Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : Deep beams

Effect of Shear Span-Depth Ratio on Shear Strength of Porcelanite Lightweight Aggregate Reinforced Concrete Deep Beams Strengthened by Externally Bonded CFRP Strips

K.F. Sarsam; N.A.M. Al-Bayati; A.S. Mohammed

Engineering and Technology Journal, 2017, Volume 35, Issue 3, Pages 267-275

This paper presents an experimental investigation of structural behaviour of reinforced concrete deep beams strengthened in shear by CFRP strips. The experimental program consisted of fabricating, casting and testing of nine identical porcelainte lightweight aggregate reinforced concrete deep beams. Three of the tested deep beams were unstrenghtened to serve as reference beams, while the remaining beams were tested after being strengthened using CFRP strips in two different orientations (vertical and horizontal). The locally available natural porcelanite aggregate is used to produce lightweight aggregate concrete. The beams were designed to satisfy the requirements of ACI 318M- 14 building code. In order to insure shear failure modes, adequate flexural steel reinforcement were provided. Effect of three different values of shear span to effective depth ratio (a/d =1.0, 0.8, 1.2) were selected. All beams have been tested as a simply supported beams subjected to two concentrated points loading. The beam specimens were tested up to failure under monotonic loads. The experimental work showed that the failure load increases as the shear span to effective depth ratio deceases. As the shear span to effective depth ratio decreased from 1.0 to 0.8, the percentage of increase in the ultimate load was about 24%. In addition, the diagonal compression strut crack of unstrenghtened control beams was changed to several diagonal cracks at mid depth within the shear span of the strengthened beams and exhibited more ductile failure mode.

Structural Behavior of Self Compacting Reinforced Concrete Deep Beams Containing Openings

Nabeel A. AL-Bayati; Bassman R. Muhammad; Ahmed Salam Hasan

Engineering and Technology Journal, 2016, Volume 34, Issue 12, Pages 2310-2317

Eleven simple span reinforced self-compacting concrete deep beams were tested under symmetrically two points top load to examine the influence of the transverse circular openings on their behavior. The variables investigated involve shear span to effective ratio a/d, opening sizes and locations and the amount of inclined reinforcement around the openings. All the beams had the same overall dimension, flexural reinforcement and concrete compressive strength. The test results showed that when the opening positioned at the center of the shear span significantly affects the behavior of the beams tested regardless of a/d ratio and size investigated. Also, it was found that when the opening of a large diameter positioned away from the load path either in thetopor bottom region of the beam reduces the cracking and ultimate load considerably. The inclined reinforcement around the opening was observed to be very efficient in improving the ultimate load capacities and deflection response.