Imatges de pàgina
PDF
EPUB

stand the winds; yet Mr. Ellet was a great man. Mr. Roebling may be regarded as the great exponent of the suspension bridge in this country. His reputation may well be envied; for while the great engineers of Europe were declaring it was impossible, he went on with the Niagara bridge; and now, after eighteen years' successful usage, it has caused the engineers of the old world to reverse their theories.

He built the Cincinnati bridge, and if, in future times, the suspension shall have become recognized as a thoroughly safe, permanent structure for railway trains, to Mr. Roebling, more than any other, will the credit belong.

The lattice bridge has been and is now a very popular type of bridge. The name will readily convey a correct impression of its general construction. In some respects it is preferable to the tubular. It is less costly and is less rigid, which some claim to be an advantage. As fine a specimen of this kind, perhaps, as can be seen anywhere, is at Cologne, over the Rhine. Its longest reach is 330 feet. It is, however, liable to oscillation.

But yielding everything to the suspension and the lattice that can with reason. be claimed for them, it is questionable whether they possess the elements of perpetuity equally with the arch. We know arch bridges have endured for centuries; we do not yet know how long a railway suspension, tubular, or lattice bridge will continue.

(

The first cast-iron arch bridge was built in 1779, with a span of 100 feet. Many other iron arch bridges have been successfully constructed. They have always been highly esteemed for their strength and durability. The great drawback, perhaps, has been an inability to construct them with a span so wide as to compare favorably with those of other styles. In England, the largest is the Southwark, with a span of 240 feet and a rise of 24 feet. Note this fact, and remember the length of the Britannia, 459 feet, and the length of the Cologne, 330 feet, and then the importance of the St. Louis bridge, with its span of 520 feet, will appear.

Its form is as enduring as any tested by the experience of ages. Its size surpasses that of any, when we consider the true comparison, the length of span. Its material, cast-steel, is the best in the world, ranking with wroughtiron in the ratio of two to one.

The importance of the St. Louis bridge is still further increased when we consider its foundations, their depth, their mode of construction, and the attendant difficulties.

Other engineers of great eminence have proposed the erection of bridges of greater span than this, but it rarely occurs that the location and conditions of the case justify, as in this one, such bold grasp of mind on the part of the engineer, with the no less accompaniment of a proper manifestation of public spirit on the part of capitalists to carry out his design.

Mr. Latrobe, a noted engineer of Baltimore, has expressed his opinion upon the construction of a bridge at St. Louis. He favored the use of piers higher than those of the present plan, requiring a stationary engine to draw the cars from either side to the center in passing over. He also advocated the use of spans 400 and 500 feet in length.

That modern engineers are anticipating something altogether superior to the past achievements, the following remarks of Mr. Roebling are evidence. He says:

"It was left to modern engineering, by the application of the principle of suspension, and by the use of wrought-iron, to solve the problem of spanning large rivers without intermediate supports. Cast and wrought-iron arches, of 100 feet and more, have been quite successful. Nor can it be said the limit of arching has been reached. Timber arches of much greater span have stood for years, and have rendered good service in this country as well as on the continent of Europe. It is worthy of notice, however, and to be cited as a curious professional circumstance, that the best form of material, so profusely applied by nature in her elaborate constructions, has never been used in arching, although proposed on several occasions. This form is unquestionably the cylindrical, combined in small sections, as is illustrated by vegetable and animal structures. Where strength is to be combined with lightness and elegance, nature never wastes heavy, cumbrous masses. The architects of the middle ages fully illustrated this by their beautiful buttresses and flying arches, combinations of strength and stability, executed with the least amount of material.

"The wrought-iron pipe, now manufactured of all sizes and in such great perfection, offers to the engineer a material for arching which cannot be excelled. A wire cable, composed of an assemblage of wires, constitutes the best catenary arch for the suspension of great weights; and, as a parallel to this, if the catenary is reversed, the best upright arch for the support of a bridge may be formed by an assemblage of wrought-iron pipes, of one and a half or two inches diameter or more. Arches of 1,000 feet span and more may be rendered practicable and safe upon this system. I venture to predict that the two great rival systems of future bridge engineering will be the inverted and upright arch-the former made of wire, and the latter of pipe, both systems rendered stable by the assistance of lattice work, or by stays, trusses, and girders."

It has already been stated that the bridge to be built at St. Louis is to be made of cast-steel; and in the meantime, extensive experiments have been going on to thoroughly test the strength of the metal, and no possible precaution will be neglected or effort omitted to make this bridge a complete and perfect success. Although not so great in length as the Victoria bridge over the St. Lawrence, which is nearly two miles long, nor the bridge over the Nebudda, in India, which is one and a half miles long, nor the bridge from Bassein to the main land, which is over three miles long, yet its magnificent spans and stately piers place it far above these bridges in character and structure. And when ance built it will be grander than the Colossus at Rhodes, grander than the Pharos at Alexandria. It will vitalize the commerce of the Mississippi Valley, and unite the great railway chains between New York and San Francisco, the Lakes and the Gulf. When completed, it will place the name of its builder, Capt. James B. Eads, with those of Telford, Smeaton, Stephenson, and other

distinguished engineers of the world. Mr. Eads already stands prominent as one of the most enterprising and public-spirited citizens of St. Louis; and should this bridge enterprise, in which he is more prominent than any other, prove successful, his character and reputation will become the public property of the country, even as the bridge itself will be. Almost proverbial for the invariable success attending everything he undertakes, and with a world-wide reputation for practical ingenuity and indomitable energy, we hail his prominent identification with this work as an assurance of its successful completion. To him, and to the enlightened, public-spirited citizens who have pledged their capital and influehce to sustain the enterprise, will justly belong the glory that will surely attach to the St. Louis Bridge.

X

PROPOSED UNION DEPOT.

Cotemporaneous with the completion of the great bridge will be the necessity for a grand Union Passenger Depot in St. Louis, where all the railroads leading into the city could receive, deposit, and exchange their passengers with comfort and convenience to the traveling public as well as with economy and dispatch to the different railroad companies. Every day the need of such a building is more and more apparent to the leading railroad interests and the community, as the bridge now constructing approaches its completion.

Acting, therefore, at the suggestion of some of the most prominent and controlling representatives of the railroads leading into this city, and at their request, the Executive Committee of the Bridge Company have selected a site and prepared plans for a proposed structure, which, through their chairman, William Taussig, Esq., they have already submitted to railroad companies and the public.

After examining the whole line of the tunnel, from the end of the bridge to its terminus near the Pacific Railroad track, with a view to a grand Central Depot, the site has been selected, convenient for all the railroads, and central to the business of the bridge.

The buildings have been devised with a view to furnishing all the necessary office rooms for the different railroad companies, and their necessary adjuncts, express and fast freight lines, telegraph, &c., &c., thus combining everything to secure the prompt dispatch of business, and offer all possible inducements to trade and traffic.

The business of the railroads will require at least twelve tracks under the streets and in the depot. The offices for the different railroad, including express and freight companies, can be accommodated above the track, and communicate with it by flights of steps and by elevators.

parate

[ocr errors]
[ocr errors]
[ocr errors]

DESCRIPTION OF DEPOT BUILDINGS AND TRACKS.

The depot buildings will occupy the three blocks from Fifth to Eighth street, between Washington avenue and Green street.

The "track-floor," which will be 20 feet below the level of the streets, will be 297 feet wide, and in length extending from Fifth to Eighth street, with the necessary space cast of Fifth street and west of Eighth street to enter the tunnel at either end.

There will be ten tracks between Washington avenue and Green street, and four tracks under Washington avenue. There well be six platforms from 20 to 24 feet wide, with broad stairs from the platforms to the waiting-rooms

above.

The ten tracks under the three blocks will be inclosed by arched walls three feet thick, and heavy retaining walls on the south side of Washington avenue, and under the curb of the southern sidewalk on Green street.

The streets-namely, Washington avenue, Sixth and Seventh streets-will be supported on iron columns, girders, and joists, and covered with Nicholson pavement.

The interior walls of the building will be supported on iron columns and girders.

The entire three blocks will be covered with buildings, the exterior walls of which will be built of cast-iron, and the interior walls of brick.

The group of buildings covering the block from Fifth to Sixth street will be four stories high, with French roof above; in the first story, and in the west end of the block, six baggage rooms for the railroads, with elevators for baggage from the platforms below, and track to distribute baggage from room

to room.

On the lower story of this building will be the office, reading-room, billiard and bar room, table-d'hote, barber shop, wash room, &c., &c., of the hotel. There will be an open court in the interior of this building, which will be entered from Sixth street, with a large light-shaft in the same to track-floor below, also an entrance on Fifth street.

The third and fourth stories of the building to be appropriated to guests' rooms, and the fifth story, or French roof, to the kitchen, laundry, and general stores, boilers, machinery, and the general working departments of the hotel This fifth story to be reached by four large elevators: one to serve the ordinary on second floor, and table-d'hote on first floor; one for passengers, and one for baggage; and one for general use, elevating of stores, fuel, &c. On the first floor, in Green street, will be a yard in connection with the elevator for the reception of stores, fuel, &c. Also in the yard will bo contained the receptacle for the kitchen refuse, &c., conveyed from thence by large iron pipes. The water and soil from laundry, &c., to be conveyed to sewers beneath the trackfloor.

In the first story of the block between Sixth and Seventh streets will be the ladies' and gentlemen's waiting-rooms, ticket and telegraph offices, with stairs. from the waiting-rooms to the tracks below. These waiting-rooms will be

provided with ample accommodations for washing, &c., and with stairs from the eastern ladies' waiting-room to the hotel above.

There will be room for seven large offices on Washington avenue, and seven on Green street-eight of them 23 by 46 feet; two, 30 by 40 feet; two, 35 by 46, and two 18 by 46 feet.

In the first story, from Seventh to Eighth street, there will be fourteen offices on Washington avenue and Green street: twelve, 23 by 46 feet, and two 18 by 46 feet. On Eighth street, Washington avenue, and Green street, there will be three large express offices. Those on Washington avenue and Green street will be 113 by 46 feet, and that on Eighth street 132 by 45 feet.

The express offices will be furnished with every convenience, as elevators for raising and lowering goods from platforms on track-floor below.

In the second, third, and fourth stories of these buildings will be 330 large and commodious offices and rooms, independent of those designed for guests' rooms in the hotel. These rooms will be furnished with all modern conveniences, and will be accessible by commodious stairs at proper intervals, and have communication to same from balconies around the court, over trackfloors.

The whole space between the buildings on Washington avenue and Green street, from the east side of Sixth street to the rear of buildings on Eighth street, will be covered by a dome-shaped glass roof, and will be 700 feet long by 135 feet wide.

The track-floor, besides being lighted by the glass roof, will be illuminated from the sidewalk, by Hyatt's patent lights, all around the building.

It is proposed to make the building practically fire-proof, by the substitution of iron for beams, girders, joists, partitions, etc.

The general style of the exterior will be Franco-Italian, and, being of iron, will necessarily be ornate.

RAILROADS.

The following roads will use the Passenger Depot-all of them, except those marked *, having their lines now running into the city:

1. The Missouri Pacific.

2. The North Missouri.

a. The St. Louis, Council Bluffs and Omaha ;*

b. The St. Louis and Keokuk;* both coming in on the North Missouri Railroad track.

3. The South Pacific.

4. The Iron Mountain.

5. The St. Louis and Indianapolis.

6. The St. Louis, Vandalia and Terre Haute.

7. The St. Louis and Chicago.

8. The Ohio and Mississippi.

9. The Decatur and East St. Louis.

10. The Rockford, Rock Island and St. Louis.

11. The St. Louis and Belleville, and its Eastern connections.

12. The St. Louis and South-Eastern.

« AnteriorContinua »