Flexural Behavior of New Hybrid Profiled Steel-FRP T-Beams Filled with Concrete: Development and Validation

Abstract

This study presents an innovative hybrid profiled steel- and fiber-reinforced polymer (FRP) reinforced concrete (HPSFRC) structural system that primarily consists of thin semiclosed T-shaped cold-formed steel sheeting that is externally enclosed with an FRP sheet and filled with concrete. The experimental study was conducted in two interdependent parts: a development study and a validation study. In the development study, six specimens were tested to determine the best interlocking technique between the concrete flange and the other components of the cross section. In addition, two specimens were examined to define the shear strength of the steel-concrete composite profiled system. The validation study presented the flexural behaviors of HPSFRC T-beams with different reinforcement configurations. The test results of the HPSFRC beams were assessed in terms of the behavior of a conventional reinforced concrete T-beam and a composite profiled T-beam. The HPSFRC T-beams achieved a ductility comparable to that of a composite profiled beam but exhibited a higher flexural strength. The flexural behaviors of the HPSFRC beams can be controlled using additional longitudinal reinforcement at the beam tension side. The beam with additional steel bars exhibited ductile behavior with a stable increase in the beam resistance to the applied load; however, the addition of FRP layers enhanced the flexural capacity of the beam and greatly controlled the deformability of the beam after steel yielding, resulting in the lowest measured residual deflection.