Massive Concrete Pour Anchors 41-Story Luxury Hotel-Residential Tower

Continuous Concrete Pour Sets Washington State Size Record

BELLEVUE, Wash.--()--Architects, engineers and construction workers building Bellevue’s Lincoln Square Expansion project will witness the state’s largest continuous concrete pour starting Feb. 28 at 3 a.m.

“The mat is designed to carry the weight of a 47-level structure and resist wind and seismic forces from the tower above. The design also provides a number of opportunities to implement creative and constructible solutions”

The continuous pour of 13,690 yards of concrete will last 24 hours and will form the structural base for the 41-story luxury hotel-residential tower.

“This massive mat of concrete and rebar is the foundation for what will become Bellevue’s premier luxury hotel-residential tower,” said Michael Chaplin, principal at Sclater Architects, the lead architect for the 1.5 million-square-foot, mixed-use Lincoln Square Expansion project. “In coming months, Bellevue residents will witness this tower and an adjacent office tower climb upward into the Bellevue skyline.”

Built atop six levels of underground parking, the tower will feature a designer hotel and luxury high-rise rental residences with unequalled views.

The concrete and rebar structure that will take shape Feb. 28 will anchor the 450-foot tower and play a critical structural role in supporting the cast-in-place concrete and steel structure. After removing more than 485,000 square feet of earth over the past year, workers recently installed more than 3 million pounds of rebar in the construction pit located at the corner of NE 4th Street and Bellevue Way.

“The mat is designed to carry the weight of a 47-level structure and resist wind and seismic forces from the tower above. The design also provides a number of opportunities to implement creative and constructible solutions,” said Mark Whiteley, P.E. S.E., Principal at CKC, the structural engineering firm working on the Lincoln Square Expansion. “The mat foundation utilizes high-strength steel reinforcing (80 ksi) to minimize congestion and reduce total steel tonnage.”

A self-consolidating concrete mix is specified for the bottom 18 inches of the foundation to ensure proper concrete consolidation where large concentrations of reinforcing bars occur. The remaining foundation will use a low-heat concrete mix to minimize temperature differential between the center of the mat and the exposed top surface.

“A tremendous amount of complex planning and coordination is required to execute a pour of this size,” said GLY’s Executive Vice President Ted Herb. “The north tower pour took hundreds of hours of teamwork between our employees, project partners, the City of Bellevue, and our subcontractors and suppliers to map out each and every detail.”

Saturday’s mat pour is the second on the site this year. Workers completed the first pour for the 450-foot office tower of the Lincoln Square expansion project on Jan. 31. More than 13,400 yards of concrete were pumped into the site over the course of 16 hours.

Quick Facts / North Tower Concrete Mat Pour

  • The concrete mat foundation provides stability and strength to the building and is 10 feet thick at its deepest point. Approximately 13,690 cubic yards of concrete and 1,470 tons of high-strength reinforcing steel go into the slab.
  • The 76,000-ton building above the foundation is supported by columns constructed of high-strength concrete with a capacity of 14,000 pounds per square inch. These columns are in turn supported by the mat foundation, creating pressures of 12,000 pounds per square foot on the underlying soil.
  • The size of a mat foundation is determined by the size and weight of the building, the soil bearing capacity, and the forces on the building during an earthquake or wind storm.
  • The temperature at the center of the mat will reach 150 degrees Fahrenheit 24 hours after the pour as a result of a chemical process called cement hydration, the reaction of water to other components of the concrete mixture. The process is what ultimately strengthens the concrete. The slab temperature typically cools down over the course of a week after the pour. Three thermometers placed respectively at the bottom, middle and top of the mat are used to monitor the temperature.
  • Eighty-one trucks will run continuously between the site and 5 local concrete plants starting at 3:00 a.m. Seven concrete pumps will be used at the job site.

NOTE: Reporters interested in photographing the mat pour are asked to use the location adjacent to the site described below.

Reporters interested in interviewing the project team members should contact the individuals identified at the bottom of this news release.

About The Bellevue Collection

Located in the heart of Bellevue, Washington, The Bellevue Collection, owned by Kemper Development Company, includes Bellevue Square, a super-regional upscale shopping center, Bellevue Place, a mixed-use property featuring the Hyatt Regency Bellevue and small boutiques, and Lincoln Square, anchored by the Lincoln Square Cinemas, restaurants, home furnishing stores and The Westin Bellevue hotel. With a distinctive collection of 250 of the finest shops, 30 sit-down restaurants, a 16-screen premier cinema, 1,100 luxury hotel rooms and 10,000 free retail parking spaces, all in one location, The Bellevue Collection is a shopping, dining and nightlife and entertainment experience unlike any other in the region. It is located on Bellevue Way between NE 4th and NE 10th Streets in downtown Bellevue, just across Lake Washington from Seattle.

About Sclater Architects & HKS, Inc.

The award-winning team at Sclater Architects employs a mindful approach to design, creating spaces that deepen the connection between clients and their customers and people to their spaces. Working with Sclater Architects as an associate firm on the design of the north tower is HKS, Inc., a Dallas-based architecture firm. The team has designed successful buildings by paying close attention to the needs of their clients and their communities. Through a collaborative design process, Sclater Architects and HKS bring together the best resources for each individual project. Since its inception, Sclater Architects and its principals have designed a variety of projects across the country, including much of the nation’s early retail development. Today, the firm offers an expanded list of project types, including mixed-use, office, hotel, multi-family housing, retail, education and tenant improvements. For more information, visit For more information about HKS, visit

About Cary Kopczynski & Company

Cary Kopczynski & Company is an award-winning structural engineering firm with offices in Bellevue, San Francisco, and Chicago. CKC designs major urban buildings throughout the United States and beyond. The firm’s current projects include high-rise towers, mixed-use projects, hotels, and parking structures in many states. CKC’s passion for innovation and new technology, combined with extensive experience, consistently inspires cutting-edge structural designs that lead the industry. The firm has won over 45 regional and national awards and has twice been selected as a Best Structural Engineering Firm to Work For by ZweigWhite. For more information, visit

About GLY

GLY Construction, Inc. is a Puget Sound general contractor offering excellent preconstruction services, principal-led teams and award-winning quality in a variety of project sectors. GLY is committed to pursuing industry innovations, notably in Lean, sustainable building practices and Integrated Project Delivery, as well as community involvement through outreach and education. As involved members of the Bellevue community for nearly four decades, GLY has long been committed to the health and vitality of its civic institutions and businesses. The company is very proud of their contributions to the growth of the city, thanks to valued clients like Kemper Development Company. Visit

NOTE TO REPORTERS: Interested in Getting Visuals to Accompany Story?

Optimal media viewing area during the pour:

The optimal viewing area for media covering this story is on the sidewalk in front of the Cheesecake Factory on Bellevue Way (on the Bellevue Square side of the street). Media will be able to see truck, pump and worker activity.

PLEASE NOTE: Direct access to the construction site directly is not possible from a safety standpoint.


Media Inquiries:
Sclater Architects/The Keller Group
Daven Rosener, 253-307-5402
Cary Kopczynski & Company
Mari Wada, 425-455-2144, x105
Melanie Cochrun, 425-519-4338

Release Summary

Architects, engineers and construction workers building Bellevue’s Lincoln Square Expansion will witness Washington state's largest continuous concrete pour – 24 hours and 13,690 yards of concrete.