THE HISTORY OF A UNIQUE ENGINEERING ACHIEVEMENT -THE HOLLAND TUNNEL

The 1.6 mile-long (2.6 km) tunnel’s best location for traf- gases, had to be solved.Holland Tunnel was the first fic and street systems, to de- Different constructiontunnel under the Hudson termine the tunnel dimen- possibilities—trench, caisson,River for motor vehicles and, sions, and to plan its plazas. A and shield—were analyzed inat the time of its opening, the novel idea then was to sepa- depth. The great volume oflongest underwater, mechani- rate the entrance and exit river traffic on the Hudsoncally ventilated tunnel in the plazas to minimize street con- River and the soft silty condi-world. gestion. The twin 29’6” (9 m) tion of the river bottom were

SHIELD CAST IRON SEGMENTS Of CONCRETE AIR LOCKTUNNEL’S OUTER LINING BULKHEAD FOR MEN

CUTTINGEDGE

HYDRAULIC ERECTOR ARM MATERIAL CARS AIR LOCKJACKS FOR MATERIALS

LONGITUDINAL SECTION THROUGH TUNNEL HEADINGSHOWING CONSTRUCTION IN RIVER SILT

The tunnel was a tech-nological achievement thatpioneered the solution to themany civil and mechanicalengineering problemsinvolved in its design andconstruction.

Some first-of-their-kind

traffic engineering studieswere instituted to select the

diameter, shield-driven, castiron-lined tunnels, nearlytwice the diameter of earlierrapid transit tunnels, enor-mously compounded con-struction problems. A brand-new problem, that of design-ing a ventilation system toclear the tunnel of noxiousautomobile and truck exhaust

decisive factors in adoptingthe shield method. Numeroustunnel cross sections androadway widths were evalu-ated before making the finalchoice of two-lane circulartubes, each with a roadway20’0” (6.1 m) wide. Thoughnarrow by today’s standards,it was generous at the time.

REAR VIEW OF SHIELD AND PART OF COMPLETEDTUNNEL DURING CONSTRUCTION.

The shield method ofconstruction was invented andfirst used by Marc IsambardBrunel for excavating a tunnelunder the River Thames atLondon in 1825.

The modern tunnelshield is a steel cylinder whose

forward end acts as a cuttingedge. A divided partition atthe front face prevents theriver bottom from enteringthe shield, except as permittedthrough suitable openings forremoval of spoil material. Therear section overlaps thepreviously placed lining ofcast iron rings.

Inside the shield,hydraulic jacks bear againstthe completed tunnel lining,pushing the shield ahead whenpressure is applied. After theshield has been shoved for-ward the distance of one lin-ing ring, segments of the nextcast iron ring are erected andbolted together to extend the

lining under the protection ofthe rear section. In sub-aqueous tunneling, com-pressed air is introduced intothe forward heading of thetunnel to counterbalance thepressure of the water and toprevent water from enteringthe tunnel.

Construction of the Hol-land Tunnel began on October12, 1920. The first shield waserected in the Canal Streetshaft on the New York side.

VIEW TAKEN DURING A SHOVE IN THE SOUTH TUNNEL EAST, JERSEY CITY, SHOWING SILTFLOWING INTO THE TUNNEL THROUGH SECOND LEVEL POCKETS.

On October 26, 1922 com- per half was equipped with a tor used to lift the lining seg-pressed air was introduced in- hood projecting 2’6” (.76 m) ments into place to form ato the shield chamber, and ac- ahead of the shield proper. complete ring.tual tunneling was begun. The Each shield was equipped with The weight of a shield,shields were typically 30’2” thirty 10” (.25 m) jacks with a with all equipment, was about(9.2 m) in outside diameter combined thrust of 6,000 tons 400 tons (363 t), 30’2” (9.2m)and 16’4” (5 m) long. The up- (5,450 t), and a hydraulic erec- in diameter and 16’4”(5m) long.

REAR OF SHIELD-ERECTION OF CAST IRON

TUNNEL RINGS

The paramount challengewas to design a ventilationsystem for an underwater tun-nel specifically intended forinternal combustion poweredvehicles. The combined scien-tific knowledge of Yale Uni-versity, the University of Illi-nois and the United StatesBureau of Mines, augmented

by the ideas and experience ofindividuals and engineers, wasput to the goal of having theair in the tunnel as safe as theair in the open. After a longand thorough investigation, asystem of ventilation,generally called the Trans-verse-Flow Type, was

adopted.

CLOSER RING AT JUNCTION OF SHIELDS, NORTH TUNNEL.

In the Holland Tunnel’stransverse-flow system, freshair is drawn from the outsidethrough one of four ventila-tion buildings and blown byfans into a fresh air duct lo-

cated under each tunnel road-way. The air enters the tunnelproper through narrow slotsjust above the curb, spaced 10

to 15 feet (3 to 4.5 m) apart.Exhaust fans (also located inthe ventilation buildings) pull

the exhaust-laden air throughopenings in the ceiling into an

exhaust duct located abovethe ceiling slab, and dischargesit into the open air throughthe roof of one of the ventila-tion buildings.

SCHEMATIC OF TRANSVERSE-FLOW TYPE OF VENTILATION.

VIEW OF INTERIOR OF NORTH TUNNEL SHOWING TILED MARKERSAT THE NEW YORK AND NEW JERSEY STATE LINE.

GENERAL VIEW OF NEW JERSEY RIVERVENTILATION BUILDING. NEW JERSEYLAND VENTILATION BUILDING INRIGHT BACKGROUND.

BLOWER FAN SB 5 NO. 2, SHOWING MOTOR CHAIN GUARD AND LOCAL CONTROL BOX,NEW YORK RIVER VENTILATION BUILDING. FRESH AIR INLET LOUVERS IN BACKGROUND.

The four ventilationbuildings (two in New Jerseyand two in New York) house atotal of 84 fans, of which 42are blower units, and 42 areexhaust units. They are cap-able, at full speed, of com-pletely changing the tunnel airevery 90 seconds.

Air samples takencontinously from each of the

exhaust ducts in the sevenventilation sections of the tun-nel are passed through analy-zers recording the amount ofcarbon monoxide generatedby tunnel traffic. Constantmonitoring of the analyzersdictates when changes in thespeed of ventilation are needed.

A central control board,located in the SupervisoryControl Room and manned24 hours a day, provides un-broken surveillance of all ven-tilating equipment and tunnellighting. A system of indicatorlights enables the supervisorto locate immediately any in-terruption or variation in theoperation of tunnel equipment.

The Holland Tunnel,between Canal Street in Man-hattan and 12th and 14thStreets in Jersey City, openedto traffic on November 13,1927, has strengthened theunity and economy of theNew York - New JerseyMetropolitan Region and its

port. Today commercial trafficcrosses the Hudson River in

ENGROSSED AND ILLUMINED RESOLUTIONS PRESENTED TOTHE COMMISSIONS BY THE FOUR NATIONAL ENGINEERING SOCIETIES.

minutes, a trip that often took ing efforts to complete it, andhours by ferry. Milton H. Freeman and Ole

The Holland Tunnel is a Singstad.

tribute to its engineers: The Holland Tunnel is

Clifford M. Holland, whose one of the few engineeringdeath resulted from his untir- works named after the engi-

neer who built it. Its design

and construction became the

model for the Lincoln, QueensMidtown, Brooklyn-Batteryand many other tunnels

throughout the world.

CLIFFORD MILBURN HOLLAND 1883-1924FIRST CHIEF ENGINEER OF THE HOLLAND TUNNEL

The Holland Tunnel is

operated by The PortAuthority of New York and

New Jersey.The plaque designating

the Holland Tunnel a Nation-

al Historic Civil and Mechani- cal Engineering Landmark bythe American Society of CivilEngineers and the American

Society of Mechanical En-gineers was presented in 1984.