The main idea of castellated steel beams is to reduce their weight by creating void space (web holes) in the main beam body. This structure tends to exhibit superior properties such as advanced strength, lightweight, and cost-saving compared to the amount of steel used compared with reference beam without web holes. This study is devoted to investigating the structural behavior of double-channel cast steel beams. In this project, two pieces of a rolled hot steel channel were connected to form a new section used in the testing program. Five beams of different sections were manufactured and tested using the same length and all testing parameters conditions with only a difference in the number of openings and distance (e) between each hole to study the behavior of section to different bearing loads and deformation. Two loading points were placed on a third of the length of the castellated steel beam. This study showed that when the web holes are few, the total bearing strength decreases. As the number of web holes increased to a specific limit, the bearing strength continued to rise, and if openings exceeded a specific limit, the bearing force decreased. The rate of increase to the bearing force was found between 17.7-40.0%. Lastly, as per beam deformation, the deformation value decreased as the number of openings increased, which was taken at the maximum load of the reference beam.

The aim of this research is to investigate whether construction rubbles may be utilized as coarse aggregates in concrete. Experimentally, the slump, unit weight, compressive, tensile, and flexural strength tests were applied on concrete samples with varying percentages of recycled coarse aggregate (RCA) and compared with reference concrete produced with natural coarse aggregate. This research conducted 96 concrete samples with RCA replacement percentages of 0, 35, 65, and 100%, respectively. The control mixture produced with natural aggregate showed better results than the mixtures containing recycled aggregate; thus, compressive, tensile, and flexural strengths reduced as the amount of the recycled aggregate increased. Using 100% RCA, the compressive, tensile, and flexural strength reduction reached up to 64, 29, and 38%, respectively.

This study investigates the analytical approach of web reinforcement techniques, including high-strength concrete and laced reinforcement, to enrich improvement for the structural behavior of these beams. The analysis compares an unmodified cellular beam (LB1) with a web-reinforced beam (LB2), including the improvements in load-carrying capacity. The study considers the effects of reinforcement on critical design limit states, such as flexural strength, Vierendeel bending, web post-buckling, and shear resistance. The outcomes reveal significant enhancements in LB2’s structural behavior, with over a 100% increase in flexural strength and local axial force capacity and a 165% increase in web post-buckling strength. This research validates the effectiveness of web reinforcement techniques in concentrating on the limitations of cellular beams and maximizing their potential in structural applications.