SHEAR STRENGTH OF CONCRETE EMBEDDED BEAMS AND HOLLOW BLOCK SLABS | ||
| The International Conference on Civil and Architecture Engineering | ||
| Article 26, Volume 7, 7th International Conference on Civil and Architecture Engineering, May 2008, Pages 23-51 PDF (1.6 M) | ||
| Document Type: Original Article | ||
| DOI: 10.21608/iccae.2008.45503 | ||
| Author | ||
| AYMAN HUSSEIN HOSNY KHALIL | ||
| Associate Professor, Structural Engineering Department, Ain Shams University, Cairo, Egypt. | ||
| Abstract | ||
| In Egypt, it is a common practice to utilize floor systems consisting of hollow block slabs resting on embedded beams having the same depth. For the embedded beams and the hollow block slabs, the current Egyptian Code requires that the shear resistance to be solely provided by concrete with no dependence on any form of shear reinforcement. Four international code requirements were reviewed and no similar provisions were found. In this paper, the shear strength of embedded beams and hollow block slabs with intermediate length (shear span-to-depth ratio of approximately 5) is evaluated. Nine medium-scale simply-supported conventionally reinforced concrete embedded beams and five full-scale hollow block one way slabs with normal concrete strength subjected to three-point monotonic loading were experimentally loaded to failure. The specimens were typically proportioned so that shear failure would preclude flexural failure. The study examines the shear strength of the tested specimens with special emphasize on the effect of shear reinforcement in the form of vertical stirrups with varying shapes, configuration, and amount. During testing, deflections, strains in main reinforcement, concrete, and stirrups were monitored. Recorded capacities of specimens with shear reinforcement reached as high as 300% of those without shear reinforcement. Laboratory recorded shear strengths at failure are compared with theoretical strengths calculated according to the current Egyptian Code procedures and the reviewed international codes. Further, the shear capacity of tested specimens was assessed in the light of the modified compression field theory. Test results clearly demonstrated that the shear reinforcement significantly improved the shear capacity and enhanced the ductility of the tested specimens. As such, the study concludes that the vertical stirrups are effective as shear reinforcement in embedded beams and in one-way hollow block slabs. A simplified empirical formula for predicting the shear strength of such elements is also proposed based on the Egyptian Code provisions. | ||
| Keywords | ||
| Shear Strength; embedded beams; hollow block slabs; ribbed slabs; shear reinforcement; Stirrups; modified compression field theory | ||
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