"On This Day" In Engineering History

On this day in engineering history, the first of 51,694 vehicles drove through the Holland Tunnel, a dual-tube structure that passes beneath the Hudson River to connect the island of Manhattan with New Jersey.

Named after Clifford Milburn Holland, the project's first Chief Engineer, the Holland Tunnel consists of a north tube that measures 8,558 ft. and a south tube that is 180 ft. shorter. Some 500 ft. longer than New York's Lincoln Tunnel, the Holland Tunnel also features 700,000 more ceiling tiles for a total of 4 million.

Construction Begins

Construction on the Holland Tunnel began in 1920, seven years after a joint New York-New Jersey transportation commission recommended the building of a tunnel instead of a bridge. After rejecting several proposals for a bi-level structure, the coalition decided upon a twin tube design by Clifford Holland, a Harvard-educated engineer who, in the words of the Brooklyn Daily Eagle, "sees in a tunnel all the allurement which a mole finds in a nicely constructed burrow". Holland's two-duct design called for one duct to draw-in clean air and the other to exhaust dirty air. Air movement would be controlled by 42 blowing fans and 42 exhaust fans in four ventilation buildings.

Cast Iron and Concrete

On a good day, teams of construction workers called "sandhogs" advanced 40 ft. Their progress followed the movement of two massive, hydraulically-powered, cast iron shields. Each shield weighed 400 tons and had a forward thrust of 6,000 tons. As the sandhogs advanced behind their 16-ft. long shields, they shoveled away mud and blasted through rock. The construction crews also bolted together iron rings – some 115,000 tons in all – and poured 130,000 cubic yards of concrete to form the lining of the Holland Tunnel.

The Sandhogs Succeed

Early in 1927, two brothers met beneath the Hudson River when the teams of sandhogs that they commanded finally "holed through". Later that year, when the Holland Tunnel was finally complete, President Calvin Coolidge traveled to Manhattan to press a golden lever that parted American flags on both sides of the tunnel – allowing vehicles to pass at one minute past midnight. Absent from the festivities were Clifford Milburn Holland, who had died during surgery in 1924, and 14 sandhogs who had given their lives to build this engineering marvel.

Resources:

http://www.nytimes.com/1994/06/27/nyregion/a-tunnel-holland-named-us-historic-landmark.html

http://www.nycroads.com/crossings/holland/

http://en.wikipedia.org/wiki/Clifford_Milburn_Holland

http://en.wikipedia.org/wiki/Holland_Tunnel