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The Helmsley Building at 230 Park Ave in Manhattan.

Helmsley Building – 230 Park Ave

  • COMPLETION DATE
    2010

Overview

230 Park Avenue, originally the New York Central Building, is a Beaux-Arts style, 34-story office building. It is a designated New York City landmark. The façade is characterized by distinct terracotta elements, including 32 free-standing, three-story fluted columns consisting of hollow terracotta masonry cladding around brick encasement, supported by a central core of built-up laced steel columns. At each column, there is a terracotta bracket at the 28th floor and a top bracket at the 32nd floor. The façade also has seven-foot terracotta buffalo heads at the top of the piers at the 16th floor setback.

The repair project ranged from brick replacement to repair of leaks at the crown. The greatest engineering challenge was the analysis and repair of the large-scale terracotta columns and brackets which are the most notable features of the landmark façade. A preconstruction survey of the building revealed large-scale cracking in these elements. Impact echo, ultrasonic pulse velocity, infrared scanning, and invasive probing were performed and a finite element model was developed to analyze the behavior of cracks in the building’s terracotta brackets. This revealed a high stress concentration that closely matched the observed diagonal cracking. Appropriate and cost effective repair techniques were then implemented, including specially-designed stabilization anchors and an impressed current cathodic protection system.

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