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高强不锈钢绞线网在ECC中的搭接性能

2021-07-11朱俊涛赵奎邹旭岩王新玲李可张哲

土木建筑与环境工程 2021年3期

朱俊涛 赵奎 邹旭岩 王新玲 李可 张哲

摘 要:为探明高强不锈钢绞线网在工程水泥基复合材料(Engineering Cementitious Composites, ECC)中搭接连接的受力特性,并确定其合理的搭接长度,考虑横向钢绞线间距、搭接长度和钢绞线直径等影响因素,对设计制作的39个试件进行了拉拔试验。结果表明:钢绞线网在ECC中的搭接连接有钢绞线拔出和拉断两种破坏模式;横向钢绞线的设置对搭接时的极限拉拔力影响不大,但其滑移量随着横向钢绞线间距的减小而减小;随着搭接长度的增加,达到峰值荷载的滑移量和“搭接刚度”增加,而极限粘结应力则随之降低。通过试验分析,确定了钢绞线网的临界搭接长度,并建立了考虑修正系数β的搭接长度计算公式。

关键词:不锈钢绞线网;工程水泥基复合材料;搭接性能;拉拔试验;搭接长度

中图分类号:TU528.58 文献标志码:A 文章编号:2096-6717(2021)03-0174-09

Abstract: In order to investigate the mechanical characteristics of high strength stainless steel wire mesh in Engineering Cementitious Composites (ECC) and to determine the reasonable lap length, the pullout tests of 39 specimens were carried out by considering the influential factors such as transverse strand spacing, lap length and strand diameter. The results show that there are two failure modes in the lap connection of steel wire mesh in ECC, namely pull out and pull off. The setting of transverse strand has little effect on the ultimate pull-out force, but the slip decreases with the decrease of the transverse strand spacing. With the increase of lap length, the slip amount and "lap stiffness" to peak load increase, while the ultimate bond stress decreases. Based on the experimental analysis, the critical lap length of steel wire mesh is determined, and the calculation formula of lap length considering the correction coefficient β is established.

Keywords: stainless steel wire mesh; Engineering Cementitious Composites (ECC); lap-spliced behavior; pull-out test; splice length

工程水泥基复合材料(Engineered Cementitious Composites,ECC)是一种新型的水泥基复合材料。与普通混凝土相比,由于纤维的橋联作用,使其具有拉伸应变硬化和多缝开裂的特点,提高了结构的延性和耗能能力[1],但强度较低,需要结合增强材料来充分发挥其工作性能。普通钢筋强度低,难以充分发挥ECC的优异性能;纤维编织网性能优越,但经济性和施工性能较差[2-7]。而高强不锈钢绞线具有强度高、耐久性好及运输、施工方便等优点,常与环氧树脂或聚合物砂浆组合用于混凝土结构加固[8]。因此,基于两种材料(高强不锈钢绞线、ECC)的优点,提出高强不锈钢绞线网增强ECC这一新型复合材料[9-11],既充分发挥了ECC和高强不锈钢绞线的优点,又克服了相应增强材料的缺点。……

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