底面外贴钢筋加固混凝土梁抗弯性能试验研究

Experimental Research on Flexural Behavior of RC Beams Strengthened by External Rebars at Bottom Surface

通过1根控制试验梁与5根加固梁的静力试验,对底面外贴钢筋加固混凝土梁的抗弯性能进行试验研究。讨论加固试验梁在不同加固技术参数下(增补钢筋面积、锚栓布置与数量)的裂缝开展、刚度变化和承载力提高等情况,并分析各参数因素对试验梁加固的影响规律。试验结果表明:底面外贴钢筋加固试验梁经加固后其开裂荷载、刚度和抗弯承载力均显著提高;从跨中截面的混凝土应变规律可知,正截面应变符合平截面假定。提出外贴钢筋加固混凝土梁正截面抗弯承载力计算公式,由该公式计算的正截面承载力计算值与试验值吻合良好。

The experiments on the flexural behavior of RC beams strengthened by external rebars at bottom surface are conducted through a control beam and 5 strengthened beams. The cracking propagation, stiffness change, and improvement of load bearing capacity with different parameters （area of added reinforcement, arrangement and numbers of anchoring bar） for strengthened test beams are discussed. The test result shows that （ 1 ） the cracking load, stiffness and flexural bearing capacity of the test beams are improved significantly after adding external rebars; （2） from the concrete strain pattern of section at mid-span, it can be inferred that the strain in normal section accords with the plane section assumption; （3） the formula for calculating the flexural capacity of normal section of RC beams strengthened by external rebars is proposed, and the values calculated by the presented formula are in good agreement with the test values.