July 26, 2024

A duo of engineering honors for CKC

Photo by Brian Miller [enlarge]

CKC was recognized for the structural design of this nine-story life science building, nearing completion at 222 Fifth Ave. N.

The Structural Engineers Association of Illinois (SEAOI) recently announced the winners of its 2024 Structural Engineering Awards which honor creative achievements in structural engineering via innovative structural designs.

The competition is open to projects from across the globe. Local shop Cary Kopczynski & Co. (CKC) won two awards.

The Bellevue-based structural engineering firm, which also has an office in Chicago, was awarded Best Project in the $50 million to $150 million category for The Lark, a new residential tower in Oakland, California. The firm also received a Merit Award in the same category for 222 Fifth Ave. N., a forthcoming biotech office building in downtown Seattle.

The Lark is set to open in Oakland's Uptown district next month. The 16-story building consists of twelve levels of light gauge steel residential framing over a four-level concrete parking podium. Concrete shear walls were selected for seismic resistance and are continuous full height.

Rendering courtesy of Cary Kopczynski & Co. [enlarge]

The Lark, a new residential tower in Chicago was named Best Project in the $50 million to $150 million category at SEAOI’s 2024 Structural Engineering Awards.

In early collaboration with the project's developer, CKC was able to eliminate the need for an exterior perimeter scaffold system by using a glazed curtain wall facade in lieu of punched windows. The Lark is one of the first buildings on the West Coast to use a curtain wall facade on a light gauge steel frame.

CKC told the DJC that the hybrid system of light gauge steel above and concrete below created a “cost effective yet high-quality structural system” by substantially reducing dead and seismic loads; eliminating all residential column conflicts since podium columns terminate at Level 4; and improving the parking efficiency since podium columns were located with no concern for the living units above.

Columns in the podium structure were located to optimize parking efficiency. At the residential levels, unit layouts were optimized without the need to negotiate columns, resulting in superior floor plans and uninterrupted views.

The Lark is in a region of high seismicity and is also located in a former tidal marsh associated with nearby Lake Merritt. These site factors complicated the seismic design challenge, and several structural systems were studied before the hybrid option was selected.

The Lark was designed by Solomon Cordwell and Buenz Architects. Washington company Holland Partner Group, which is based in Vancouver, is the developer and its construction arm, Holland Construction, is building the tower.

CKC's second winning project, 222 Fifth Avenue, is a speculative nine-story biotech office building designed to cater to Seattle's growing medical community. It includes eight levels of biotech office space over a ground floor lobby, retail and shared amenity space, and a two-story underground parking garage. The total project area is approximately 200,000 square feet.

Like The Lark, 222 Fifth Avenue employs, and was recognized by SEAOI, for its innovative structural system. The building is cast-in-place concrete throughout. Slabs are predominantly post-tensioned flat plates. The lateral force resisting system is shear walls combined with Ductile Moment Resisting Frames (DMRF's). High performance concrete was selected to enhance structural performance.

The main structural engineering challenge for this building was created by its design. Because of the need to create unhindered lab space, Gensler, the architect for the project, located elevator and stair cores along an alley side of the building. Since the cores were wrapped with shear walls and became the primary lateral force resisting system, a large torsional response was created under seismic load, requiring the addition of other lateral force resisting elements.

To resolve this, CKC integrated strategically located DMRF's into the layout by adding beams between already existing columns. This balanced the centers of seismic mass and rigidity, significantly improved seismic drift, reduced shear demand in the walls, and optimized rebar tonnage in the seismic system and foundations.

The engineer says this approach results in “a high level of seismic performance without complicating the building geometry or compromising its constructability.”

222 Fifth Avenue topped out in November 2023 and is close to completion. It is developed by LPC West and Intercontinental Real Estate. Lease Crutcher Lewis is the general contractor.

The full list of 2024 Structural Engineering Awards winners is at https://www.seaoi.org/Excellence-in-Structural-Engineering-Awards