The effect of steel hollow section size on flexural capacity and ductility of truss reinforced concrete beams

This research aims to evaluate the effect of variations in steel hollow section size on flexural capacity and ductility of concrete beams reinforced with steel truss. In line with these findings, three concrete beam specimens with the same cross-sectional size, namely 150 mm x 700 mm, and a length of 2000 mm, were prepared. Beams were reinforced with trusses made of mortar-filled hollow sections of three different sizes. The load was applied using the central loading method at mid-span. The main parameters observed included crack patterns, flexural capacity, bending moment-displacement relationship, and ductility index. The test results showed that increasing steel hollow section size significantly contributed to improving flexural capacity and stiffness of beams. However, the increase in steel hollow section size was not directly related to increasing ductility. These findings confirm that variations in steel hollow section dimensions directly affect the structural behavior of concrete beams, making it a viable alternative reinforcement method, effective and applicable in building and infrastructure construction.