In an effort to enhance the seismic capacity of non-seismically designed reinforced concrete (RC) columns, this study proposes a retrofit method for non-seismically designed RC columns using hybrid FRP (HFRP) sheets consisting of glass and carbon FRPs. HFRP sheets can be installed for retrofitting the RC columns in a structure employing electric equipment such as metro stations or tunnels. With the assumption that the cyclic behavior of RC columns retrofitted with wrapping HFRP sheets is dependent on their numbers of plies and their wrapping lengths, full-scale cyclic tests with a total of five specimens were carried out to verify their seismic performance and to confirm the effects of HFRP sheets. In addition, this study aims to construct an analytical model to predict the cyclic behavior of HFRP retrofitted RC columns for more practical applications. The analytical model can properly capture the cracking and maximum strength with reasonable tolerance and also well simulate the hysteresis loops including pinching phenomenon as well as confinement effect of wrapping HFRP sheets. The BC specimen without employing HFRP sheets suffers the lowest inelastic deformation following the strength degradation with the early spalling of concrete cover. The test and analytical results present that wrapping HFRP sheets results in slight increase in the initial stiffness whereas cracking and maximum strength enhanced up to 15% since the HFRP sheet delay the crack propagation. The specimens wrapped with HFRP sheets develops the significant increase in the deformation capacities due to the increase in the confinement of concrete around plastic hinge regions. For the maximum deformation capacity of retrofitted RC columns, the number of plies of HFRP sheets wrapped at the expected plastic hinge regions is more influential than their length. The deformation capacity of RC columns wrapping two plies of HFRP are enhanced up to at least 2.1 times of that of a non-seismically design bare RC column.

为了提高非抗震设计的钢筋混凝土柱的抗震能力，本研究提出了一种由玻璃和碳纤维增强塑料组成的混合FRP（HFRP）板对非抗震设计的RC柱进行改造的方法。可以安装HFRP板，以在采用电气设备（如地铁站或隧道）的结构中翻新RC柱。假设用包裹的HFRP板加固的RC柱的循环性能取决于其层数和包裹的长度，共进行了五个试样的全尺寸循环试验，以验证其抗震性能并确认其抗震性能。 HFRP床单的效果。此外，本研究旨在构建一个分析模型，以预测HFRP加固RC柱的循环行为，以更实际地应用。该分析模型可以合理地捕捉开裂和最大强度，并具有合理的公差，并且可以很好地模拟磁滞回线，包括收缩现象以及包裹HFRP片材的约束效果。在不使用HFRP片材的情况下，随着强度的降低以及混凝土覆层的早期剥落，不使用HFRP片材的BC试样的弹性变形最小。测试和分析结果表明，包裹HFRP片材会导致初始刚度略有增加，而由于HFRP片材延迟了裂纹扩展，因此开裂和最大强度提高了15％。包裹有HFRP薄板的试样的变形能力显着提高，这是由于围绕塑料铰链区域的混凝土约束力增加所致。为了获得最大的变形RC柱变形能力，在预期的塑料铰链区域包裹的HFRP板的层数比其长度更具影响力。包裹两层HFRP的RC柱的变形能力至少提高到非抗震设计的裸RC柱的变形能力的2.1倍。