Hamilton Garden at the
Kimmel Center,
Philadelphia, PA

Staying cool under cover

When the Kimmel Center for the Performing Arts in Philadelphia was completed, it was discovered that the Hamilton Garden at The Kimmel Center, which was situated on top of the Perelman Theater and intended as a multi-purpose space for special events, could not be used due to the heat generated within the vaulted glass roof.

A climate-controlled and acoustically enhanced space was created inside a glass box within the glass structure of the Kimmel Center without detracting from the grandeur of the space itself.

The structural requirements were complex. The design would ensure limited to no vibration translation into the Perelman Theatre from the rooftop garden above it, and be a light enough structure to ensure insignificant impact on the theater’s main vibration isolators. The structure needed to be strong enough to support assembly use with a deflection sensitive point supported glass wall at the perimeter. And materials for the construction were to be brought into the space through temporary openings in the existing elevator glass and hand standing up steel columns and beams.

The structural solution features lightweight steel fabricated trusses with specialty bottom chord rods provided by Ronstan. The trusses were supported on steel girders supported by corner tube columns. The columns had elaborate vibration isolators fabricated for the base connection and were lowered into new support steel within the fly loft below. No welding was permitted. Careful coordination with theater equipment and mechanicals was a must.

The floor system consists of junior beams with a concrete slab on metal deck supported eight feet on center with specialty floor isolators. Construction logistics regarding leveling the new floors over existing floors (which had a floor elevation varying by almost 2”) was a significant challenge, particularly with a wood floor with an allowable tolerance of 1/8” over 10 feet.

The construction demanded continuous discussions with the design team. Most construction was completed during the overnight hours to minimize disruption to the performances.

The project received the National Council of Structural Engineers Associations Excellence in Structural Engineering Award for New Buildings Under $10 Million and the Delaware Valley Association of Structural Engineers (DVASE) Outstanding Project Award.

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Structural Systems Used

Steel Frame