CFRP加固钢筋混凝土梁端部剥离破坏的试验研究

Experimental research on debonding failure of plate-end of RC beam strengthened with CFRP

经受拉边粘贴CFRP作抗弯加固的钢筋混凝土梁,除发生正截面破坏模式外,经常会出现一种早期纤维端部的剥离破坏,导致纤维抗拉强度不能有效利用甚至加固失效.通过8根抗弯加固后梁的试验研究,认为剥离破坏是由于纤维端部应力集中产生的界面剪应力、正应力和弯剪斜裂缝基部产生的粘结锚固应力综合作用造成的.文章描述了界面剪应力的分布规律,指出混凝土强度、粘贴纤维层数尤其是无板长度是影响界面剪应力的主要因素,从而为进一步研究防止或延缓纤维端部剥离破坏的有效措施提供科学依据.

In case of RC members strengthened by means of externally bonded CFRP plate, a premature failure which is debonding failure of CFRP-end can be detected in addition to the normal section failure mode. This failure makes the tension strength of CFRP can not be used efficiently, and even leads to the invalidation of RC beam strengthened with CFRP. The experiment of 8 RC beams strengthened with CFRP indicates that debonding failure mainly due to shear stress, normal stress caused by stress concentration and bonding-peeling stress near crack base in the CFRP-end which leads to bearing-shearing. The rule of the interfacial shear stress distribution also has been described. The results show that unsheeted length layer number and concrete strength are the main factors which have the influence on interfacial shear stress. It provides scientific foundation for study effective measurements to prevent or delay debonding failure of RC beam strengthened with CFRP.