The Extent Effect of Concrete Material on the Flexural Performance of Solid and Hollow Double Skin Tubular Beam

Double skin tubular beams (DSTB) were introduced in the field of civil engineering to be used in different structural members, such as beams and columns. However, several advantages were provided upon the utilization of DSTB, including the reduced weight and high strength. On the other hand, this study introduces an effective solution for improving the beam’s ductility upon the utilization of large rupture strain (LRS) FRP sheets; one wrapped along the beam’s cross section, and the other lies at the bottom tensile side of the beam. This study examines the extent effect of concrete material on the flexural behavior of DSTB in two main directions. The first pillar was to simulate the beams with an inner hollow and solid concrete, and the other pillar was to simulate the effect of concrete compressive strength (20 MPa, 35 MPa, and 50 MPa). The study outcomes were accomplished using the nonlinear finite element analysis (NLFEA) methodology, where results were introduced to represent design guidelines for designing and rehabilitation of structural components. The conclusions of the study cover wide structural performance indicators, including weight, cost, strength, and ductility.