Lessons from Studies of Cladding Pressures at the John Hancock Tower in Boston

In mid November of 1972 Mr. Albert Prouty, Vice President in charge of the construction of the 795-foot John Hancock Tower in Boston contacted me. Windows were still being installed near the top of the building. He asked me to look at an area where some windows had apparently been blown out by the wind. Figure 1 is an Isometric Schematic of the building. The area of blown out windows on the Stuart Street façade is indicated. Figure 2 is a map of the local area and includes a roof plan of the building. The heights of surrounding buildings in stories are also indicated. Most windows in the area shown in Figure 1 had been replaced with plywood, because the windows had broken in strong SW winds even after being replaced. Also, windows in other areas had cracked. A wind tunnel test had been run to determine the design loads for the windows, but the windows had been designed to Boston Code. I obtained a copy of the wind tunnel report.