摘要
为充分发挥超高性能混凝土(ultra-high performance concrete,UHPC)在钢混凝土组合梁中的超高力学性能,提出轻型钢-UHPC薄板组合梁结构体系并采用短栓钉进行界面连接。为深入研究UHPC薄板-栓钉界面抗剪的匹配性能,开展了33个静力推出试验,研究了栓钉直径(22 mm和30 mm)、UHPC板厚(35~150 mm)和栓钉长径比(1.0~5.5)等对界面抗剪性能的影响规律。试验结果表明:当直径30 mm的大栓钉长径比从4.0降为2.0时界面受剪承载力变化不大,而栓钉直径从22 mm增加到30 mm时,长径比1.5以下短钉和2.0以上长钉的受剪承载力分别增加25%和94%;当大直径栓钉的长径比从4.0减小到1.5和1.0时,界面破坏模式从栓钉完全剪断转变为栓钉部分剪断;UHPC拔出或完全拔出等破坏,其受剪承载力最大降低可达40%;栓钉上方保护层厚度为30 mm时,UHPC板表面无劈裂裂缝,进一步减小保护层厚度至15 mm和5 mm时,界面受剪承载力仅降低7%;与普通混凝土中栓钉抗剪刚度相比,UHPC中短钉的界面抗剪刚度提高62%以上。进一步开展了UHPC薄板中短钉的受剪承载力和受剪刚度的分析,并与普通混凝土中栓钉的抗剪性能进行对比,揭示了栓钉-UHPC薄板相互作用机理。将试验结果与各国规范中栓钉受剪承载力计算结果进行对比,发现规范ACI 318和PCI能够较好地预测UHPC薄板中栓钉的受剪承载力。
In order to fully use the high strength of ultra high performance concrete(UHPC)in steel-concrete composite bridges,a composite system comprising the short stud connections was proposed.To explore the shear behavior of ultrathin UHPC slab-stud connections,thirty-three push-out specimens were tested based on the studs of 22 mm and 30 mm in slabs of 35-150 mm giving an aspect ratio of 1.0-5.5.Test results indicate that decreasing the large-diameter stud aspect ratio from 4.0 to 2.0 marginally influences the shear resistance of studs whereas with an increase in stud diameter,the longitudinal shear strength improves by 25%and 94%for short and long studs respectively.When stud aspect ratio decreases from 4.0 to 1.5 and 1.0,the failure of specimens changes from the full fracture of studs to the partial fracture of studs with UHPC pry-out and the complete pry-out of UHPC,in which the shear strength reduces by 40%at most.The cover thickness of more than 30 mm over the stud head has little influence on the interfacial shear strength while only 7%reduction in the shear resistance is found for 15-mm-thick and 5-mmthick cover thickness.Compared with the studs in normal concrete(NC),the short stud-UHPC connections are 62%stiffer in slip than their normal concrete counterparts.Moreover,the shear strength and shear stiffness were analyzed comprehensively.Comparisons between the stud-NC and stud-UHPC were also made based on test results and the interaction mechanisms were also illustrated.Finally,the shear strengths calculated by different design codes were also compared with the test results,and found that the ACI 318 and PCI design codes could accurately predict the shear strength of short studs in the thin UHPC slabs.
作者
徐启智
王景全
谭豫卿
陆凯卫
姚一鸣
XU Qizhi;WANG Jingquan;TAN Yuqing;LU Kaiwei;YAO Yiming(College of Civil Engineering,Nanjing Tech University,Nanjing 211800,China;State Key Laboratory of Safety,Durability and Healthy Operation of Long Span Bridges,Nanjing 210037,China;College of Civil Engineering,Southeast University,Nanjing 211189,China)
出处
《建筑结构学报》
EI
CAS
CSCD
北大核心
2024年第S01期291-303,共13页
Journal of Building Structures
基金
国家自然科学基金青年基金项目(52308175)
江苏省青年科技人才托举工程项目(JSTJ-2023-JS002)
