通过不同高延性混凝土(HDC)加固厚度，对10根受损严重的钢筋混凝土无腹筋梁采用HDC进行加固，并进行了重复荷载作用下正截面受弯试验，研究了不同厚度的HDC对受损无腹筋梁的受弯承载力以及变形性能的影响。试验梁采用三面U形加固方式，试验过程中观察加固梁的裂缝分布形态、荷载-位移曲线等试验变化情况。试验结果表明，采用HDC加固钢筋混凝土梁，会使梁的破坏形态由脆性破坏向延性破坏转变，加固梁的承载力、延性和耗能能力都得到显著提高。与HDC加固层厚度为0的梁相比，加固厚度为1 cm、15 cm和2 cm的梁，承载力分别提高了198%、327%以及463%，而残余变形值分别减少了896%、133%和2047%。根据加载试验得出的试验结果，以及通过将受压区曲线应力图形等效为矩形应力图形的方法，推导出了简单实用的不同HDC厚度加固受损混凝土无腹筋梁在重复荷载下的极限承载公式，且计算值和试验值吻合较好。
Abstract
Here, 10 severely damaged concrete beams without web reinforcement were strengthened by using high ductility concrete (HDC) with different thicknesses.The normal section bending tests under repeated load were conducted to study effects of HDC with different thicknesses on flexural load-bearing capacity and deformation performance of damaged beams without web reinforcement.In tests, beams’ crack distribution state and load-displacement curve were observed.The test results showed that the failure mode of concrete beams strengthened with HDC can change from brittle failure to ductile one, and their load-bearing capacity, ductility and energy dissipation capacity are significantly improved; compared with the beam with HDC reinforcement layer thickness of 0 cm, load-bearing capacities of beams with HDC thickness of 1 cm, 1.5 cm and 2 cm are increased by 19.8%, 32.7% and 46.3%, respectively, while their residual deformations are reduced by 8.96%, 13.3% and 20.47%, respectively.According to loading test results and the method of the curve stress figure of compression zone being equivalent to rectangular stress figure, a simple and practical ultimate load-bearing formula of damaged concrete beams without web reinforcement strengthened with different HDC thicknesses under repeated load was derived, and its calculation values agree better with test ones.
关键词
高延性混凝土（HDC） /
受损混凝土无腹筋梁 /
重复荷载 /
受弯性能 /
受弯承载力
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Key words
high ductile concrete (HDC) /
damaged concrete beam without web reinforcement /
repeated load /
flexural performance /
flexural load-bearing capacity
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