UHPC在槽形钢-混凝土组合梁的应用与分析

摘要:

超高性能混凝土(UHPC)与普通混凝土相比,结构自重轻,抗弯折强度大、耐久性能好,其与槽形钢梁组合形成的钢-UHPC组合梁更具应用前景。本文以某大跨连续钢-混组合梁为工程背景,对钢-UHPC组合梁和钢-C50组合梁进行整体和局部对比分析。结果表明,整体计算中,钢-UHPC组合梁的刚度略小于钢-C50组合梁,基本组合下钢-UHPC组合梁中钢梁应力比钢-C50组合梁下降约27%。局部有限元分析中,频遇组合下钢-C50组合梁的桥面板已开裂；钢-UHPC组合梁桥面板的最大拉应力作用范围比钢-C50组合梁小,仅出现在纵肋下缘,且最大拉应力小于UHPC材料的开裂应力。钢-UHPC组合梁大幅降低结构自重,可进一步减小钢梁截面,有望解决大跨度连续组合梁中桥面板开裂问题。

Abstract:

Compared with ordinary concrete, Ultra-high performance Concrete (UHPC) has lighter weight, higher bending strength and better durability. The steel-UHPC composite beam formed by UHPC combined with channel steel has more prospects for applying. Based on the background of a long-span continuous steel-concrete composite beam, the overall and local comparative analysis of steel-UHPC composite beam and steel-C50 composite beam is carried out in this paper. The results show that the stiffness of the steel-UHPC composite beam is slightly smaller than that of the steel-C50 composite beam, and the stress of the steel in steel-UHPC composite beam is about 27% lower than that of the steel-C50 composite beam in fundamental combination. In the local finite element analysis, the deck of steel-C50 composite beam has cracked under frequent combination, the maximum deck stress of steel-UHPC composite beam is less than the cracking stress of UHPC material, which only appears at the bottom of longitudinal ribs, so the deck will not crack. The steel-UHPC composite beams can greatly reduce the dead weight of bridge and further reduce the section of the steel beam, which is expected to solve the problem of bridge deck cracking in the long-span continuous composite beam.