Under Our Feet

Everyone knows that New York has subways, so even people new to the city who are fascinated to hear the sound of a train though a grating in the sidewalk are not surprised by it. The underground structures for other trains, including the station yard for Grand Central, are something else entirely. The yard is …

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Excavation As An Extreme Sport

That’s the beginning of the construction of Grand Central Terminal, in 1908. To place everything, both the second and third (current) Grand Central straddle Park (Fourth) Avenue on the north side of 42nd Street. This picture was taken from approximately the line of 45th Street, a half block east of Park Avenue, looking south. Grand …

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Construction History: Grillage Foundations

In any rapidly-changing technology, there are sometimes branches off the main stream that are critically important, highly developed, and short-lived. People work very hard to perfect something that they need, only to have it replaced by something better a few years later. Structural engineering is not now changing rapidly, but 125 years ago it was. …

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Perfect, Buried, and Wrong

I discussed inverted-arch foundations a while back and wanted to briefly return to the topic with this picture. That’s a beautiful example of an inverted arch, carrying the load from two piers in a church apse. The most important thing about it is that it has performed its job properly for over one hundred years. …

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A Local Symptom of a Systemic Problem

For a long time, the standard in New York for excavating foundation pits for new-building construction has been sheeting and shoring. The pit is dug out, by hand or by machine, vertical piles installed at the perimeter and braced with diagonal rakers, and wood plank run between the piles to retain the adjacent earth. It’s …

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