EFFECTIVE WIDTH OF REINFORCED CONCRETE SLAB IN MONO- SYMMETRIC STEEL-CONCRETE COMPOSITE BEAM

Abstract

This research was implemented to investigate the effect of using a mono-symmetrical steel section with different slenderness ratios on the effective slab width value of composite beams. In addition, to investigate the effect of using the upper steel reinforcement mesh on both the effective concrete slab width and slip value. Also, to investigate the validity of the effect of concrete slab thickness on the effective slab width value and the validity of applying the equation developed by Lasheen et al. on the mono-symmetrical steel section. Finally, to investigate the validity of using the angle shear connector in steel-concrete composite beams and compares their behaviour with the channel shear connector. Throughout this research program, all parameters affecting the effective slab width was investigated both experimentally and numerically. Also, the effective width was calculated according to the international codes (i.e., ANSI/AISC 360-15, CAN/CSA S16-14 and the Eurocode 4; CEN 2004) and compared with the codes limit. Besides, the effect of the upper steel reinforcement mesh is studied with different ratios on the behaviour of steel-concrete composite beams. The effect of the upper steel reinforcement mesh was investigated on the ultimate load capacity, deflection values, strain values, slip values at the steel-concrete interface and the effective concrete slab width of steel-concrete composite beams. The results of this study will allow engineers to predict behaviour accurately on both elastic and ultimate stages for mono-symmetric steel-concrete composite beams. The experimental program consisted of testing ten mono-symmetrical steel beams. Six beams have concrete slab thickness of 80 mm. For the other beams, two beams with a concrete slab thickness of 120 mm and two beams with a concrete slab thickness of 140 mm. Two types of shear connectors are used to provide the connection between the concrete slab and steel section, namely; channel and angle shear connectors. Five steel beams are connected to the concrete slab using channel shear connector, while other five steel beams are provided with angle shear connector. The main testing parameters are the different shapes of shear connectors (i.e., channel and angle), span-to-beam depth ratio (L/d), span-to-radius of gyration of steel section ratio (L/rs), the existence of upper steel reinforcement mesh and the thickness of the concrete slab (ts). All beams were cast using the typical normal weight concrete.