摘要
超高性能混凝土(UHPC)是一种具有高强度、高延性、高耐久性的水泥基复合材料,目前被广泛用于预制结构钢筋搭接连接湿接头,早龄期UHPC中钢筋的有效粘结锚固是快速拼装建造的重要保障。本文对处于3天龄期的UHPC中的钢筋进行了拉拔试验,考虑了钢筋锚固长度对粘结锚固行为的影响。结果表明:①试验出现两种破坏模式,分别是钢筋拔出破坏但钢筋未屈服和钢筋拔出破坏且屈服;②对于3天早龄期后浇UHPC接头中的钢筋锚固设计,建议保护层厚度大于2.5倍钢筋直径;③对于3天龄期UHPC中的HRB400钢筋,临界屈服锚固长度为6倍钢筋直径,相比于普通混凝土有效减小了锚固长度;④《混凝土结构设计规范》(GB50010—2010)中的锚固长度计算公式对于早龄期UHPC中钢筋锚固长度的计算可靠且相对安全,但对于UHPC材料建议放宽规范对抗拉强度的条件限值。
Ultra-High-Performance Concrete(UHPC),a cementitious composite material with high strength,ductility and durability,is now widely used for wet joints of overlapping rebar connections in prefabricated structure.Effective bonding and anchoring of the steel bars in early-age UHPC is an important guarantee for rapid assembly construction.In this paper,pull-out tests were conducted on rebars in UHPC specimens at 3day age,considering the effects of development length on the bond-anchorage behavior.The results show that:(1)two failure patterns appeared in the tests,namely,the rebar pullout failure without yielding and the rebar pullout failure with yielding;(2)for the anchorage design of rebar in 3-day age post-cast UHPC joints,a cover thickness greater than 2.5 times the diameter of the rebar is recommended;(3)for the HRB400 rebar in UHPC at 3-day age,the critical yield development length is 6 times the diameter of the rebar,which effectively reduces the development length compared with that of normal strength concrete;(4)the calculation formula for the development length in the Code for Design of Concrete Structures(GB 50010—2010)is reliable and relatively safe,but it is recommended to relax code limit conditions of tensile strength for UHPC.
作者
袁勇
金鼎立
姚旭朋
荣建
张姣龙
丛松岩
YUAN Yong;JIN Dingli;YAO Xupeng;RONG Jian;ZHANG Jiaolong;CONG Songyan(College of Civil Engineering,Tongji University,Shanghai 200092,China;Shanghai Tongji Green Building Prefabrication Construction Engineering Technology Co.,Ltd.,Shanghai 200092,China;Shanghai Urban Construction Municipal Engineering Group Co.,Ltd.,Shanghai 200065,China)
出处
《结构工程师》
2025年第6期127-135,共9页
Structural Engineers
基金
上海市科学技术委员会科研项目(21DZ1202803,21DZ1202806)。
关键词
超高性能混凝土
早龄期
拉拔试验
粘结锚固强度
临界屈服锚固长度
ultra-high-performance concrete
early-age
pull-out test
bond strength
critical yield development length
