Prediction of Shear Strength of Beam-Column Joint with Glass Fiber Reinforced Polymer Bars Using Response Surface Methodology

The beam-column joints (BCJs) are one of the critical elements in reinforced concrete structures, having a significant impact on the seismic response of structures. Traditionally, the strong column-weak beam concept has been used during design, which assumes the BCJ as a rigid connection. However, this approach can lead to brittle shear failure at the joint under seismic loads, highlighting the importance of accurately estimating the joint shear strength (JSS) of BCJs to ensure structural safety. There has been a growing interest in replacing steel reinforcement with sustainable alternatives such as glass fiber reinforced polymer (GFRP) bars. The advantages of GFRP bars include reduced corrosion, improved service life, and lower maintenance costs. While some studies have evaluated the seismic behaviour of BCJs reinforced with GFRP bars, limited research has been conducted on determining the JSS of GFRP reinforced BCJs. The current design codes for estimating JSS rely solely on empirical formulae that consider the effect of concrete strength. However, this approach neglects the influence of other critical factors such as geometry, yield strength of steel, and longitudinal and transverse reinforcements, which are crucial for accurately predicting JSS. This paper proposes a novel approach for predicting JSS in BCJs reinforced with GFRP bars using the response surface methodology. To achieve this, finite element models of BCJs are developed using ABAQUS software, and their JSS at failure is evaluated. The experimental data from the literature are also incorporated to perform surrogate modelling of GFRP reinforced BCJs. The efficiency of the surrogate model is statistically evaluated using the coefficient of determination. Overall, this study presents more accurate approach for predicting shear strength of GFRP reinforced BCJs by considering all possible influencing parameters. This will help in preventing brittle shear failure and improving the durability of structure.