Back on the Map: The New York State Pavilion's Construction

The most cutting edge engineering and construction technology were employed in order to realize Johnson’s vision for the Pavilion as the largest state pavilion and tallest structure at the Fair, with a record breaking free-span roof the size of a football field. For example, not only was the bicycle wheel roof the first of its kind to be constructed, but it was also completely assembled on the ground and then carefully jacked on the top of the sixteen columns and fitted into place. The engineering and construction feats were interesting enough to the general public to be featured in an article in Popular Science magazine shortly before the Fair opened.

Another technological innovation used to construct the Tent of Tomorrow was slip-formed concrete. As the name suggests, the process is a sliding-form method of construction to support the pouring of concrete structures. In the case of the New York State Pavilion, slip forms were raised vertically for each of the columns and towers as the concrete was placed. Vertical slip forms are usually raised by hydraulic or screw jacks and are commonly used for constructing walls, silos, or bins. Once the placing of concrete begins, it continues until the top or the end of the structure is reached, creating a monolithically poured concrete structure.

slipad

Most of the structures at the 1964-65 New York World’s Fair, including the New York State Pavilion were designed to last only for the duration of the Fair. As a cost saving measure, many of the Pavilion foundations were constructed using wooden rather than concrete or steel piles. Normally, wooden pilings used for permanent applications would be treated with a chemical called Creosote in order to prevent wood rot. As these pavilion foundations were only intended to be temporary, many of the foundations of the Fair’s structures, including the New York State Pavilion, were not treated with preservatives.

For each of the columns of the Tent of Tomorrow, twenty-six untreated wooden piles were driven with some additional steel piles where the foundation did not reach bearing capacity. Typically, untreated wooden pilings can still resist rot as long as they remain submerged below the soil’s water table. When the Fair Corporation decided to retain the New York State Pavilion as part of the post-fair park, it was recommended that the water table be raised to the top of the piles to resist deterioration.

After performing sub-surface investigations in the early 1990s, engineers found that the wooden pilings exhibited significant rot, suggesting that no action had been taken to raise the water table. Since the structural investigation in 1992, the Park Department has contracted surveyors biannually to check established benchmarks for settlement and displacement. According to the City, only a negligible settlement from the structure’s original benchmark has been recorded to date. Despite these findings, the true present condition of the foundation remains unclear without further subsurface investigation.

The steel piles under the columns of the Tent of Tomorrow were found to be in good condition. Fortunately, the foundations for the towers demanded only steel piles. Although no sub-surface investigation has been conducted for the towers, the condition of the steel piles is assumed to be similar to those found beneath the columns of the Tent of Tomorrow.