桥梁负弯矩区钢筋-UHPC锚固行为模拟分析  

Simulation Analysis of Reinforcement-UHPC Anchorage Behavior in the Negative Moment Zone of Bridges

作　　者：曹晓波 CAO Xiaobo(China Railway 15th Bureau Group Co.Ltd.,Shanghai 200000,China)

机构地区：[1]中铁十五局集团有限公司,上海200000

出　　处：《铁道建筑技术》2025年第4期54-56,113,共4页Railway Construction Technology

基　　金：上海市“科技创新行动计划”启明星项目(扬帆专项)(23YF1459900);中铁十五局集团有限公司科技研发计划项目(2023A2,2023B11)。

摘　　要：超高性能混凝土(UHPC)是一种新型纤维增强水泥基复合材料,具备优异的韧性和耐久性。研究UHPC与钢筋之间的锚固行为,特别关注组合梁负弯矩区混凝土开裂问题。通过有限元分析,探讨湿接缝薄覆层UHPC与钢筋的锚固设计及其在荷载作用下的裂缝发展规律。结果表明,UHPC的高致密性可显著提高结构耐久性,其与钢筋之间的锚固机制包括机械咬合、化学胶着和摩擦力;化学粘结对钢筋与UHPC锚固性能作用很小,小荷载作用下即可完全失效;导致UHPC破坏的关键因素是其沿钢筋纵向的开裂,而钢筋锚固作用最终失效的表现为UHPC出现纵向贯穿裂缝;UHPC保护层厚度对锚固破坏模式的影响巨大。Ultra-High Performance Concrete(UHPC)is a novel fiber-reinforced cement-based composite material with excellent toughness and durability.This study investigates the anchorage behavior between UHPC and reinforcing bar,with a particular focus on the cracking issues in the negative moment region of composite beams.Finite element analysis is employed to explore the anchorage design of the wet joint thin overlay UHPC and its crack propagation under load.The results indicate that the high density of UHPC significantly enhances structural durability,and the anchorage mechanism between UHPC and reinforcing bar includes mechanical interlocking,chemical adhesion,and friction.Chemical bonding has little effect on the anchoring performance between steel bars and UHPC,and can completely fail under small loads.The key factor leading to the failure of UHPC is its cracking along the longitudinal direction of the steel bars,and the ultimate failure of the anchoring effect of the reinforcing bars is the appearance of longitudinal through cracks in UHPC.The thickness of UHPC protective layer has a significant impact on the anchoring failure mode.

关 键 词：UHPC 湿接缝 锚固 开裂 数值分析 

分 类 号：U448.216[建筑科学—桥梁与隧道工程]