AGI Case Study: 500 Walnut

INTRODUCTION

The slender glass tower at 500 Walnut Street has been described by architect Cecil Baker as “a flagship of contemporary residential architecture that honors our city’s history yet celebrates its transformation and revitalization.” His firm Cecil Baker + Partners designed the 26-story building for Scannapieco Development Group.

Sited behind Independence National Historical Park, the tower’s glassy exterior nestles carefully out of view of tourists looking from the Liberty Bell toward Independence Hall, while lending a dramatic modern presence to its corner of the city. Mayor Jim Kenney commented at the project’s 2017 opening, “We must continue this trend of both embracing the new and modern while still celebrating our history.”

ULTRA-MODERN

The tower houses 35 luxury condominiums, an automated belowground parking garage, and multiple terraces to afford residents views of their historic neighborhood. The ultra-modern building’s prismatic glass exterior would not have been possible without the skill and craftsmanship of AGI member GMI Contractors, Inc.

“This was a high-profile job,” explained GMI General Foreman Charles Lopuszanski. “The biggest challenge for GMI was the size. It was a very large project with many components, but with determination, we took it one floor at a time and made it work.”

GLASS FROM SLAB TO WALL

The design of 500 Walnut incorporates a floor-to-ceiling unitized window wall system from ESWindows. Where most window wall systems use aluminum slab covers, 500 Walnut features glazed glass slab covers developed specifically for the project. The ESW725 unitized system comes pre-assembled, pre-glazed, and thermally broken. When used in combination with the glass slab cover, the result is a fully structurally glazed curtain wall appearance.

TIGHT TOLERANCES

Installation required positioning the windows, then adding the slab covers. Tolerances were reduced to one-eighth of an inch. “We had to be on the money,” Lopuszanski described. “It was a challenge, but nothing we couldn’t handle. We learned and are now teaching new guys.” GMI is installing a similar system on a current project.