Pima County Downtown Courts Complex – Concrete
· Total Project Cubic Yards: 17,794
· Mat Foundation: 7,828 CY’s / 2,390 MHRS / Averaged 420 Cubic Yards per Hour for the Pour
· Total Project Man-hours: 24,196
· Slabs On Metal Decks: 234,986 SF
· Basement Walls; 24,007 SF (Single Side)
Sundt’s own crews performed all of the concrete work to create the foundation for the new Pima County Downtown Courts Complex in Tucson. It took 7,500 cubic yards of concrete, placed in two overnight operations, to create the 24,000-square-foot foundation.
Why so much concrete for a seven-story building? The site’s soil is exceptionally sandy, which made it difficult (and costly) to construct a traditional foundation formed around caissons drilled deep into the ground. Instead, the team opted for a “compensating mat slab” foundation 25 feet below grade to support the weight of the building. Spanning just over an acre, the five-foot-thick slab necessitated two of the largest concrete placements in Tucson’s history.
It took two batch plants – one on Tucson’s far northwest side and one in the nearby community of Vail – to make and supply enough concrete for the two placements. By performing the operations at night, Sundt was able to minimize potential complications stemming from traffic delays and heat.