钢-钢纤维混凝土组合桥面板偏心受拉性能

Eccentric Tensile Behavior of Steel-Steel Fiber Reinforced Concrete Composite Bridge Deck

摘要:

为探究钢?钢纤维混凝土（SFRC）组合桥面板在主梁体系下的偏拉力学特征，分别设计制作了1个普通混凝土组合桥面板和1个SFRC组合桥面板试件进行偏拉试验，并引入材料塑性损伤模型进行有限元模拟，考察了偏拉荷载作用下SFRC对组合桥面板破坏形态、刚度折减、应变分布等力学性能的影响规律。试验及数值分析结果表明，相比普通混凝土，SFRC受拉裂缝数量多但宽度小；通过观测钢筋应变发展及分布可知，由于SFRC具有拉伸硬化特性，在开裂后仍能继续承担外部荷载；SFRC开裂后，其对组合板轴向抗拉刚度与侧向抗弯刚度贡献明显大于普通混凝土；当最大裂缝宽度分别为0.10和0.20 mm时，SFRC对组合板的轴向抗拉刚度贡献为36%和22%，普通混凝土仅为15%和11%；SFRC对组合板的侧向抗弯刚度贡献为41%和27%，普通混凝土仅为29%和17%，表明SFRC开裂后仍可考虑其对组合桥面板刚度贡献。此外，结合理论推导分析了组合板在钢结构全截面屈服时的承载力，结果表明，SFRC和普通混凝土对组合桥面板极限承载力贡献不显著。

Abstract:

In order to investigate the mechanical characteristics of steel-steel fiber reinforced concrete （SFRC） composite deck under eccentric tension load in the main girder system， eccentric tension tests of normal concrete composite bridge deck and SFRC composite bridge deck specimens， together with finite element analyses based on the plastic damage model of materials were executed. The influence of SFRC on failure form， stiffness reduction and strain distribution of composite bridge deck under eccentric tension load were investigated. The test and numerical analysis results showed that， compared with normal concrete， SFRC presented characteristics of more cracks but smaller crack width during the development of tensile cracks. By observing the strain development and distribution of reinforcements， SFRC could continue to bear external load after cracking due to its tensile hardening property. After cracking， the contribution of SFRC to axial tensile stiffness and lateral bending stiffness of composite deck was significantly greater than that of normal concrete. When the maximum crack width was 0.10 mm and 0.20 mm， respectively， the contribution of SFRC to axial tensile stiffness of composite deck was 36% and 22%， while that of normal concrete was only 15% and 11%； the contribution of SFRC to lateral bending stiffness of composite deck was 41% and 27%， while that of normal concrete was only 29% and 17%. In addition， combined with theoretical derivation， the ultimate bearing capacity of composite deck under full section yield of steel was analyzed. The results showed that the contribution of SFRC and normal concrete to ultimate bearing capacity of composite deck was not significant.