In , because of its valuable contribution to tunnel design and construction, the Holland Tunnel was designated a National Historic Civil and Mechanical Engineering Landmark by the American Society of Civil and Mechanical Engineers. There are 3. There are nine toll lanes that feed the tunnel, and the roadway within is 20 feet wide. Studies were made in Pittsburgh, Pennsylvania by the Bureau of Mines to determine the composition of motor vehicle exhaust gases, at Yale University to determine the effects of carbon monoxide on humans, and at the University of Illinois to determine the amount of power required to operate the ventilation system.
It was concluded that the tunnel's ventilation system would need to keep the carbon monoxide concentration below four parts per 10, Previously, conventional ventilation systems in railroad tunnels were designed to blow air from one portal to the other. Instead, a new type of ventilation system was devised in which clean air would be supplied throughout the tunnel through a fresh air duct located below the roadway with openings at regular intervals. An exhaust duct would be located above the roadway with openings at regular intervals to remove the diluted exhaust fumes out of the tunnel.
Thus, air would be drawn straight up within the tunnel, which would confine the spread of flames in the event of a fire. A foot m long large-scale model of the tunnel was constructed by the Bureau of Mines near Pittsburgh, Pennsylvania to evaluate the effectiveness of the proposed ventilation system. Clifford Holland also traveled to Europe in to study the ventilation systems of tunnels in England, Germany, and Scotland.
The Holland Tunnel has a total of 84 fans in four ventilation buildings that can completely change the air inside the tunnel every 90 seconds. Electric motors with an output of 6, horsepower are needed to drive all of the fans at once, although the tunnel normally operates with some of the ventilation fans shut off and held in reserve.
Construction of the project, then known as the Hudson River Vehicular Tunnel, officially began with a groundbreaking ceremony on March 31, at the foot of Canal Street in Manhattan. The tunnel was dug out from beneath the riverbed using six shields, each of which was a large cylinder driven by 30 hydraulic jacks with a total force of 6, tons 5, t.
Compressed air was used to pressurize interior of shield to keep out the water and muck; after segments of the tunnel are excavated, 2. Five years into the project, chief engineer Clifford Holland suffered a nervous breakdown as a result of the tremendous stress demanded by the work, having spent long hours working at this desk and in the compressed air of the tubes.
He was sent to a sanitarium in Battle Creek, Michigan for rest but died of heart disease on October 27, at the age of His death occurred just two days before the tunnel was to be holed through, and the celebration that had been planned was canceled in respect for the chief engineer. The two ends of the tubes from New York and New Jersey were joined together without fanfare, even though Holland's mathematical calculations led them to meeting within a fraction of an inch 1 cm of each other.
Following his death in October , President John P. By the early 's, ferries across the Hudson River, the only mode of travel between New York City and New Jersey, strained to handle more than 20, vehicles a day.
Fed up with the traffic congestion to and from the city, New York City officials decided to build an automobile tunnel under the Hudson River -- one that would double the daily traffic load across the river. The biggest challenge was ventilation. Without some way of eliminating all the poisonous carbon monoxide from the automobiles in the tunnel, most drivers would pass out before reaching the other side!
Engineer Clifford Holland came up with a brilliantly simple solution: big fans. Inside four massive ventilation buildings on both ends of the tunnel are 84 powerful electric fans that draw fresh air into the tunnel and blow dirty air out.
0コメント