钢筋网复合砂浆加固受弯足尺RC梁二次受力试验研究

Experimental study on RC beam reinforced by reinforcing steel bar mesh mortar subjected to secondary load

本文对钢筋网复合砂浆加固的受弯足尺混凝土梁二次受力进行了试验研究。试验包括10根用钢筋网复合砂浆加固的加固试验梁和4根未加固的对比试验梁。试验梁采用三面U形加固形式,量测了试验梁的挠度,钢筋、混凝土及复合砂浆应变等。通过改变加固钢筋的直径、数量及强度等级,研究了本加固法对二次受力的RC梁的极限承载力,破坏形态,截面刚度及裂缝分布等的影响。试验结果表明,钢筋网复合砂浆薄层加固是一种有效的加固方法,能够显著地提高钢筋混凝土梁的抗弯承载力、截面刚度以及抗裂性能;另外,当梁底加固纵筋的配筋率超过“界限配筋率时”,加固梁可能发生脆性的剥离破坏。

In this paper, an experimental study is conducted on the flexural behavior of reinforced concrete beam by high capability ferrocement mortar subjected to secondary load. Based on the comparision between test results of ten beams reinforced by ferrocement mortar and four general beams, beams reinforced with U-shape, load-deflection, strain of concrete, steel and mortar are measured. Through changing the diameter, number and intension grade of reinforcing steel bar, the effect of the strengthening measure on the ultimate load is tested on secondary load＇s RC beams, mode of failure , section stiffness and fissure distribution. The results proves that ferrocement motar technology is an efficient method to reinforce RC beam, which can obviously increase the load-bearing capacity, section stiffness and crack-resisting behavior. In addition, when the reinforcement ratio of strengthening bar are bigger than ＂eccentricity reinforcement ratio＂, the strips destruction may possibly occur on the reinforced beam.