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 .