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Case Study

The American Copper Buildings

Sectors: Structural Engineering
Applications: Connecting cladding to a skybridge

Summary: Lindapter Girder Clamps provided a solution for connecting cladding to a skybridge between two skyscrapers.

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Location: Manhattan, New York City
Market: Structural Engineering
Product: Type AAF Girder Clamps
Quantity: 600
Contractor: JDS Development Group

Project Background
The American Copper Buildings is a luxury residential development which consists of an angled pair of copper-clad skyscrapers. The two structures which stand at 41 and 48 stories are located at 626 First Avenue, and contain a total of 761 luxury rental residences. The eye-catching buildings on the East River waterfront were designed by SHoP Architects and constructed by JDS Development.

Client Requirement

During the early design stage it became apparent that planners would not allow the two buildings to be connected at grade due to zoning, and so the solution was to connect both towers with a skybridge 300 feet above ground level. Due to working at height, a drill and weld-free method of connecting a steel framework to underneath the skybridge trusses was required in order to attach cladding panels.

Design Solution

Lindapter Type AAF adjustable high slip resistance girder clamps with a combination of 5/8” and ¾” diameter grade A325 bolts were specified to connect the steel framework. The design incorporated a 4-bolt, 900 angle connection with steel location plates that avoided the need to drill or weld. Type AAF girder clamps also have a hot dip galvanised (HDG) finish which provides a high level of corrosion protection. The decision to use Lindapter Type AAFs was influenced by independent technical accreditations, which include ICC approval for structural and seismic design.


The contractor used over 600 Type AAF Girder Clamps to connect the steel framework to the main steel trusses of the 100 foot long skybridge. Installation was quick and easy as the steel beams were quickly aligned by sliding the beams into the correct position on each truss before tightening the clamp assembly.
The self-adjusting feature of the girder clamp was also beneficial as it allowed the contractor to use just one product on the whole project to suit the different flange thicknesses. Once tightened to the recommended torque the steel framework was securely connected to skybridge. To complete the installation cladding panels were attached to the steel framework.


Type AAF Girder Clamps provided a drilling and weld free connection that was quick and easy to install whilst working at height. The stunning three story skybridge now links the two buildings and surprisingly includes a fitness and leisure complex with a swimming pool on the bottom floor.

Key Benefits

• No drilling or welding required
• High strength capacity and durability
• Hot Dip Galvanised finish provides a cost-effective and low maintenance solution
• Fully adjustable in the field for easy installation

Click here to download the Type AAF datasheet.

Watch our installation video below.