A new hybrid floor system comprising embedded glass fiber reinforced polymer (GFRP) I-beams and GFRP stay-in-place (SIP) structural forms as bottom reinforcement and top GFRP rebar is developed for rapid floor construction. The SIP forms are flat plates with T-up longitudinal ribs spanning the 1200 mm spacing between the I-beams and supported on the bottom flanges of the I-beams. In this study, a robust three-dimensional finite element (FE) model is developed and is capable of simulating the concrete nonlinear behavior in tension and compression, composite failure of the FRP systems, and various contact types; including between SIP form and concrete; SIP form and I-beams; and the I-beams and concrete. Two independent flexural test programs, including tests by the authors and tests reported in literature, were used to calibrate the model. Following calibration, the FE model will be used in an extensive parametric study to investigate different parameters impacting the new floor system.