A method for fabricating a space frame structure, such as a dome, for covering an open space, with the space frame structure being assembled from beam members, which intersect at rigid mode joints. The beam members and other structural components used in the skeleton of the space frame are made from pre-cast concrete, which has not been subjected to pre-tensioning and the rigid node joints are formed in situ, for example, by casting concrete joints incorporating the ends of the beam members. The loads imposed by the weight of the beam members on the beams and the node joints effectively simulate pre-stressing of the components which act within the assembled structure as pre-stressed concrete.