Fayed Sabry, Ghalla Mohamed, Hu Jong Wan, Mlybari Ehab A, Albogami Abdullah, Yehia Saad A
Civil Engineering Department, Faculty of Engineering, Kafrelsheikh University, Kafr El-Sheikh 33516, Egypt.
Department of Civil and Environmental Engineering, Incheon National University, Incheon 22012, Republic of Korea.
Materials (Basel). 2024 Nov 21;17(23):5701. doi: 10.3390/ma17235701.
In this study, shear-critical reinforced concrete (RC) beams were strengthened by combining the prestressing and near-surface mounted (NSM) rods approaches. The potential danger of failure in such RC beams is a substantial concern as it is considered a potential threat. This study addresses its careful mitigation through experimental identification and numerical analysis to enhance the safety and sustainability of buildings by reducing the probability of failure risk for these RC beams. Nine of the ten RC beams that were tested had strengthened, and one had not. Internal prestressing (IP) within the beam body, external prestressing NSM (PNSM), internal embedment (IE) inside the beam with or without prestressing, and NSM are the strengthening technologies that were employed. The range of the extra shear reinforcement ratios (μs) was 0.87% to 1.60%. We investigated how strengthened beams behaved structurally in terms of the cracking load, ultimate load, load-deflection response, ultimate deflection, and stiffness. The insertion of five pairs of PNSM rods (μs = 1.45%) and five pairs of IP rods (μs = 1.6%), respectively, increased the beams' shear capacity by 57.8% and 70.4%. Shear capacity increased by 23.2% when three pairs of IE rods (μs = 1.02%) were installed. The prestressing location had an impact on shear capacity, with the interior case surpassing the external one. Compared to the control, the stiffness of the strengthened beams rose by 20%, 82%, and 84.4% when three, four, or five pairs of internal prestressing rods were added. A formula is proposed to calculate the shear capacity of all beams strengthened using various methods.
在本研究中，通过结合预应力和近表面安装（NSM）钢筋方法对抗剪关键钢筋混凝土（RC）梁进行了加固。此类RC梁潜在的破坏危险是一个重大问题，因为它被视为一种潜在威胁。本研究通过实验识别和数值分析对其进行了仔细的缓解，以通过降低这些RC梁的破坏风险概率来提高建筑物的安全性和可持续性。测试的十根RC梁中有九根进行了加固，一根未加固。采用的加固技术包括梁体内的内部预应力（IP）、外部预应力NSM（PNSM）、梁内有或无预应力的内部嵌入（IE）以及NSM。额外抗剪配筋率（μs）的范围为0.87%至1.60%。我们研究了加固梁在开裂荷载、极限荷载、荷载-挠度响应、极限挠度和刚度方面的结构性能。分别插入五对PNSM钢筋（μs = 1.45%）和五对IP钢筋（μs = 1.6%），使梁的抗剪承载力分别提高了57.8%和70.4%。安装三对IE钢筋（μs = 1.02%）时，抗剪承载力提高了23.2%。预应力位置对抗剪承载力有影响，内部情况优于外部情况。与对照梁相比，添加三对、四对或五对内部预应力钢筋时，加固梁的刚度分别提高了20%、82%和84.4%。提出了一个公式来计算采用各种方法加固的所有梁的抗剪承载力。
