The New Sumner High School

How do you ensure a large building in mushy soils will be around for the next 100 years? You set its foundation on over 100 piles that are exactly 100 feet deep!

The new Sumner High School (Sumner-Bonney Lake School District) currently under construction, will be one of the Sumner Valley's tallest and heaviest structures to date. Under HAINLINE’s project management, the design team (Migizi Group, Inc. , PCS Structural Solutions, BLRB Architects) conducted extensive analysis and seismic mode

ling given the known condition of the soils and the chance of liquefaction in a major event. The team concluded that the best way to create a stable foundation system was to set thick grade beams atop piles drilled deep enough to reach resistive soil.

Specifically for the new Sumner High School, that meant bringing in Malcolm Drilling to use their specialized auger drill rig to install 106 piles 100 feet deep. They did this by first drilling the holes, filling them up with grout while they extracted the augur, and then craning the epoxy rebar cage which sunk down into the hole like a dipstick.

In addition to the piling, the project has excavated 5,600 cubic yards of earth so far and imported 7,560 tons of gravel.

Check out the drone footage of the piling work! Incidentally, the drone footage was taken by one of the District's marketing staffers.

The new High School is slated to be complete by January 2023.