Flexural Behaviour of Concrete Beams Reinforced With Steel Plates

Steel plates have the potential to be used as ductile reinforcement for concrete beams as a preferable alternative to steel bars. However, their potential was not addressed adequately in the previous studies, particularly in the beams tested under flexural loading. Only a few published studies investigated plate reinforced concrete beams and most of them used steel bars and steel plates together in the same cross-sections of beams. Moreover, beams reinforced with horizontally oriented steel plates were not investigated in the previous studies. The present study investigates the flexural behaviour and performance of concrete beams reinforced with chequer steel plates as the main reinforcement; the steel plates are oriented either horizontally or vertically. In order to achieve the objectives of this research study, an experimental study was conducted on plate reinforced concrete beams. Five full-scale beams having the dimensions of 200 mm width, 300 mm height, and 4000 mm length were cast and tested under four-point bending at the structural laboratories of the University of Wollongong, Australia. One beam served as a reference beam reinforced with steel bars. Two beams were reinforced with horizontal steel plates, one had bolts as anchors while the other had angles. Another set of two beams were reinforced with a pair of vertical plates each, one using steel threads as anchors while the other using angles. Details of the compression reinforcement and stirrups were the same for all beams. Each beam was tested to fail in flexure to determine the stiffness, ultimate strength, ductility, behaviour, toughness, crack propagation, and failure mode. The main test results indicated that the chequer steel plate reinforcement improves the properties of the beams. Compared to the traditional referenced concrete beam, the beams reinforced with a horizontal plate exhibited much greater ductility. The beams reinforced with vertical plates had poor ductility, with a drop in the load at the ultimate limit state; however, they experienced high load carrying capacities. An experimental study on the bond behaviour of chequer steel plate reinforcement in concrete members was also conducted. The effects of lozenges of the chequer steel plate, the use of steel bolts, and the thickness of the concrete cover on the bond behaviour were investigated. The experimental program included five beam pullout specimens. Stirrups with 80 mm centre–to-centre spacing were used as confinement for all specimens. The main test results indicated that the existence of lozenges of steel plate and a steel bolt considerably increased the bond strength of specimens. An analytical study was also presented for concrete beams reinforced with traditional or steel plate reinforcement. Two different analytical techniques, including equivalent rectangular stress-block method and numerical integration method, were used in the analysis of reinforced concrete beams. Three stress-strain models were implemented to represent the behaviour of concrete in numerical integration method. For both analytical methods, the analytical results exhibited a good agreement with the experimental results. All the steel plate reinforced beams were able to reach ultimate test loads within 10% off the theoretically predicted values. A parametric study was conducted to investigate the effects of different parameters, including using of various thicknesses and yield strengths of steel plates that have not been studied on plate reinforced beams in the experimental work. Finally, the experimental findings of this study showed that the concept of using steel plates to reinforce concrete beams is available and an efficient technique