Rainier Square Tower

The Rainier Square Tower is a Contemporary skyscraper designed between 2006 and 2014 by NBBJ, and built between 2017 and 2020, for a reported $600 million dollars, in Seattle, WA.

Its precise street address is 401 Union St, Seattle, WA. You can also find it on the map here.

The Rainier Square Tower has received multiple architecture awards for its architectural design since 2020. The following is a list of such prizes and awards:

• Construction Award by the Council on Tall Buildings in 2021
• Excellence in Structural Engineering Award in 2021
• Best Tall Mixed-Use Building - CTB in 2022
• OCEA Award by the American Society of Civil Engineers in 2022
• IDEAS2 Presidential Award in 2022
• Gold Engineering Excellence Award in 2022
• NAIOPWA Night of the Stars Awards in 2023

NBBJ was the architecture firm in charge of the architectural design.

That being said, architecture is a complex discipline involving many professionals from different fields, without whom this building would have not been possible. We will surely be leaving out a lot of names here, but here is a list of the people we do know also played their part in making the Rainier Square Tower a reality:

• Magnusson Klemencic Associates in charge of Structural Engineering
• Lease Crutcher Lewis as the Main Contractor
• Otis Elevator Company as the company in charge of the elevators system
• Wright Runstad as the Main Developer
• Gustafson Guthrie Nichol in charge of Landscape Architecture
• NBBJ in charge of Interior Design

The Rainier Square Tower can be categorized as a Contemporary building.

The Rainier Square Tower uses a framed tube-in-tube structure , with a concrete core and steel columns and poured concrete over metal decking slabs.

A framed tube-in-tube structure uses a central core, known as inner tube, which usually holds stairs, lifts and installations, and a perimeter of columns around it, which form the exterior tube. The interior tube is tipically more massive (often made of reinforced concrete), and the exterior tube is "lighter" (made of steel or concrete columns). Both tubes are conencted via horizontal elements which make up the floors and also transmit any horizontal froces from the facade to the core.

The facade employs a non-load bearing curtain wall system. This means the curtain wall modules are anchored to the building's structural frame at the edges of the floor slabs. The perimeter columns are set back slightly from the facade, allowing them to remain independent of the curtain wall system.

This configuration enables a completely free design of the curtain wall, unencumbered by structural elements, thus providing greater flexibility in aesthetic choices and maximizing the visual impact of the exterior.

In the structural construction, the traditional concrete core commonly used in high-rise buildings was replaced with a sandwich core made of steel and concrete, known as "SpeedCore."

This core, the first of its kind ever built in a high-rise,  is built using modular steel units that are transported by a crane, stacked like building blocks, welded together, and then filled with concrete.

With this innovative approach, the surrounding steel structure was no longer constrained by the core, allowing the team to save nine months in construction time.

From an aesthetic point of view, the facade features blue-tinted glass decorated with vertical aluminum elements.

On the east side the facade slides like a gentle stepped cascade, forcing the glass to take an angled position that varies from floor to floor and which required 140 uniquely 3D-printed nodes.