Abstract: A demountable building structure that is readily assembled from a set of components is disclosed. The building structure includes a plurality of arc frame members spaced along a length of the building structure. Each of the arc frame members extends from a first foot portion to a peak, and back to a second foot portion. Each of the arc frame members includes a plurality of beams. Each of the beams includes two opposed flanges. Each of the flanges has two bifurcated ends. The ends define c-shaped rope chases with openings. The building structure further includes bases slidably mateable with the first and second foot portions, and elongate membranes having beaded longitudinal edges. The membranes are stretched between adjacent of the arc frame members. The longitudinal edges are within the rope chases. Spreaders extend between adjacent of the arc frame members for urging apart the arc frame members from each other and for maintaining the membranes in a stretched condition.