Authors:
Mohamed El-Naqeeb; Salah El-Metwally; Basem Abdelwahed;
Abstract:
Reinforced concrete frames behavior is dependent on its beam-column joint performance. The joint aspect ratio, concrete compressive strength, joint reinforcement detailing, and the column axial stress level are the main key parameters that control the joint performance. The role of the first three parameters are well known. The column axial stress level role is still an open research topic. This study investigates numerically the influence of the column axial stress level on exterior joints. Several connections have been modeled under various column axial stress levels and concrete uniaxial strengths. This study reveals that increasing the column axial stress level led to a delay in the joint cracks' initiation and increase the joint strength. However, the column axial stress level significantly improves the joint shear strength up to a certain level depending on the concrete strength. The beneficial effect of increasing the axial stress level on the joint shear strength is more pronounced with medium or high strength concrete. Furthermore, a proposed equation has been developed for predicting the joint strength considering the variation in axial stress level. The proposed equation gave a better prediction than other researches compared to the reference experimental results.
Keywords:
Reinforced concrete frames; Exterior joints; Nonlinear finite element analysis; Axial stress level; Joint shear strength; Joint cracking.