Golden Gate Bridge

“ Formerly the river had to be crossed by a rather difficult ford, but that had been done away with in the time of King John, and replaced by a narrow bridge of eight arches, which in its turn had been replaced in the time of William and Mary by a wider bridge of three arches with a toll-gate upon it, where all traffic except pedestrians had to contribute towards the cost of its erection. ”

“ In that same year (1931) , the George Washington Bridge was opened. This bridge across the Hudson River in New York City reached 3,500 feet between towers. At one bound, it had virtually doubled the Ambassador’s span. Not only that, but it was one of the strongest bridges ever built, with the greatest capacity—eight highway traffic lanes on the upper deck and provision for future rapid transit below (ultimately six highway lanes were added instead) when the stiffening trusses would be added. ”

“ Here indeed is a golden target for bombs and for modern artillery!
Every bridge in the United States of America is a target of this sort in one form or another. There are bonfire timber bridges, for example, exceedingly deft and excessively high; sometimes their piers are nothing more than large wooden frames piled one on top of another, up and up and up, till at last they are tall enough to be known as great sky-ticklers. ”

“ It has a span of 200 feet, with a rise of 42 feet. An arch, however, in the Washington Aqueduct extends to 220 feet span, while the central span in the Southwark Bridge, designed by Rennie, is 240 feet. This last, however, is of cast-iron.
The principle of the arch, however, does not appear first in the history of bridge building. Bridges are as old as mankind; that is, no one knows when first men began to cross streams and chasms by placing the trunk of a tree from one side to the other, and thus bridging the gulf. ”

“ Hence each arch is complete and independent in itself, the piers having simply to sustain their vertical pressure. The arches are six in number, of 125 feet span each, the two approaches to the bridge being formed of cast-iron pillars and bearers in keeping with the arches.
The result is a bridge that for massive solidity may be pronounced unrivaled. It is one of the most magnificent and striking of the bridges to which railways have given birth, and has been worthily styled "the King of railway structures." ”

“ The Bridge has not only been honestly built, but it may be safely asserted that it could not now be duplicated at the same cost. Much money might, however, have been saved if the work had not been delayed through want of means, and unnecessary obstacles interposed by mistaken public officials. Moreover, measured by its capacity, and the limitations imposed on its construction by its relation to the interests of traffic and navigation, it is the cheapest structure ever erected by the genius of man. ”

“ At 27 li from Peking, by the western road leaving the gate of the Chinese city called Kwang-’an-măn, after passing the old walled town of Feuchen, you reach the bridge of Lo-Ku-Kiao. As it now stands it is a very long bridge of nine arches (real arches) spanning the valley of the Hwan Ho, and surrounded by beautiful scenery. The bridge is built of green sandstone, and has a good balustrade with short square pilasters crowned by small lions. It is in very good repair, and has a ceaseless traffic, being on the road to the coal-mines which supply the city. ”

“ The desire for separation of grades led to extensive use of long sections of viaduct construction in urban areas on the Interstate as well as on other freeways. Divided roadways, liberal bridge roadway widths and increased pier and abutment clearances under overpasses became normal safety practices.
The mainline and ramps of the Mission Valley Bridge in San Diego, Calif., are prestressed concrete box girders. Architectural treatment gives the piers an old “Spanish flavor.” ”

“ Myself, I hate such a strumpet of a bridge as the Hoogesluis at Amsterdam, with her ornate spandrils, and her embossed masonry, and her balustraded parapet surmounted by a row of obelisks around which lamps are bracketed. Also I hate such a suspension bridge as the one at Conway Castle, where the metal rods that support the roadway pass through a brace of turrets on each of the embattled gateways. The effect is not only comic but ludicrous. No engineer with any sense would have put a metal viaduct within a few yards of Conway Castle. ”

“ Far too often their ideal of strength was a mere man-at-arms, brave but underbred. Rivers were obstructed by immense piers, for instance, by which spates were turned into dangerous inundations; and footways along bridges were so narrow that safety recesses for pedestrians had to be built out from the parapets into the piers. Even in exceptions to this rule of ungainliness, as in much Spanish workmanship, architects were overapt to make the use of bridges a tiring penance that wayfarers could not avoid. Thus the bridge over the Sella at Cángas de Onis has a lofty footway shaped like a gable ”

“ The approach, however, is dangerous, and requires a skilful waterman, who is obliged to pull his boat into the draft or eddy of the dam before he can make the Lock. Though the works of the New Bridge have at present closed several of the Arches of the ancient edifice, yet the 4th and 5th Locks from the Southwark end have been thrown into one, with a strong wooden vaulting, parapet, and roadway above, to increase the water-way beneath. Since the commencement of these works, the fall of the river has also become less dangerous for barges, from the returning tide sooner meeting with resistance ”

“ The vertical clearance on the truss spans is 21 ft. 6 ins. The roadway on the steel structures across Hayden Island and on the Union Avenue approach is paved with bitulithic pavement and on the Derby Street approach with macadam.
The bridge over the Collunbia River consists of a series of through riveted truss spans with curved top chords; three spans 275 ft. long and ten spans 265 ft. long. together with a small deck girder span at the Vancouver end, making a total length of 3,531 ft. 57/3 ins. between end shoes. Provision for navigation on the river is made by a vertical lift span. ”

“ In the upper of these prospects, the Northern end of London Bridge is shewn to be a passage fenced by wooden palings without any houses, excepting one building, which occupies the whole width of the Bridge; having a gate in it surmounted by the King’s Arms, and standing immediately before the old Church of St. Magnus. ”

“ The span of the big arch is 120 feet, and its height above low-water level is more than 60 feet. The roadway is very narrow, being only 9 feet wide, and it turns abruptly at the wings, as if to close the entrances against wheeled traffic. The quoins of the smaller arches and all the voussoirs of the wide arch are of dressed stone. Every other part of the bridge is rubble masonry bound together with most excellent mortar. ”

“ The present Suspension Bridge which connects the South Stack rock with the Head, was formed in 1827. It is over a chasm 110 feet in width, and built on the same principle as the Menai Bridge, two chain cables passing across, firmly fixed in the rocks on either side, and carried over two massive stone pillars erected for the purpose. The chain supports the platform of timber five feet wide, and 70 feet above high-water mark. The crossing of the bridge to some will be a little trying to the nerves. ”

“ With respect to the Bridge itself, it is filled with buildings, in which the Traitors’ Gate with the heads, the Nonesuch House, and the Chapel of St. Thomas, are particularly visible; whilst above the houses, at the North end, is seen the top of ‘The Water Worke.’ From the windows of several of the houses, buckets are being let down by long ropes into the water, which is seen rushing through the arches with great impetuosity, although there is no fall. ”

“ Small watercarts creep along close to the parapet and insinuate a quiet stream of water, which trickles away across the stone pavement to the gutter and baulks the intentions of dust. The Bridge is cared for by a number of other attendants, who are ever giving it a wash and brush up, ever removing distracted pieces of contents bills and advertisement slips which fly about on its surface, ever begging its pardon and setting it to rights solicitously. ”

“ One example is 234 feet high. It is the great Portage Bridge spanning the Genesee River, in the State of New York, on a railroad between New York and Buffalo. It looks like a miracle of carpentry, this wonderful bridge of frames; its length is 240 metres, and the piers—sixteen romantic scaffoldings—form immense triangles with flattened [Pg 354] summits upon which a double gallery rests as a firm support for the railway. Each scaffolding rises from a pile of masonry nine metres higher than water-level, so that floods do not break their force against the timber frames. ”

“ A cantilever bridge consists of two inverted trussed beams, each balanced on a pier, one part extending over the river and the other to the shore, where it is firmly anchored in solid, heavy masonry. The ends extending over the river toward each other from the opposite piers are joined by a short truss in such a manner as to permit expansion and contraction consequent on changes of temperature, and yet be proof against vertical or lateral pressure. Such a bridge, it is said, sustains scarcely any strain in the center of the span. Each half of the entire bridge is self-balanced on its pier ”

“ This noble work of art, which is unequalled in the history of bridge-building, crosses the Dee at the south-east angle of the Roodeye, and is approached by a new road from the centre of Bridge-street, which passes by the Castle esplanade, proceeds across the City Walls, and then, by an immense embankment, thrown over a deep valley, to the foot of the bridge. The bridge consists of one main stone arch, with a small dry arch or towing path on each side, by which the land communication is preserved on both sides of the river. The cost of erection was £36,000. ”

“ Its length is twelve hundred feet, after the Brooklyn bridge the longest structure of the kind in the world, and it is the narrowest of those designed for carriage travel. To its narrowness it probably owed its safety from destruction during a fierce gale which occurred in the fall of 1869. The fastenings or dowels of several of the guys on the Canadian side were torn out, and the bridge at its center deflected down-stream more than its width, so that the surface of its road-way could not be seen half its length. ”

“ The East River being the locality for most of the foreign shipping, the bridges are at high elevations, the great Brooklyn Bridge, which crosses from City Hall Park, being one hundred and thirty-five feet above the water. Its massive piers are among the tallest structures about New York, rising two hundred and sixty-eight feet. This, the largest 70 suspension bridge in the world, was begun in 1870 and opened for traffic in 1885. ”

“ The Grand Trunk struck into the Prairie Provinces with depots at Fort William, Port Arthur, and many other strategic centres. Mr. Hays had a great idea of the value of bridges. One of his conceptions was a single-span double-track bridge crossing the Niagara Gorge. This was opened in 1897, replacing the suspension bridge opened in 1853. The Gorge Bridge is a splendid piece of engineering, the span of the arch being 550 feet and the width of the railway flooring 32 feet, the lines being 245 feet above water. ”

“ It is a matter of notoriety that railroad bridges are built upon solid abutments of mason-work and resting on piers of stone between the abutments, thus giving strength and security to the frame above. It is not easy to see wherein such a structure differs from an ordinary bridge, except that, as it is to endure a greater burden, it is more solid and substantial. ”

“ Instead of arches resting on piers and abutments, the bridge has a single arch, reaching from one side of the cutting to the other, and springing from the slopes, which it helps in some measure to support. A flying bridge of large dimensions near Weston-super-Mare carries a road across the cutting at a height of 60 feet above the line of rails, with a clear span of 110 feet. ”

“ This firm also had charge of the building of additions to the White House during the administration of President Roosevelt.
EAGLE SURMOUNTING PYLONS
BISON HEAD
The bridge extends from the Lincoln Memorial to Columbia Island, has a length of 2,138 feet, and is 90 feet wide, the width of Fifth Avenue in New York City. The bridge has been built as low as possible, consistent with good proportions, in order not to interfere with the view of the Lincoln Memorial from Columbia Island. There are 6 lanes on the bridge, each 10 feet wide, and 2 sidewalks, each 15 feet wide. ”

“ Don't cross the bridge till you come to it,
Is a proverb old, and of excellent wit. ”

“ The contractors have already completed the iron-work for the “first half” of the bridge; with the exception of this face-work, which will be finished somewhat later. It then only remains for the engineer to complete the road and pathway, and open the bridge for traffic. One obstruction will, we fear, remain. The blocks of houses on either side of the river (ultimately destined to be removed) , still look stable as ever—these abut directly upon the new portion of the structure, and will, if not removed before opening the bridge, make a sharp and inconvenient turn in the road necessary. ”