Part 2: LeMessurier's Innovative Citicorp Design
William LeMessurier was one of the country's most distinguished structural engineers when his Cambridge firm was called upon to act as a consultant to the planned Citibank corporate headquarters. LeMessurier had a vast array of experience with skyscrapers; the first building he designed, Boston's State Street Bank, incorporate an inventive cantilever girder system, and his famous Boston Federal Reserve Bank, was designed so that an airplane could, quite literally, fly directly through what appeared to be a large hole in the building.
LeMessurier's experience with innovative designs was fortunate, sincethere was a criterion peculiar to the planned Citibank building. Achurch had partial ownership of the block where Citicorp planned tobuild. As a resolution, Citicorp agreed to build a new free-standingstructure, located at one corner of the lot, to replace the currentantiquated, dilapidated church. In return, the church granted "airrights" above its part of the block to Citicorp.(Pictured: Thebottom part of the first rendering of the Citicorp tower design, clearly showing the nine-story high, mid-wall-mounted stilts that would need to support the building.)
In order to provide space for the new church, the Citicorp tower would therefore have to be situated on nine-story-high stilts, so the church could be constructed underneath. However, the church was to be located at a corner of the block, not in the middle of a block. This meant that the Citicorp tower's stilts would have to be in the middle of each of its walls, and not at the building's corners -- an unprecedented feat of engineering if it could be accomplished.
The innovative LeMessurier sketched an idea for the Citicorp tower's framework and column support system. (Pictured at left is an eight-story section of his design.) It called for large diagonal girders throughout the building. The girders would transfer the tower's great weight to the four huge columns that would anchor the structure to the ground. The new church could then be constructed as planned, underneath one of the tower's corners.
