板相似的承载能力和破坏特征;轻骨料混凝土预制预应力空心板的极限承载力可参照现行规范进行计算;依据混凝土规范推荐的截面塑性抵抗矩影响系数γ值来进行开裂弯矩计算具有更大的安全储备;轻骨料混凝土预制预应力空心板的挠度变化满足混凝土规范设计使用要求。

The mechanical properties and failure characteristics of normal sections of lightweight aggregate concrete precast prestressed hollow-core slabs which combined with spiral-rid eliminating stress steel wire were studied by three-point bending tests of four groups of eight precast prestressed hollow-core slabs with same reinforcement ratio, same tension control stress, same strength grade of concrete, different coarse aggregate concrete types and different spans. The test results indicate that lightweight aggregate concrete precast prestressed hollow-core slabs experience three development stages of elastic, elastic-plastic and plastic stages in the process of bending tests, and the normal section objects to the assumption of plane section. The bearing capacity and failure characteristics of the lightweight aggregate concrete precast prestressed hollow-core slabs are similar to those of normal concrete precast prestressed hollow-core slabs. The ultimate bearing capacity of the lightweight aggregate concrete precast prestressed hollow-core slabs can be calculated according to the current specifications. The cracking moment calculated according to the value of section plastic resistance moment coefficient of T recommended by concrete specifications has greater security reserve. The deflection change of lightweight aggregate concrete precast prestressed hollow-core slabs meets the design requirements of concrete specifications.