Two impressive digester tanks are being built by Bradbury Stamm Construction on the Paseo Real Wastewater Treatment Plant in Santa Fe, New Mexico. Each tank has an inside diameter of 55‘, with 18“ thick walls that are 34‘ tall. The contractor chose to place each tank in just two pours using one set of GRV forms. PERI’s GRV formwork has vertical GT24 girders that are backed by GRV walers, which utilize large pins and adjustment bolts that make it possible to conform to the tanks inner and outer diameters. These walers link together to form complete rings that are equally effective in tension (outer ring) or compression (inner ring), which makes it possible to pour these walls with ZERO formwork ties! The final adjustments to ring size are made possible by the adjustable GSRV waler, which also serves as stripping relief after the walls are poured.
The contractor will form the inside of the tank to full height (34‘ tall), allowing them to place all of their rebar at once. The outside form is 20‘ tall and will be utilized twice per tank: Once to pour the full circumference up to the only construction joint 20‘ off of the slab. And then the second lift, where these forms will be set and plumbed from CB climbing brackets, which provide an 8‘ elevated work platform around the outside. The forms will then be cycled over to tank 2.
Other tank forming methods require ties and more construction joints (usually with vertical construction joints), which means more labor to cycle the equipment, tie patching and waterproofing materials and labor, additional waterstop material and installation costs. The reduction in construction joints and elimination of formwork ties really decreases the probability of future warranty work.
Bradbury Stamm Construction