钢筋混凝土T形截面连续梁穿翼栓锚绕杆自锁U形碳纤维布抗剪加固试验研究

U形纤维布外贴加固混凝土梁易因纤维剥离导致脆性剪切破坏，为此，针对T形截面梁提出了布端绕双杆自锁且用螺栓穿翼锚固的方案，并开展了连续梁负弯矩段受剪加固模型试验。结果表明：加固梁受剪承载力平均提高46.6%，最高达到了61.1%，有效防止了剥离破坏的发生，延性亦有不同程度的改善。绕杆自锁形成的可靠端部锚固使得纤维应变曲线具有“S”形上升的典型特征。既有规范基于常规矩形截面梁封闭粘贴加固试验建立的承载力计算公式对于绕杆锚固开口向上的U形纤维布受剪加固负弯矩T形梁段的适用程度不一，其中英国规范TR55和中国规范GB 50608—2010能够较好地预测主要参数对承载力影响的走势，澳洲规范HB305计算结果平均值与试验值最为接近。

Tests of RC continuous T-beams shear-strengthened with CFRP U-strips around rods through eye bolts penetrating beam flange

Reinforced concrete T-beams externally bonded with FRP U-shaped strips for shear-strengthening are prone to shear failure by FRP debonding. This paper proposed a new scheme in which both ends of each FRP U-strip were self-locked by respectively wrapping around a pair of steel rods (one rod through eye bolts penetrating beam flange). Tests were conducted on the segments of continuous T-beams that were subjected to combined shear and negative moment and strengthened with CFRP U-strips anchored by self-locking. The test results show that by using the proposed scheme, debonding failure can be avoided. The increase in shear capacity is 46.6% in average and up to 61.1% in maximum for the specimen with the largest amount of FRP. Ductility of the strengthened specimens is also improved in varying degrees. The load-strain curve for self-locked FRP features an S-shaped profile. Considering that the existing code formulas are established largely based on the tests of rectangular simple beams strengthened with complete FRP wraps, the applicability of them to predict the shear capacity of T-beam segments strengthened with self-locked CFRP U-strips under negative moment is evaluated. The formulas suggested by the British standard TR55 and Chinese code GB 50608—2010 can predict the influence of main parameters on shear capacity properly. The prediction of shear capacity by Australia guideline HB305 is closest to the test results on the average.