FLEXURAL BEHAVIOR OF CONCRETE BEAMS REINFORCED WITH STEEL PLATES AS MAIN REINFORCEMENT

Abstract

ABSTRACT In the past few years, new techniques have emerged using steel plates instead of traditional reinforcement in reinforcing concrete beams to resist flexural stresses. This study deals with the use of a new technique for reinforced concrete beams using plates instead of traditional steel bars with different thicknesses while maintaining a constant cross-sectional area. The experimental work consists of two groups, each group contains (5) specimens, which are (3) specimen with a plate thickness of (4,5,6) mm placed vertically and a specimen with a thickness of (6 mm) plate placed horizontally. In addition to the reference specimen with a diameter of (16 mm) for the first group and a diameter of (20 mm) for the second group noting that the steel plate that used is from checker type and keeping the equivalent area for conventional steel bar constant for all specimens. The dimensions of the specimen for all specimens are (2100 mm) in length, (350 mm) in height, and (250 mm) in width. These specimens were tested under four points bending. The results showed that as the thickness of the steel plate increases, the samples will have greater resistance until more deflection is produced. In addition, there is a reduction in the crack load, yield load, and ultimate load when replacing reinforcing bars with steel plate. In which, a reduction in crack load by about (11.10%, 15.50%, 22.20%, and 33.30%) for plate thicknesses of (4,5,6) mm vertical and (6 mm) horizontal, respectively, compared to reference. The yielding load is reduced by about (42%, 53%, 60%, and 51%) for (4,5,6) mm vertical and (6 mm) horizontal plate ii models, respectively, compared to the reference specimen. In addition, ultimate load was reduced by (36%, 40%, 33%, and 40%) for (4,5,6) mm vertical and (6 mm) horizontal plate models, respectively, compared to the reference specimen. Moreover, the deflection at yield load increased by (110%, 108%, 98%, and 55%) for vertical plate thicknesses of (4,5,6) mm and horizontal plate thickness of (6mm), respectively, compared to the reference specimen. In addition, the deflection at ultimate load was reduced by about (29.00%, 27.31%, 27.18%, and 23.00%) for vertical plate thicknesses of (4,5,6) mm and horizontal (6 mm), respectively, compared to the reference specimen. In addition, the yielding load decreased by (42%, 53%, 60%, and 51%) for plate thicknesses of (4,5,6) mm vertical and (6mm) horizontal, respectively when decrease the cross-sectional area of steel by using equivalent are from (20mm) to (16mm) of reference specimen. Moreover, as the thickness of the steel plate increases, the measured crack load, ultimate load and yield load are increased. Finally, by increasing the cross-sectional areas of the steel from (16mm) to (20mm) the crack load measured increases by (33.33%) (for reference specimens), and increases by (37.50%, 18.42%, and 14.28%) for (4, 5, and 6 mm) plate thickness. The horizontal direction of steel plate samples of (6mm) thickness increase about (50.00%) when increasing the cross-sectional area