An Experimental and Analytical Study on the Behavior of Steel Fiber Reinforced Concrete Deep Beams with Openings

Abstract

In the first part of this research, an experimental study is conducted to investigate the effect of different types of steel fiber, web opening sizes and location as well as shear span to depth ratio on the behavior of deep beams. The aim of the experimental program is to investigate the effect of the tested parameters on strength, stiffness, cracking behavior and ductility of deep beams. Twelve specimens with dimensions of 1800mm×1100 mm ×100 mm were tested. Three types of steel fiber were used namely; end hooked, corrugated round, and corrugated segment. Also, two different types of web opening sizes (250×250mm, 350×350mm), two different opening locations and two different shear span-to-depth ratios (at 1/2 shear span, 1/3 shear span) were used. The second part of the research consisted of a numerical analysis using the computer aided software (ANSYS 14) to handle the nonlinear finite element analysis. Tests were conducted on the materials used in the tested beam specimens to ensure that the actual material mechanical properties were known for the numerical analysis. The experimental and numerical results were compared and contrasted. It can be concluded that using steel fiber in deep beams reduces cracking and improves its ductility as well as load capacity specially when using end hooked type. Beams with smaller opening size are more ductile in behavior than beams with larger openings. Placing the openings near the compression zone increases capacity at failure and reduces cracking compared to placing it at the tension zone near the supports. Loading at 1/3 shear span saves up to 30% of structural strength of the deep beam than loading at 1/2 shear span. The ultimate strength of reinforced concrete deep beam obtained by (ANSYS 14) is in good agreement with the experimental results.