高淑玲　郭亚栋　吴耀泉

摘要：

为了探究ECC/高强钢筋混凝土叠合梁的正截面受弯特征，以及ECC层厚度对叠合梁整体受弯性能的影响，做了两组共5根梁试件的正截面受弯试验。发现与高强钢筋混凝土梁相比，叠合梁的承载力更高，相同荷载下的挠度值和最大裂缝宽度较小。在受弯全过程中其截面应变仍符合平截面假定，钢筋与ECC也可以实现协调变形，说明受拉区使用ECC可以使得高强钢筋的应力得到充分发挥。但ECC层厚度过大可能会使叠合梁发生脆性破坏。进一步地，在此研究的基础上，对已有ECC的本构模型进行简化，忽略其应力强化贡献，并运用叠加原理，提出一种用于计算ECC/钢筋混凝土叠合梁正截面受弯承载力的方法，将计算结果与试验结果及诸多文献结果进行比较，发现吻合度较高。

关键词：

叠合梁；正截面；受弯承载力；控裂能力；叠加原理

中图分类号：TU375.1

文献标志码：A文章编号：16744764（2017）02012309

Abstract：

Experiments on normal section flexural capacity with two groups of five ECC/ high strength reinforced concrete composite beams were implemented to explore its flexural characters with different ECC depths. It was found that comparied with steel reinforced beams， composite beams gained more flexural capacity， and had the less deformation and crack width under the same load. Planesection assumption was still applicable ，strains between steel and ECC were also well accorded with，which showed that ECC could bring the high strength steel into full play， while it would happen brittle fracture when the ECCs depth increased to one half of the beam. On the basis above， combined with superposition principle， constitutive model of ECC was been simplified to neglect its stress hardening behavior， a new calculation method for the capacity of the composite beams was proposed. To verify the theory， results by the calculated and the experimented had been comparied.

Keywords：

compositebeams；normal section； flexural capacity；crackcontrol；superposition principle

對于HRB500级钢筋混凝土受弯构件，由于高强钢筋在使用荷载下较大的工作应力和引起的较大裂缝宽度也使构件的变形增大，因此，HRB500级钢筋在普通钢筋混凝土中的高强度发挥受到正常使用极限状态下裂缝和挠度变形的限制，影响了HRB500级钢筋在建筑工程中的大量推广应用。因此，如何有效地控制HRB500级钢筋混凝土的裂缝宽度使其应力得到充分发挥是其推广应用急需解决的关键问题。

工程用水泥基复合材料（Engineered Cementitious Composites，以下简称ECC），是一种基于微观力学和材料力学设计的，以水泥、粉煤灰等粒径不大于5 mm的细集料作为基体，在纤维体积掺量约为2%的情况下就可以获得3%极限拉应变的新型水泥基复合材料[1]。……