高强钢管-超高性能混凝土拱承载能力研究

Experimental study on bearing capacity of high strength steel tube-ultra high performance concrete arch

随着高强度材料的发展与应用,以及对轻质大跨工程结构的实际需求,高强钢管-超高性能混凝土组合结构应运而生。高强钢管与超高性能混凝土(UHPC)的结合可以大幅度提高实际工程结构的承载能力,同时也可以有效降低结构自重。通过对3组高强钢管-超高性能混凝土拱肋模型进行五点对称竖向加载试验和有限元数值模拟,研究了高强钢管与UHPC组合而成的钢管混凝土拱的承载能力,并与已有研究的高强钢管-高强混凝土拱、高强钢管-普通混凝土拱的承载能力进行了对比分析。结果表明:拱肋模型受轴压为主,试件在达到极限承载力的70%之前处于弹性阶段,当拱肋截面上、下翼缘出现拉、压应变时,该截面会发生较大的塑性变形,其中拱脚处应变值最大;UHCFST拱承载能力随着混凝土强度、钢管强度、含钢率和矢跨比的增加而增加,随着长细比的增加而减小。通过参数分析,提出了UHCFST抛物线拱的承载能力设计式,并通过将计算式计算曲线与有限元计算的稳定系数对比,得到99%有限元计算结果都在所提计算式曲线上方,表明该式可以有效预测UHCFST拱平面内弹塑性承载力,可为实际工程设计提供理论参考。

With the development and application of high strength materials,the combination of ultra-high strength concrete and high strength steel is becoming attractive for long-span engineering structures.The combination of high strength steel tube and ultra-high-performance concrete(UHPC)can not only greatly improve the bearing capacity of practical engineering structures,but also effectively reduce the dead weight of the structures.The bearing capacity of the arch with UHPC-filled high strength steel tube was investigated by experiments and finite element numerical simulation,and compared with that of high strength steel tube-high strength concrete arch and high strength steel tube-normal concrete arch.The model is mainly subjected to compression.The arch rib is in the elastic stage before loading to 0.7F;.When the tensile strain occurs in the cross-section,large plastic deformation occurs,and the largest strain occurs at the arch foot.The results show that the bearing capacity increases with rise-span ratio,strength of concrete and steel tube and steel content ratio,and decreases with slenderness.Through the comprehensive parametric analysis,the bearing capacity design formula of UHCFST parabolic arches was proposed.A great number of finite element results generated by ABAQUS models were compared with the stability coefficient in the code.It can be observed that finite element results agree well with the code curve,which indicates the formula presented in this paper can be used to predict the elastic-plastic bearing capacity for the UHCFST arch.