Improving RC Beam-Column Joints Characteristics Using Different Reinforcement Details

Abstract

This paper aims to study the effect of concrete confining using a new style of internal closed stirrups and longitudinal steel bars along with the middle third of the beam length of the beam-column joints. Also, the influence of concrete compressive strength was investigated using three types of concrete normal strength concrete (NSC), high strength concrete (HSC), and steel fiber concrete (SFRC). Nine reinforced concrete specimens with the same dimensions are divided into three groups according to the concrete type with different reinforcement details in the middle third of the specimen’s length. Four specimens with (NSC) represent the first group, while three specimens consist in the second group with (HSC). Steel fiber of 2% was used in two specimens of the third group (SFRC). The test results showed that using additional reinforcement steel bars as a closed stirrup arranged about the neutral axis improved the flexural strength and enhanced the load-carrying capacity for the reinforced concrete joints. The ultimate capacity of the joints increased by a range (34 to 50) % more than the control specimen. The ultimate strength was also increased for the specimens due to using high-strength concrete with a range (of 13 to 66) % compared with the specimen of normal compressive strength.