Effect of Repeated Loads on Steel -Concrete Composite Beams with High Strength Reinforced Concrete

Abstract

The present study utilized an experimental tests to investigate the effects of using High Strength Concrete (HSC) on ultimate resistance, deflection and slip of steel-concrete composite beam under monotonic and repeated loads. Sixteen beams divided into four groups having concrete with compressive strength of 25, 42.6, 43.3 and 43.9MPa investigated experimentally. Results indicated that the use of HSC increases the carrying loading capacity of the beams by about 18.82 % and 52.91 % under monotonic and repeated loads, respectively. The beam resistance decreased under repeated load in comparison with monotonic load by about 5 % to 28.53 %. Use the fiber increases the ultimate strength by about 10 % to 28.65 %, and decrease the deflection and slipping by 15 % and 26.5 %, respectively. The ultimate strength estimated experimentally are less than the AISC-LRFD specifications’ formulas.