Abstract: A modular ground deployable membrane supporting building structure and arched truss member therefor. The building structure incorporates a plurality of truss members supportable vertically in side-by-side arrangement within a ground anchor connectable at each end of each truss member. Each truss member is comprised of a plurality of frame sections each connectable in aligned abutting end-to-end relation. Each frame section is comprised of inner and outer channel members having a unique U-shaped cross section facilitating cross member connection to secure a spaced parallel relation of the channel members, flexible membrane retention and improved strength and reduced deployment time. An improved membrane tensioning arrangement and ground anchor structure facilitating pivotal deployment of each assembled truss member are also provided.