The Use of Space Swimmer Bars as Shear Reinforcement in Reinforced Concrete Beams

Abstract

Abstract--The sudden nature of shear failure in reinforced concrete beams is undesirable and requires special attention. This undesirable mode of failure pushes the design engineers to use higher factor of safety against the shear forces. Several alternatives to the traditional stirrups were introduced in the past including the concept of the swimmer bars. This study focuses on special kind of swimmer bars. The new swimmer bars system used in this study is called space swimmer bars system which requires no welding to be assembled. The space swimmer bars concept is new and effective in improving the shear performance of reinforced concrete beams. The results of this study will be compared with the traditional stirrups, as well as the welded swimmer bars. The space swimmer bar is basically a reinforcing bar bent several times in the three dimensions forming special configuration along with its coupling swimmer bar. This configuration makes the shear reinforcement system act as plane-crack interceptor rather than linear bar-crack interceptor. This new system is not only effective in taking care of the shear forces, but also it is economical compared to the traditional stirrups and the welded swimmer bars. There is no available data to show the performance of the welded swimmer in the long run, but this new type of swimmer bars system requires no welds. In addition, welding shear reinforcement bars does not seem to be desirable in the construction engineering practice. Several beams will be tested. One group of beams are reinforced with standard traditional stirrups as shear reinforcement and they are used as control samples. The second group of beams used welded swimmer bars as shear reinforcement system. The third group of beams used the new space swimmer bars as alternative to the existing shear reinforcement systems in reinforced concrete beams. The results of the three groups of beams will be presented. Flexural cracks as well as shear cracks will be monitored with the increase in the applied load. The deflection at the mid-span of the beam will also be monitored as the applied load is gradually increased.Keyword-Space swimmer bar, Deflection, Shear, Crack, Stirrup I. INTRODUCTION The main objective of the design of reinforced concrete beams is safety. The sudden failure mode requires higher factor of safety. The design engineer has to make sure that the mode of failure is acceptable and gives enough warning before failure. The shear failure is not one of the desirable mode of failures and should be avoided. Reinforced concrete beams are one of the common structural elements that carry transversal loads mainly by flexure and shear. The common design approach is to design the beam for flexure then design the beam for shear. The available design codes emphasizes on the ductile flexural failure by reducing the amount of steel reinforcement in the tension area, in order to make sure that the longitudinal tension bars yield first. While the design for shear focuses on providing enough shear resistance exceeding the ...

Investigating the Tansitional State Between Rectangular Plates and Shallow Shells

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Punching shear resistance of strengthened reinforced concrete interior slab–column connections using ultra-high-performance strain-hardening cementitious composite material

“…Over years, various enhancement/strengthening techniques have been developed in order to improve the punching shear resistance for RC flat slabs. These techniques include using traditional shear reinforcement in the form of single- and multiple-leg stirrups, swimmer shear bars, bent-up bars, inclined stirrups, inclined shear band reinforcement, post-installed reinforcement, steel links, external steel plates with steel anchor shear studs, steel shear head, shear stud with single or double head, helical reinforcement, external carbon fiber reinforced polymer (CFRP)/glass fiber reinforced polymer (GFRP) stirrups/rods or externally bonded (EB) CFRP/GFRP laminates/strips, and mesh reinforcement (ACI 318-14, 2014; Al-Nasra et al, 2013; Bartolac et al, 2015; Binici and Bayrak, 2003, 2005a, 2005b; Chen and Li, 2005; Corely and Hawkins, 1968; Durucan and Anil, 2015; Elbakry and Allam, 2015; Esfahani et al, 2009; Faria et al, 2014; Ferreira et al, 2014; Harajli and Soudki, 2003; Kang and Wallace, 2005; Khaleel et al, 2013; Meisami et al, 2013; Najmi and Marahlah, 2015; Oliveira et al, 2000; Park et al, 2007, 2012; Pilakoutas and Li, 2003; Ruiz et al, 2010; Sissakis and Sheikh, 2007; Soudki et al, 2012; Tassinari et al, 2011). Providing internal short steel/fabric fibers into the entire slab or a partial area near the slab–column connection is another technique used for enhancing the behavior of the cracked tension region as well as the undamaged concrete in the compression zone (Cheng and Parra-Montesinos, 2010; Choi et al, 2007, 2012; El-Ghandour et al, 2003; Harajli et al, 1995; Hassan et al, 2015; Ju et al, 2015; Mandl, 2008; Tan and Paramasivam, 1994).…”