Shear Failure Control of RC Box Beams Using Internal Transverse Diaphragms

The rapid development in construction and material technology arising the needs for simple techniques to increase the shear strength of RC box beams. This paper is devoted to investigating experimentally the structural behavior of RC box beams which have internal in-plane solid diaphragms under the effect of shear stresses. For this purpose, four beam specimens with (200x300x1200mm) dimensions are poured using normal strength concrete of class ( f' c =22MPa) and longitudinal flexural steel of class ( f y =410MPa) without transverse reinforcement (stirrups). Three of these specimens were a box with or without different locations of internal diaphragms and one of them was a solid. The number of the internal diaphragms is the major variable adopted in this study, while, the other variables are kept constant for all tested specimens. The experimental results indicated that the shear strength is increased for about (35%) to (47%) for beams containing internal in-plane diaphragms in comparison with the reference beam. Also, the change of beam section from box section to solid section led to increasing the capacity for about (100%). Keywords: Shear Failure, Box Beam, Reinforced Concrete, Diaphragms, ACI-318 Code DOI: 10.7176/CER/12-8-06 Publication date: August 31 st 2020