Veneer Fastening Now and Then

by Don Friedman on July 13, 2016

The east facade of the Brookfield Place* Winter Garden, yesterday:

IMG_1587

You’re seeing three different fields of focus here – the interior of the building, the glass surface of the facade, and the reflection of the World Trade Center site across the street – but I’m only interested at the moment in the facade.** At each corner of each glass panel is a stainless steel connector, so there is a group of four connectors at each corner where four panels meet. It’s hard to see from outside, but the connectors are similarly attached to interior glass mullion panels set at right angles to the facade plane. There is a bead of sealant where the glass panels meet, but its job is weatherproofing only, since the steel connectors are doing the structural work. This is a significantly different system than those glass curtain walls that use structural adhesives to attach the exterior glass panels: the steel-connector system has visible structural connections, but has the physical advantage of isolating the two quite different functions of load support and weather enclosure.

Just like yesterday’s post, there’s a “but” coming…

I’ve seen this detail before, in pre-glass-wall construction. I’ve probably seen it many times, but the example that jumps to mind is the 1906 Postal Savings Bank in Vienna by Otto Wagner:


2447733417_0aff550d27_o Attribution: Rory Hyde

Here’s an essay with a view of similar bolted-stone veneer connections at the bank’s interior: Wagner, Postal Savings Bank, Essay by Dr. Elizabeth M. Merrill.

The phrase “structural honesty” gets bandied about, sometimes, in architecture. Here it is, from both the early 1900s and from the early 2000s. The easiest way to connect two pieces of material is to use connectors (broadly defined) not glue (broadly defined). The non-structural skin (glass or stone) of a (steel or concrete) frame building needs to be supported for its own weight and for wind load; the most straight-forward way to do so is to bolt it to the supports (exposed or hidden) behind.

A good solution is good regardless of the year.


*Nee the World Financial Center.

** It turns out taking a picture of a glass facade in lighting that doesn’t create intense reflections is not so easy.

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