Repair of a Landmark Building's Façade 230 Park Avenue, New York, NY

Facade repairs in city settings always pose logistical challenges. An 18 month, $7.7 million, NYC Landmark Preservation Commission accepted facade repair program was performed at 230 Park Avenue, a 34-story, 1.4 million SF landmarked office building in midtown Manhattan. The program specified and administrated by Thornton Tomasetti (TT) focused on restoring ornate terra cotta elements that had been deteriorating since the building’s construction in 1929. The building features many architectural facade elements constructed with terra cotta masonry, most notably 3-story tall, free-standing terra cotta columns with one story tall terra cotta bottom brackets and capitals. In order to correlate the degree of cracking evident at the surface of the terra cotta column enclosure to the amount of corrosion loss of the concealed steel column elements, impact echo, ultrasonic pulse velocity, infrared scanning, and invasive probing methods were performed. A finite element model was developed to analyze the behavior of cracks in the terra cotta brackets. Appropriate and cost effective repair techniques, including specially designed stabilization anchors and liquid applied fiber reinforced tension bands were applied. An impressed current cathodic protection system was also installed at certain locations to prevent and monitor steel corrosion. This was a robust repair program accomplished with sensitivity to preservation requirements and it demonstrated that state-of-the-art technology can be cost effective.