Imágenes de páginas
PDF
EPUB
[merged small][graphic][subsumed][merged small]

Steamer Built at Newark Bay Shipyard Passing Through Present Draw. Compare Steamer and Bridge. 3rd Plan: A rerouting of the Central Railroad of New Jersey between Elizabethport and the Communipaw Yard, via Newark.

4th Plan: A rerouting of the Central Railroad of New Jersey between Elizabethport and the Communipaw Yard, to the Oak Island Yard crossing, and thence across Newark Bay parallel with the Pennsylvania and Lehigh Valley Railroads.

1st and 2nd Plan-Construction of a Tunnel CONTROLLING FACTORS IN THE DESIGN OF A TUNNEL ACROSS NEWARK BAY

[blocks in formation]

"The approach cut on the east side at Bayonne, for the electric tunnel, is depressed from Avenue C, so that present operations may be maintained for the entry into this vard from the east.

"The same is true regarding the long depressed cut for the Steam Tunnel extending to 21st Street, but any tunnel will interfere with the present operation of the Bayonne yard, in that no main line approach to same will be possible from the west. It can only be operated by

an in-and-out connection from the east. 3rd-Elevation, Depth, Grade, Etc.

"The grade is fixed to produce a clearance of 40 feet below low water. Assuming a 2% grade for an electrically operated tunnel, the clearance may be retained across the Bay at the west approach, and will retain it from the east end of the present channel with only a slight rise in the roof over the desired depth inshore from this point 600 feet to the pierhead line, the 2-09/100% grade meeting the present track elevation west of Ave. C. "With the 1% steam-operated assumption, however, the 1% descending grade from Elizabethport reduces this

required clearance to 5 feet at the pierhead line at the west end, and only reaches the desired clearance 3,200 feet to the eastward from the west pierhead line.

"At the east end the rising up grade for the approach is fixed at the same point as in the 2% tunnel, or at the east side of the present channel.

GRADES ADOPTED

Electric Tunnel-2% Grade:

"Ruled by dropping on 2-09/100% grade from Ave. C until clearance is obtained, maintaining clearance across Bay to pierhead line, then rising to near junction, producing a 1-44/100% grade.

Steam Tunnel-1% Grade:

"Ruled at the east end by the same fixed clearance of 40 feet at the east side of the present channel (same as 2%), then rising on 1-12/100% grade, meeting present elevation west of the undergrade crossing at 21st Street. Ruled at west end by depressing east of Elizabethport crossing on 1% grade until clearance is reached in Bay. All of these factors are regarded essential and have been weighed in finally deciding upon the profile of the two tunnels.

DISCUSSION OF ASSUMED GRADES

"The 2-09/100% grade for the electrically operated tunnel is the minimum obtainable and is considered satisfactory.

"In adopting by compulsion as described above, the minimum 1-12/100% grade for a steam operated tunnel, it is admitted that it would be very desirable to reduce it. "As ruled by three governing factors, the Elizabethport crossing, the undergrade crossing at 21st Street, Bayonne, and the clearance, the 1-12/100% grade appears to be the best obtainable.

"In order to compare this grade with other practice, brief mention is called to the following:

"Most of the trunk lines entering New York operate on main line grades which, for certain sections, are almost as heavy and in some instances approximately this grade.

Penn R. R. Grades

Allegheny Tunnel to Johnstown, 23 miles-grade 9/10%.
Allegheny Tunnel to Altoona, 11 miles-grade over 2%.
Philadelphia to Bryn Mawr, 13 miles-grade 87/100%.
Downingtown to Malvern, 11 miles-grade 55/100 %.

[blocks in formation]

SKETCHES SHOWING METHOD OF PROCEEDURE

FOR CONSTRUCTING TUNNEL BETWEEN BAYONNE & ELIZABETHPORT, N.J.

[blocks in formation]

NOVEMBER

1922

HARBOR AND MARINE REVIEW

6

[blocks in formation]

HARBOR AND MARINE REVIEW

[blocks in formation]

"Accepting the location of this tunnel as being final where it is shown on the profile, and that it cannot be raised on account of the clearance required, or depressed without further increasing the grades, attention is called to the location of the rock. The lower part of the tunnel is in rock, while the larger upper section is above the rock for practically its whole length.

"While an open trench is not known to have been undertaken of such magnitude, the location of the rock and some other features appeared to indicate that this construction might be cheaper than the shield-driven or subaqueous method. As to the possibility of creating such a dry trench, reference is made to a few instances where the same principle has been applied in extensive work. The principle referred to being the application of the steel sheet pile in certain combinations of form.

"Probably the two greatest works of similar nature are to be found in the unwatering of the Maine in Havana Harbor, and in the construction of the Coffer Dam at West 46th Street, New York. The latter work was designed and constructed under the direction of the writer, see paper No. 1391, American Society of Civil Engineers, "Unusual Coffer Dam for 1,000-Foot Pier, New York City," by C. W. Staniford; and pamphlet of Lackawanna Steel Co., pages 82, 83, 84. In this work, steel sheet piles, 70 feet in length, greater than required here, were driven to rock, and the interior basin maintained dry for rock blasting, wall building, with comparatively no pumping.

"A detailed estimate for a tunnel using this method has therefore been made, assuming unit quantities and liberal costs involving plain methods of construction in the open, but resulting in a very much higher cost than if performed by the shield method.

"Work in open trench neccessitates the building of a temporary diverting railroad trestle and draw, which with a newly dredged temporary channel has been added to the cost.

"It necessitates the use of a tremendous amount of bracing. It also necessitates the use of a tremendous amount of steel sheet piling, which not only has a fairly well known recoverable value, but much of it might be and has been used a second time, depending upon the ingenuity of the contractor, and his judgment in the selection of his working sections. On account of this uncertainty, and because so large a tonnage of steel would be a burden upon the contractor for a long time, the estimate has not been decreased on this account. Actual plans and bidding, however, might easily reduce the estimate by a considerable amount.

[blocks in formation]
[graphic][merged small]

In This Drawing the Artist Visualizes the Proposed Tunneling of Newark Bay by Engineer Charles W. Staniford. This is the Open Trench Method, and it Has Been Explained That it Would Be a Comparatively Simple Task to Lay a Vehicular Tunnel at the Same Time the Rail Tunnel is Constructed. A Vehicular Tunnel to Bayonne Being Needed Urgently Now in Order to Relieve the Burden From the Lincoln Highway Through Newark and Jersey City.

[merged small][merged small][ocr errors][merged small][merged small][merged small]

January, 1923

THE PORT OF NEW YORK
HARBOR AND MARINE REVIEW

Other Features of Staniford Report
The remainder of Mr. Staniford's report consists,
largely, of detailed figures of cost of the alternative
methods of constructing the tunnel, electric as compared
with steam power in the tunnel; subaqueous methods, in-
volving use of shield and cost thereof, if of steel and
concrete, either electrical or steam power; cost of shield
method, with concrete pre-cast blocks, electrical or steam;
electrical installation (which he places at $3,100,000);
cost of right of way ($1,000,000); cost of electrical and
steam tunnel approaches compared, and then

Engineer Staniford's Conclusions On Tunnel
Proposed Tunnel

"The method by open trench was examined into carefully, as on account of the location of the rock:

1st: it appeared attractive from a cost standpoint; 2nd: it made a short tunnel possible at the expense of heavy approach cuts; and

3rd: ventilating shafts were simple in construction. "Its cost and other extreme construction methods, however, place it in an unfavorable position as compared with some subaqueous method.

"In the use of the shield an economy is effected by increasing the length of the tunnel at the east end, and consequently decreasing the extent of the approach cut This is undesirable for the steam tunnel, but is permissible for the electric.

"The steam operated tunnel on a 1-12/100% grade can be built and operated, but has the disadvantage of being

mechanically ventilated. The ventilating shafts create objectionable islands completely across the bay. The extremely long and expensive approach cut on the east and with added expense of land acquisition, all of which places it secondary to the electrically operated tunnel on the 2-09/100% grade.

"It is, therefore, recommended that even without electrifying the whole New York approach of the railroad, that serious consideration be given to the construction of a tunnel to be electrically operated at the location and with the grade selected, the construction to be undertaken by subaqueous methods, under one of the methods upon which estimates have been made, or by some other method which may be presented when the time comes for detailed studies of such a tunnel, by those who specialize in actual tunnel construction.

METHOD NO. 3

Re-routing the Central Railroad of New Jersey from
Elizabethport Through Newark to Chapel Avenue
"The entrance to the Communipaw yard is at Chapel
Avenue from the west. The rerouting consists in the use
of the present line from Elizabethport to the Hackensack
River, making it a four-track line except at the bridges,
then building a new double track freight line from the
Hackensack River, and entering the Communipaw yard
at Chapel Avenue.

Comparison of Distances:
From Elizabethport to Chapel Avenue, pres-
ent line through Bayonne

6.74 miles

[subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][merged small][merged small][merged small][graphic][subsumed][subsumed][subsumed][subsumed]
« AnteriorContinuar »