LONDON'S MOORGATE EXCHANGE MAXIMIZES RENTABLE SPACE WITH EXPOSED STEEL HSS

For the Moorgate Exchange 12-story office building constructed on the site of London’s old telephone exchange, maximizing the rentable commercial space was a key design requirement for architects HKR Architects and Pringle Brandon Perkins+Will.

Photo courtesy of Tata Steel

Supporting slender perimeter columns, a smooth finish, and attractive aesthetics, concrete-filled exposed steel hollow structural sections were specified by Ramboll for London’s 12-story Moorgate Exchange.

“For this project, it was important that the perimeter columns were slender to complement the facade when viewed from the inside,” explains Alex Baalham, MEng MIStructE CEng, director, Ramboll, London.

As a premium real estate development, internal aesthetics are a high priority, necessitating a smooth, unobtrusive finish on the columns, which were visible on each floor.

Given these directives, exposed steel HSS were an ideal choice.

“Concrete-filled HSS columns were specified primarily for their slenderness, the high-quality of paint finish that could be achieved—as intumescent was not required—and the increased lettable area within the building,” says James Scarisbrick, design engineer, Ramboll, London.

Photo courtesy of Tata Steel

The exposed steel column’s smaller footprint maximizes rentable space for the commercial mid-rise.

In fact, HSS’s small footprint contributed to a lettable space increase of approximately 30 square meters, as compared to clad alternatives. Furthermore, the use HSS as internal columns supports 16.5-meter spans of flexible office space, contributing to more than 20,000 square meters of floor space across 12 stories.

The columns, filled with reinforced concrete, were used in 457 millimeter diameter sections at 7½-meter centers around the perimeter of each floor.

“The perimeter columns would have been 610 millimeter sections if we’d taken the traditional route to designing out the intumescent coating,” explains Baalham. “The columns are also far less visually intrusive—the eye is drawn to the building facade rather than the columns.”

“This was a very successful building project,” he adds. “It displayed an exciting new approach to column design, and the architect and client are both very pleased with the results.”

OPTIMIZING MARINA VIEWS OF THE MEDITERRANEAN SEA WITH CONCRETE-FILLED HSS COLUMNS

Supporting the unique twisting columns of Ayia Napa Marina’s 28-story condo towers in Avia Napa, Cyprus, architect and engineer SmithGroupJJR specified concrete-filled exposed steel HSS to minimize column diameter as a means to preserve the spectacular views of the Mediterranean Sea, while addressing high compressive loads and minimizing the congestion of steel reinforcement required in the columns.

Image courtesy of SmithGroupJJR

Currently under construction, concrete-filled exposed steel hollow structural sections minimize the column diameter, thereby preserving beautiful views of the Mediterranean Sea at Ayia Napa Marina’s 28-story condo towers in Avia Napa, Cyprus.

The 30-inch-diameter round steel columns were easily able to achieve the fire rating, without testing, due to the column size.

Image courtesy of SmithGroupJJR

Exterior columns are exposed and located beyond the exterior wall while interior columns are enclosed to simplify planning and detailing of the interior finishes.

The columns also facilitated the usage of steel wide flanges embedded into the concrete two-way slab at each floor level,” explains Andrea Reynolds, S.E., P.E., LEED AP, director of structural engineering, SmithGroupJJR, Detroit. “These were used to transfer shear loads in the slab and keep the slab thickness to a minimum without the need for thickened sections around the columns.”

Primarily located around the building perimeter to keep the interior spaces open, the columns are set in from the slab edge to create a clean finish on the slab.

Image courtesy of SmithGroupJJR

With each residential floor rotating 1.5 degrees, Ayia Napa’s unique twisting design delivers the same floor plan on each level.

PREFABBED CONCRETE-FILLED HSS DELIVER FIREPROOFING AND A SLENDER STRUCTURAL DESIGN AT MICHIGAN STATE UNIVERSITY

At Michigan State University’s Case Hall, prefabricated, 2-hour UL-rated concrete-filled HSS columns were a great fit for a dining area expansion. Placed adjacent to existing columns and along the new perimeter, the new columns were used to create a large volume of open space.

Image courtesy of SmithGroupJJR

Prefabricated, 2-hour UL-rated concrete-filled HSS columns create a large volume of open space at Michigan State University’s Case Hall dining room expansion.

“The new dining area is bisected by a great room,” explains Andrea Reynolds, S.E., P.E., LEED AP, director of structural engineering of SmithGroupJJR, Detroit, who was responsible for the architecture and structural design on the project. “The great room is marked by a colonnade of round steel columns that consist of round 8.625-inch HSS columns that are wrapped with a concrete inner layer and a round steel outer layer that is 10.625 inches.”

The fire-rated columns are finished with a clear coat that provides an interesting contrast with the exposed wood structural roof framing. “The height of the new addition was carefully set to align with the existing adjacent building and to be a minimum of 20 feet above the finish floor to eliminate the need for fireproofing,” she adds.