Demolition on Barney Allis Plaza is well underway! If you’ve driven or walked by the site over the last few months, you may have noticed the construction barriers and increased activity on the plaza’s surface. And, the view has gotten a little bit clearer.
Removal of the pergolas, existing structures, and surface vegetation is complete, as well as demolition and removal of concrete and other support materials from the plaza level. Approximately 117 tons of metals, 8,060 tons of concrete or rubble, and 20 tons of greenery/vegetation have been taken down and recycled or reused to date.
The plaza’s original surface was built on top of the parking garage, up a flight of stairs above the surrounding sidewalk and streets. When completed, the entire reconstructed green space, playground, dog park, event plaza and pavilion will be street level. The park will be more accessible from all sides and every corner.
With surface demolition nearing completion, crews have shifted gears to work in the below-ground garage level.
One of the first steps in prepping for reconstruction of the parking garage is the installation of tiebacks through existing perimeter walls. Tiebacks are a system of steel bars or cables bunched together acting as a tendon connecting two structures. In this case, tiebacks secure the structural stability of the garage by connecting the existing perimeter walls to the bedrock beyond. This system helps provide additional structural support for the walls and adjacent roadways.
Graphic of a tieback system
Essentially, a “tieback” ties the existing walls back to bedrock.
Tiebacks are anchored in the walls through a process of drilling holes (up to 55 feet!), and then installing and grouting steel tendons.
This is how tiebacks work:
- Steel tendons are drilled through the existing perimeter wall, through soil behind the wall and into bedrock at various angles.
- When the steel tendon is installed through the hole, grout is pumped in the space to anchor it to the bedrock.
- One end of the steel tendon is secured to the wall, and the other end is anchored to a stable structure (bedrock).
This resistance enables structures to withstand higher forces and pressures, ensuring their stability and longevity.
When tieback installation is complete, the garage walls will be stable for the next phases of construction. This includes demolition of the entire existing garage, from the top down starting on the south end.
Tieback system photo gallery
