ECC/钢筋混凝土叠合梁正截面受弯承载力试验与理论研究
Experimental analysis and calculation theory onnormal section flexural capacity of ECC/steel reinfoced concrete composite beams

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。
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. Plane-section 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 ECC's 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.