Page:Popular Mechanics 1928 01.pdf/36

 



the skyscraper reached its limit? Is the tall building becoming impossible for human beings to inhabit?

There is some evidence to indicate that American cities are about to call a halt on these tall structures that reach into the clouds and down into the earth.

Even the physical limits are being approached. The higher the building, the deeper the foundation must go. That is understood, of course. But it is not always so easy to keep on digging to find a solid rock bottom that will sustain millions of tons of concrete, steel and marble.

The thirty-four story skyscraper of the Albany, N.Y., state capital offices has discovered this to be true. For nearly a year the construction crews have been trying to find a solid bottom to support the great building. More than 2,000 concrete piles have been sunk into Capitol Hill, and the bottom needed isn't there. The vast excavation is getting deeper and in places has not yet approached the tops of some of the concrete piles which have been driven into the hill. Meanwhile ten floors of structural steel are in storage awaiting something stable to support them.

While the troubles of the Albany contractors are many, engineers tell of similar conditions that are being encountered as the height of buildings increases. Geologists say that many cities are located on mounds of earth that are just short of liquid in their consistency as far as proper skyscraper foundations are concerned.

The troubles of contractors are illustrated by the amazing experience at Albany. It was estimated that concrete piles imbedded thirty-seven feet into the earth would each support thirty-five tons, and with enough piles the building's height would be assured. The great pile driver sent the concrete log down to within one inch of the thirty-seven foot depth. It took three blows of the five-ton hammer to drive the pile the last one inch and there was but another inch to go. The hammer came down once and hit the pile again and presto! the pile simply disappeared. 