A novel build-first-then-excavate technique was used in the construction of the new dome-roofed civic auditorium for the city of Albuquerque, New Mexico. The concrete for the 218 foot diameter thin shell dome roof was poured on a natural mound of earth as a means of saving costly formwork and shoring normally required for this type of construction. The estimated savings on the $1 million project was about $50,000. The first step was to excavate a deep trench clear around the mound. The trench was then backfilled and the mound was shaped and surfaced to receive the concrete for the dome. The shell concrete was placed starting from the outer circumference, with the first of four concentric pours being chuted directly from ready mix trucks. After the shell concrete had set, the heavily reinforced ring girder was restressed with high strength wire prestressed to 140,000 psi. According to the designers, the function of the prestressed ring girder is to place the entire structure in equilibrium. After completing the stressed collar by filling the channel with concrete, shovels and bulldozers began the man-sized job of removing some 120,000 cubic yards of earth beneath the shell. The remaining portions of the structure were completed by conventional methods.