A Complex and Innovative Engineering Feat

A Complex and Innovative Engineering Feat. . , The entire Hoboken Terminal, with the exception of the baggage wing, is built over water averaging about twenty feet deep. Below the water are layers of mud, sand, and gravel with a total thickness of about 100 feet; bedrock is at a depth of approximately 120 feet. Required to build a lightweight fireproof structure, sufficiently flexible enough to withstand uneven settlement while rigid enough to withstand the impact shock of the ferryboats, Kenneth Murchison's engineer Charles Hurlbut designed a riveted steel framework enclosed entirely in concrete., Each steel column of the structure is supported on a group of from nine to twenty five wood piles, from 80 to 90 feet long; the maximum pile load is about eight tons. The piles are cut off at low water and capped with 12 x 12 in. timbers, which is laid solid timber flooring. The average difference between low and high tides is about five feet, so the woodwork is entirely submerged about two-thirds of the time and is always wet, reducing risk of decay., The steelwork, with the exception of the main roof trusses, is encased in concrete. Rigid connections were avoided to accommodate uneven settlement in the pile foundation and shocks caused by ferry boats bumping against the structure. Rather than employing rigid bracing techniques, curved knee braces were used. The copper sheathing and ornament were attached to holes in the concrete. The copper ornament, formed in the shop of Herman and Grace to Murchison's architectural designs, was reinforced with strap iron angles riveted to the back., The ferry facilities were distinguished by Eugene W. Stern's patent bridge, an unusually flexible, two-tiered structure which improved upon standard ferry bridge design. Stern's two-tiered structure permitted an effective and inexpensive means for adjusting the terminals of both the upper and lower decks at the same time., Each ferry bridge consisted of an upper and lower deck, the upper deck supported by columns carried on the lower deck so that the two attached decks moved together with the tide or by a mechanical adjustment. The supporting columns rested on rails, which they could slide along in case of ferry collision.