May 24, 2023

500 ready-mix truck loads used in massive Bellevue concrete pour

Photos courtesy of Mortenson [enlarge]

Crews worked for 12 hours to place 5,000 cubic yards of concrete.

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The mat has over 1,230 tons of rebar in it.

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The mat is eight levels below grade.

The first in a fleet of ready-mix trucks began rolling onto the Four106 office tower jobsite at 3 a.m. Saturday in downtown Bellevue. Twelve hours later, those trucks had delivered about 500 loads of concrete for the building's massive mat slab foundation.

The hole at 350 106th Ave. N.E. will eventually become a 485,000-square-foot office tower of 21 stories. To support that, Mortenson created the mat slab at the bottom where eight below-grade parking levels will rise to the surface. Assuming all of those trucks from Stoneway Concrete were full, that's about 5,000 cubic yards of concrete for the base. To fortify the slab, crews installed over 1,230 tons of rebar.

Concrete came from two separate Stoneway plants.

Since the weather was relatively hot last weekend, Mortenson worked with Stoneway to keep the concrete cool by applying over 31,000 gallons of liquid nitrogen at the plants before delivery. Concrete was moved to the pit by four pumper trucks provided by Brundage-Bone Concrete Pumping, each fed by two ready-mix trucks.

Mortenson said the pour marked a crucial step in the construction of the speculative office tower, which is slated to open in 2025. A news release from Mortenson said the tower will have flexible floor plates, customizable layouts, collaboration zones and first-class features.

Four106 is being developed by Patrinely Group in partnership with Dune Real Estate Partners. The DJC reported in July 2022 that Patrinely and Dune bought the project from Fana Group in January 2022 for over $95 million.

“After a tremendous effort by the Mortenson team in digging out the foundation, we're excited to have reached this milestone and to be building back up towards the sky,” said Matt Chamberlain, Patrinely's executive vice president responsible for the western U.S., in the news release.

The design team is led by architect CollinsWoerman and structural engineer DCI. The Broderick Group is leasing Four106 on behalf of Patrinely and Dune. Erin Wagner is Mortenson's project manager.

Patrinely is a national real estate investment, development, leasing and management firm focused on large-scale Class A office, multifamily, industrial and data center properties in major markets. Dune is a New York City-based real estate investment firm focused on high yielding real estate equity investments for pension funds, sovereign wealth funds, endowments, large institutions and high-net-worth individuals.