内嵌CFRP筋加固混凝土梁桥界面特性研究的宽缺口梁法

Research on Interface Properties of Concrete Beam Bridges Strengthened with Near-surface Mounted Carbon Fiber Reinforced Plastic Bar by Using Wide-notch Concrete Beam Method

为了使CFRP筋加固混凝土梁桥界面特性研究更精确,针对混凝土梁作为受弯构件受力时,不考虑混凝土抗拉强度的基本假定,共浇筑19根钢筋混凝土梁,研究和对比CFRP筋加固宽缺口混凝土梁、CFRP筋加固不带缺口的混凝土梁和未加固的对比混凝土梁的力学特性、CFRP筋-混凝土界面的滑移特性及粘结剪力大小。研究结果表明:CFRP筋对宽缺口混凝土梁的加固效果和对普通混凝土梁的加固效果相近;可以用宽缺口梁来研究CFRP筋-混凝土界面上的粘结剪应力及滑移特性,CFRP筋-混凝土界面滑移和应变易测,外露的CFRP筋受力明确;回归得到的CFRP筋-混凝土界面的平均剪应力与界面剥离承载力的表达式简洁,可用于工程实践。

On account of the basic assumption of no-load bearing of concrete tensile region when RC beam as flexural component was bended, in order to make interface property research of concrete beam bridge with CFRP bar more accurate, 19 concrete beams were poured for researching and comparing slip characteristics and bond shear size of CFRP bar-concrete interface and mechanical properties of no-strengthened concrete beam, the strengthened concrete beam with CFRP bar and strengthened wide-notch concrete beam with CFRP bar. The results show that the strengthening effect of CFRP bar on wide-notch concrete beam is quite the same as that on common concrete beam. It is advantageous to use wide-notch concrete beam to research the bond-slip characteristics of CFRP bar-concrete interface with easy measure slip and strain of CFRP bar-concrete interface, and clear exposed CFRP bar stress. The expressions of averageshearing stress and interface bearing capacity by regression are accurate and succinct, which can be used in engineering practice.