THE EFFECT OF SPACE BAR IN THE TRUSS REINFORCING SYSTEM TO THE FLEXURAL CAPACITY OF REINFORCED CONCRETE BEAMS

Various methods were developed to increase the flexural capacity of reinforced concrete beams. One of method possibility method is by using truss system reinforcement. Therefore, this study aims to analyze the effect of spacing of steel truss system on the behavior of reinforced concrete beam in flexure and crack pattern, and to obtain the theoretical equation to calculate the moment capacity of concrete beams reinforced by steel truss system. This study was conducted experimentally. The number of specimens was twelve, which consist of three control beams (BN) with the vertical stirrups, and nine beams reinforced by steel truss system (BTR). The dimension of all specimens was 150 mm x 2500 mm x 3300 mm. The spacing of steel truss system varied into 0.25d in BTR25, 0.5d in BTR50 and 0.75d in BTR75. The d is the effective depth of the beam. The results of this study showed that the spacing variation of steel truss system can enhance the ultimate capacity of the concrete beams. Compared to BN, the ultimate capacity of BTR25, BTR50 and BTR75 was 10.72%, 7.83% and 4.82%, respectively. In addition, the stiffness of the beam can be also increased due to the effect of steel truss system.