Pultruded panels having a first longitudinal edge profile and a second longitudinal edge profile may be used to form a floor assembly mounted on a railway car underframe. The pultruded panels may also be used to form walkways, bridges, piers and other structures. A bead may be placed on at least one of the longitudinal edge profiles to form a gap between an adjacent pultruded panel. An adhesive may be placed within the gap to couple or bond adjacent pultruded panels with each other. Void spaces may be formed within the pultruded panel and filled with foam to provide improved resistance to heat transfer through the respective panel. Respective coverings may be placed on opposite ends of each panel to block access to the associated void spaces.