Graduation Semester and Year




Document Type


Degree Name

Master of Engineering in Civil Engineering


Civil Engineering

First Advisor

Raad Azzawi


This study investigates the behavior of encased steel composite beams in straight and preflex beams, constructed and tested at Civil Engineering Laboratory Building (CELB). Upwards camber is provided in the steel sections in steel angles and HSS tube in the composite beam encased in Steel fibers reinforced concrete (SFRC). Experimental procedure has been performed to study the flexural behavior of composite steel joists encased in SFRC. Compressive strength, tensile strength and modulus of rupture are computed. The physical properties of steel fiber reinforced concrete are calculated through testing at the UTA Civil Engineering Laboratory Building. Eighteen cylindrical (4”x8”) specimens, eighteen beams encased with Double angle (6”x6”x20”), eighteen beams encased with HSS steel beams (6”x6”x20”) were prepared and tested after 28 days of curing. The specimens were tested for their compressive strength, tensile strength, and modulus of rupture. The results showed that compressive strength increased by 45% with adding steel fibers of 1% by volume in concrete. Also, addition of 1% steel fibers by volume increases the tensile strength by 33% as compared to 0% steel fibers by volume. The experimental results showed that, cambering of double angles in concrete beam increases the ultimate load capacity by 10% while midspan deflection reduces by 25% relative to straight section in concrete beam. The study investigates flexural behavior HSS and double angle encased concrete beams, while results shows approximately similar performance for both type of beams. Use of steel fibers reinforced concrete is also an advantage to increase the flexural capacity of beam and to reduction in midspan. Adding 1% volume fraction of steel fibers to increases the ultimate load capacity by 30% and reduces the midspan deflection by 41% comparative to concrete without steel fibers. This study shows that, there is significant improvement in the flexural capacity of beam with the provision of cambering and addition of steel fibers. Preflex Encased steel Joist Composite Beams are innovative structural members that provides more strength to structures with long spans like long span bridges, because it requires girders of large flexural capacity.


SFRC, Composite beams, Steel joists


Civil and Environmental Engineering | Civil Engineering | Engineering


Degree granted by The University of Texas at Arlington