钢纤维混凝土组合桥面板钢箱梁抗负弯性能

Negative Bending Behavior of Steel Box Girder with Steel Fiber Reinforced Concrete Composite Deck

摘要:

对1个C50混凝土组合板和1个钢纤维混凝土（SFRC）组合板试件进行偏拉试验和基于材料塑性损伤的有限元模拟，考察了组合板开裂特性与拉伸刚度变化。在此基础上，建立了钢?混凝土连续箱梁负弯矩区节段模型并进行了参数分析，探究了混凝土材料、SFRC板厚、配筋率对主梁力学性能的影响特征。试验与模拟结果表明：SFRC板开裂呈裂缝细密特点；当裂缝宽度达0.10 mm和0.20 mm时，SFRC板对组合板轴拉刚度剩余贡献为44%和23%，C50板剩余贡献为12%和9%，表明裂后SFRC板仍可参与受力。参数分析结果表明：当SFRC板裂缝宽度达0.10 mm时，SFRC板对主梁抗弯刚度的剩余贡献约为C50板的2倍；此状态下80~120 mm厚SFRC板的主梁抗弯刚度相比未开裂状态下降约11%；增大SFRC板配筋率可改善其损伤程度，但对提高主梁抗弯刚度作用较小。

Abstract:

Eccentric tension tests on C50 concrete composite deck and steel fiber reinforced concrete (SFRC） composite deck specimens， together with corresponding finite element simulations based on the plastic damage model of materials were executed to investigate the axial tensile stiffness reduction and cracking characteristics of the composite deck. Furthermore， segment finite element models of continuous steel box girders with SFRC composite deck were established for parameter analysis to explore the effects of concrete material， SFRC slab thickness and reinforcement ratio on mechanical properties of main girders. The test and numerical analysis results show that the SFRC slab appears more cracks but the crack widths are much smaller. When the crack width reaches 0.10 mm and 0.20 mm， respectively， the residual contribution of the SFRC slab to the axial tensile stiffness of the composite deck is 44% and 23%， while that of the C50 slab is only 12% and 9%， indicating that SFRC slab still has a great contribution to the mechanical performance of the composite deck after cracking. The parameter analysis results show that the residual contribution of the SFRC slab to the bending stiffness of main girders is about twice that of the C50 slab at the corresponding load level with the SFRC slab crack width of 0.10 mm. When the crack width of the SFRC slab reaches 0.10 mm， the bending stiffness of main girders with 80~120 mm thick SFRC slab decreases by about 11% compared with the uncracked state. Moreover， increasing the reinforcement ratio of the SFRC slab can improve the damage degree， but it has little effect on improving the bending stiffness of main girders.