Experimental study on flexural behaviour of prefabricated concrete beams with double-grouted sleeves
Experimental study on flexural behaviour of prefabricated concrete beams with double-grouted sleeves
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DOI：
10.1016/j.engstruct.2021.113237
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发表时间：
2021-09-24
影响因子：
5.5
通讯作者：
Zhang, Mingzhong
中科院分区：
文献类型：
--
作者：
Lu, Zhiwei;Wu, Bin;Zhang, Mingzhong
为减少现场混凝土浇筑量，加快施工进度，提出了一种新型的双浆套连接预制混凝土梁。本文对三点和四点弯曲预制梁的抗弯性能进行了系统的试验研究。总共测试了11个具有不同类型灌浆套管、下过渡杆直径、填料长度、填料数量、填料类型、连接类型和灌浆套管长度的样本，以及两个现浇样本。结果表明，钢套管在梁表现令人满意，螺纹有助于增加其初始刚度。由于界面效应的影响，所有预制梁的首次开裂荷载均低于参考梁。随着下过渡筋直径的增加，预制试件的三点弯曲屈服和极限承载力分别提高了9.0%和21.0%。在三点弯曲和四点弯曲条件下，双灌浆套管梁的最大裂缝宽度分别比参考梁大41.2%和28.6%，表现出更好的延性。填料区的应力集中发生由于不连续的刚度，但随着下过渡杆的直径的增加而减小。双钢套筒梁比现浇梁的正常使用荷载限值略低。当填料长度增加20 mm时，双灌浆套管梁的最大裂缝宽度增加55.6%。现浇梁承载力计算方法适用于单套或双套灌浆预制梁的承载力计算。
A novel precast concrete beam connected using double-grouted sleeves was developed to reduce pouring concrete on-site and expedite construction. This paper presents a systematic experimental study on the flexural behaviour of precast beams subjected to three-point and four-point bending. In total, 11 specimens with different types of grouted sleeves, diameters of the lower transition bar, filler lengths, numbers of filler, types of filler, types of connection and lengths of the grouted sleeve, and two cast-in-situ specimens were tested. The results indicated that the steel sleeves in the beams performed satisfactorily, and threads aided in increasing their initial stiffness. The first cracking load of all the prefabricated beams was lower than that of the reference beams owing to the interface effect. With an increase in the diameter of the lower transition bar, the yield and ultimate bearing capacities of the precast specimen under three-point bending increased by 9.0% and 21.0%, respectively. The beams with double-grouted sleeves exhibited better ductility with maximum crack widths that were 41.2% and 28.6% larger than that of the reference beam under three-point and four-point bending, respectively. The stress concentration in the filler region occurred owing to discontinuous stiffness but decreased with an increase in the diameter of the lower transition bar. The beam with double steel sleeves achieved a slightly lower normal service load limit than the cast-in-place beam. As the filler length increased by 20 mm, the maximum crack width of the beams with double-grouted sleeves increased by 55.6%. The method for the cast-in-place beam was adequate for calculating the load-bearing capacity of the prefabricated beam with double-grouted sleeves or a single-grouted sleeve.