ABBAE Reports Condo Window Crack Caused by Exterior Impact

Allana Buick & Bers (ABBAE), an architectural engineering firm specializing in forensic investigation and engineering of curtainwalls, exterior façades, and other building envelope assemblies, was hired by the Millennium Tower Association to study a cracked window glass in Unit 36B of the San Francisco residential high-rise that some suspected of being caused by settling and tilting of the 2009 structure. ABBAE studied the exterior of the 58-story, $350-million structure from October 2016 through February 2018 and again in September 2018 and reported there is no need for further investigation of the curtainwall. The cracked glass was caused by an “exterior impact” and was “unrelated to building movement and settlement,” ABBAE pronounced.

The tallest reinforced concrete structure in the western U.S., containing units ranging from $1.6 to $10 million, has sunk 17 in. and tilted 2 in. since its completion. The settlement is blamed by some on construction of the massive Transbay Transit Center next door, which removed groundwater to prevent soil erosion. The packed sand underneath the Millennium building then compressed and caused it to settle, according to a consultant in 2010. The Transbay Joint Powers Authority denies this accusation and blames inadequate foundation under the Millennium Tower.

Famous tenants at the Millennium include Joe Montana and Tom Perkins.