You’ve gotta go down, to go up! No, it’s not a riddle, it’s the reality of rebuilding the Barney Allis Plaza. For the last few months construction crews have made major progress on the working down part of the plan, first with tiebacks to secure the existing walls, then with demolition of the old underground garage starting on the south end. Soon, work to build foundations for the new garage begins, and only half of the plaza top currently remains.
Establishing a new ground level is not as easy as digging out a bunch of construction debris. There’s a multi-step process involved. Crews will start earthwork by testing existing substrates and removing any unsuitable materials. Then, they fill holes left by original foundations and level the site. Finally, once the site is level, they will create a “building pad” by placing fill material (mostly crushed stone) in small increments called “lifts,” until they get to the right elevation to start the remainder of construction activities.
This process, called grading, allows for proper drainage and establishes a solid foundation for the project. In addition to special equipment, the process requires testing and inspections before completion. All of this will take place 35 feet below street level.
Once grading is complete, the fun really begins! Crews will start installing approximately 245 piers ranging from 42-72 inches in diameter that will anchor the garage and plaza’s new structure. The piers, which are made of concrete and reinforcing rebar, must be inserted and set with concrete the same day they are drilled.
After the piers are installed and grade beams are placed on top of them, construction on walls, slabs, ramps and decks will begin, marking the start of vertical construction – the go up part of the process! And speaking of up, keep your eyes toward the sky this spring. You won’t be able to miss our huge tower crane – which requires its own crane to install! – going in as crews prepare to complete this work.
Tieback system photo gallery
