Bencardino Francesco, Nisticò Mattia
Department of Civil Engineering, University of Calabria, Via P. Bucci, Cubo 39B, 87036 Rende, Cosenza, Italy.
Materials (Basel). 2023 Feb 10;16(4):1510. doi: 10.3390/ma16041510.
Steel-reinforced grout (SRG) systems are effective methods for the flexural strengthening of reinforced concrete (RC) beams. In this study, the effect of a limited number of repeated loads on the structural response and debonding evolution of strengthened beams was experimentally investigated. The number of available research concerning the cyclic behavior of SRG-strengthened members is quite limited and this research attempts to cover this knowledge. A total of ten full-scale RC beam specimens were tested under a four-point bending scheme. The effectiveness of the traditional externally bonded (EB) strengthening technique was compared with a promising innovative technique referred to as inhibiting/repairing/strengthening (IRS). The test variables included the use of two SRG configurations using high and low steel strip density. The experimental results revealed that the performance of the beams was largely dependent on the spacing of the steel strands within the reinforcing strip. Under repeated loading, the debonding of the external system takes place when steel fiber with high mass per unit of area was used. By increasing the matrix impregnation of the steel strip, the composite system was not affected by debonding. Further, the efficiency in terms of flexure enhancement, local and global ductility performance and energy dissipation of the beams are also discussed.
钢纤维增强灌浆（SRG）系统是钢筋混凝土（RC）梁抗弯加固的有效方法。本研究通过试验研究了有限次数的重复荷载对加固梁结构响应和脱粘演化的影响。关于SRG加固构件循环性能的现有研究数量相当有限，本研究试图填补这一知识空白。总共十个全尺寸RC梁试件在四点弯曲试验方案下进行了测试。将传统的外部粘贴（EB）加固技术的有效性与一种有前景的创新技术——抑制/修复/加固（IRS）进行了比较。试验变量包括使用两种不同钢带密度的SRG配置。试验结果表明，梁的性能在很大程度上取决于加固带内钢绞线的间距。在重复荷载作用下，当使用单位面积质量较高的钢纤维时，外部系统会发生脱粘。通过增加钢带的基体浸渍，复合系统不受脱粘影响。此外，还讨论了梁在抗弯增强、局部和整体延性性能以及能量耗散方面的效率。
