高強度混凝土含開孔深梁之修復

Repairing of High-Strength Concrete Deep Beams with Web Openings

本研究旨在以貼碳纖維(CFRP)或低壓灌注環氧樹脂(LPEI)方式修復含開孔深梁。共製作18支含開孔深梁進行兩次剪力強度試驗，第1次試驗中，6支控制梁不含CFRP，其餘12支梁在試體兩面包覆兩層寬度40mm之CFRP，6支沿水平方向補強，另6支沿垂直方向補強。第1次試驗結果顯示，開孔尺寸60×40mm深梁之剪力強度較開孔尺寸68×68mm之剪力強度高出17%。水平方向包覆碳纖維之試體，其平均約可提升6%之剪力強度，垂直方向包覆碳纖維之試體，則平均約可提升8%之剪力強度。本研究於第1次試驗後，選取12支剪力破壞之含開孔深梁，6支控制梁於正反面各貼1層CFRP，另6支則以LPEI修復並再次進行試驗，比較兩次試驗結果得知，以LPEI修復之試體平均可提升18%剪力強度，而以貼1層CFRP方式修復剪力破壞之含開孔深梁應仍屬可行。

The objective of this study was to investigate the repairing effectivenessof carbon fiber reinforced polymer (CFRP) or low pressure epoxy injection(LPEI) on the deep beams with web openings. A total of 18 high-strengthconcrete deep beams with web openings were tested. Six controlled beamswere not strengthened by CFRP; twelve beams were wrapped with twolayers of 40 mm wide CFRP strip on both sides of specimens, and; six ofthem strengthened in the horizontal direction and the others in the verticaldirection. In the first phase of test, all beams were failed by shear. Test resultsindicated the shear strengths of deep beams with openings sized 40 mmby 60 mm were about 17% higher than those with openings sized 68 mm by 68 mm. The shear strengths of deep beams with web openings strengthenedby CFRP wrapped in the horizontal direction can be enhanced by about6%, the shear strengths of deep beams with web openings strengthened byCFRP wrapped in the vertical direction can be enhanced by about 8%.After the first phase of test, 12 deep beams with web openings were chosento repair and then tested once more. Six controlled beams were wrappedwith one layer of CFRP on both sides of specimens. The other beams wererepaired by low pressure epoxy injection (LPEI). The results in the secondphase of test indicate that the shear strengths of CFRP strengthenedbeams can be enhanced about 18% by LPEI. Moreover, they showed that sixcontrolled beams may be repaired by being wholly wrapped with one layerof CFRP on both sides.