731 Lexington Avenue Building

The 731 Lexington Avenue Building is a Contemporary skyscraper designed between 1998 and 2001 by César Pelli & Associates, in association with SLCE Architects, and built between 2001 and 2005, for a reported $450 million dollars, in New York, NY.

731 Lexington Avenue Building is not the only name you might know this building by though. It is common for companies to want to attach their names to iconic buildings when they move in, or for the general public to come up with nicknames, and this one is no exception. The building has changed names several times over the years, and is also known as:

• Bloomberg Tower from 2004 until this day.
• Alexander’s Tower from 2004 until this day.
• One Beacon Court from 2004 until this day.

Its precise street address is 731 Lexington Avenue, New York, NY. You can also find it on the map here.

The 731 Lexington Avenue Building has received multiple architecture awards for its architectural design since 2005. The following is a list of such prizes and awards:

• Award of Excellence by the Urban Land Institute in 2005
• Architecture Record Design Award in 2005
• Award of Merit by the Illuminating Engineering Society of North America in 2015

The building, which occupies an entire city block between 58th and 59th Streets, rises above an open public space, an elliptical courtyard, defined by a six-story inverted conical wall known as Beacon Court. This space features multiple formal entrances as well as vehicle access points..

César Pelli & Associates was the architecture firm in charge of the architectural design, in association with SLCE Architects.

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 731 Lexington Avenue Building a reality:

• Thornton Tomasetti in charge of Structural Engineering
• Bovis Lend Lease Ltd. as the Main Contractor
• Larson Engineering in charge of Facade Consultancy
• Otis Elevator Company as the company in charge of the elevators system
• Vornado Realty Trust as the Main Developer
• Flack + Kurz in charge of MEP Engineering
• Jacques Grange in charge of Interior Design

The 731 Lexington Avenue Building can be categorized as a Contemporary building.

The 731 Lexington Avenue Building uses a frame structure made of steel and concrete columns and poured concrete over metal decking slabs.

A frame structure uses a combination of beams and columns to sustain the building's weight. The walls in this case are non-load bearing, which allows for more flexibility when distributing the interior spaces.

The facade uses a non-load bearing curtain wall system. This means the curtain wall modules are anchored to the building's structural frame, typically by being attached to the edge of the floor slabs. The curtain wall system connects to the slabs using brackets, anchors, and mullions, which transfer the loads imposed by wind and temperature changes, to the building's primary structural elements.

This setup allows the curtain wall to accommodate differential movement between the facade and the structural frame, such as thermal expansion, floor deflection, or sway from wind forces. This system's integration with the slab edges also allows for continuous insulation and weatherproofing layers.

A steel and concrete composite structure is used up to the 30th floor, above which it transitions to a reinforced concrete-only structure. On the transition floor, encased transfer trusses were used to redistribute loads between the two structural systems.

To withstand horizontal forces, the tower uses a concrete shear wall core and a tuned mass damper I the residential section.

From an aesthetic point of view, the facade features The curtain wall, which begins where the commercial floors of the atrium end, features integrated fins in certain areas that provide interior shading, projecting up to  33cm from the facade.

Seventeen types of high-performance, low-emissivity glass were used, notably a white glass that stands out at the crown of the tower and lights up at night like a distinctive lantern in the skyline.