采用混杂纤维ECC的叠合板组合梁负弯矩受力性能试验研究

Experimental research on mechanical behavior of composite beams with precast slabs and hybrid fiber ECC under negative momen

基于一种新型混杂纤维ECC材料研发一种钢-混凝土-ECC组合桥面结构,用于连续组合桥梁的负弯矩区以提升其抗裂性能,可代替其他复杂的工程措施。完成2根钢-混凝土-ECC叠合板组合梁和1根钢-混凝土叠合板组合梁的静力单调加载试验。通过对承载力、刚度与裂缝发展的分析,初步论证混杂纤维ECC用于钢-混凝土组合梁的可行性和优势。试验表明:在纵向受拉钢筋配筋率相等的情况下,采用ECC后浇层的叠合板组合梁在正常使用阶段的承载力略高于对比梁,刚度则高于对比梁且裂缝数量减少、宽度减小;在采用界面拉毛处理后,后浇ECC与混凝土之间的黏结性能良好,界面未出现滑移破坏。基于试验数据和规范方法,提出了含ECC构件的受弯裂缝宽度计算公式,公式计算值与相关试验吻合较好。

A new type of steel-concrete-ECC composite bridge structure is proposed with a hybrid fiber ECC material.The new structure can replace other complicated construction measures in the steel-concrete continuous composite beams under negative moment to improve cracking resistance.Experiments were conducted on 2 steel-concrete-ECC composite beams with precast slabs and 1 steel-concrete composite beam with precast slabs under static monotonic loading.The discussion of bending resistance capacity,flexural rigidity and cracking properties demonstrates the feasibility and advantages of hybrid fiber ECC applied to steel-concrete composite beams.The research results show that the bending resistance capacity and flexural rigidity of steel-concrete-ECC composite beam are higher than that of steel-concrete beam when the reinforcement ratio is same.Compared with the steel-concrete beam,steel-concrete-ECC beam can better control the number of cracks and the crack width.The napping treatment is applied to the interface between concrete and ECC,and the mechanical behavior of the interface is good with no slippage damage.Based on the experimental data and formula from codes,the model for calculating the crack width is put forward.The calculation results from the proposed model are in good agreement with test data.