151 North Franklin

The 151 North Franklin is a Contemporary skyscraper designed in 2013 by John Ronan Architects, with John Ronan as lead architect, in association with Adamson Associates Architects, and built between 2015 and 2018, for a reported $184 million dollars, in Chicago, IL.

151 North Franklin is not the only name you might know this building by though. The building is, or has also been known as CNA Center.

Its precise street address is 151 North Franklin Street, Chicago, IL. You can also find it on the map here.

The 151 North Franklin has received multiple architecture awards for its architectural design since 2018. The following is a list of such prizes and awards:

• Digie Award for “Most Intelligent Office Building” in 2019
• Greater Food Depository Commercial Development of the Year in 2018
• LIT Award for Exterior Architectural Illumination

John Ronan Architects, with John Ronan as the lead architect, was the architecture firm in charge of the architectural design, in association with Adamson Associates 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 151 North Franklin a reality:

• Magnusson Klemencic Associates in charge of Structural Engineering
• Lendlease Corporation as the Main Contractor
• Environmental Systems Design in charge of MEP Engineering
• Wolff Landscape Architecture in charge of Landscape Architecture

The 151 North Franklin can be categorized as a Contemporary building.

The 151 North Franklin uses a framed tube-in-tube structure , with concrete 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.

From an aesthetic point of view, the facade features a laminated, frosted, mirrored glass curtain wall, framed by thin dark steel frames that mark the height of each level.

An exterior staircase on one side of the structure leads to a public terrace on the second floor. The rooftop terrace, exclusive to tenants, extends the building's glass exterior cladding, creating a protective wind barrier.