Land bridge

“ 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. ”

“ Where the topographical conditions are such that bridges can be made of such heights, without prohibitive cost, as to permit, at all navigable stages of water, the passage of boats best suited to the river commerce, it is for the best interest of both the land traffic and the river traffic that bridges be so constructed. ”

“ 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. ”

“ The bridge is so overhung and shut in by trees that you scarcely notice it to be a bridge at all; but if these be early summer days and the season not exceptionally dry, the brook can be heard hoarsely plunging beneath, over a quite respectably large weir. When Mistress Anne Hathaway lived at the farmhouse now called her cottage—which is an entirely wrong use of the possessive case, for it never belonged to her—Shottery Brook was to be crossed only by a watersplash for vehicles, and a plank footbridge for pedestrians ”

“ For this work required nothing more than imitation, while the eagle-beaks added some invention to a deft handicraft. Many an earthquake had made a slab-bridge, and other [Pg 124] models were formed by the lava from volcanoes which hardened into a thick crust over many gaps in the land.
From these bridges—a tree cut down with a flint axe, and a single boulder or slab laid from bank to bank of a stream—came three lines of descent in very slow, yet fertile handicraft; and to the history of each a long book could be given. Let me name them one by one:—
1. ”

“ Great marble bridges of a single span stretch from mountain to mountain over deep chasms. Nothing can be more imposing than the construction and the situation of those bridges, cast into space as it were, and swimming in the white, moist atmosphere which seems to fall regretfully into the ravine. The road passes from one side of the gorge to the other seven times in the space of four leagues. When our travellers crossed the seventh bridge, they saw at the bottom of the gorge, which widened almost imperceptibly before them, the charming valley of Luz, bathed in the flames of the rising sun. ”

“ As a rule, these road-bridges are simple and inexpensive in character, except in towns, or in cases where the line crosses the roads very obliquely, or where the road is situated at the top of a deep cutting, or bottom of a high embankment. Away from towns and out in the open country, permission is generally obtained to divert the roads to a moderate extent, so as to obtain a more favourable angle and height for the bridge; but in towns, where the roads become streets, sometimes of great width, with houses and shops on each side, little or no diversion can be allowed. ”

“ Only rarely does one see the hut of rough logs and clay that denotes the settler, only occasionally is there a station, or a mill or a logging camp in this womb of loneliness. Only occasionally does one cross one of those lengthy and rakish spider bridges that give a hint of man and his works.
On a long bridge, over the Montreal river, we made the most of man and his works. It is a lengthy, curving bridge, built giddily on stilts above the boulder-strewn bed of a wicked stream. We were admiring it as a desperate work of engineering, when the train stopped with a disconcerting bump. ”

“ He crawls along fallen trees over some torrents and chasms; across a flooded river here and there he leaps in a shambling, lopsided fashion, when stepping-stones and boulders rise above water-level; he roams into hilly districts where many a ledge of rock spans a dangerous gap; but he enjoys himself most of all when a suspension bridge of branches enables him to amble from tree to tree across a deep-lying river pent up between high cliffs. ”

“ 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. ”

“ 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." ”

“ A bridge of eight arches spans the water before it runs out to sea, the bank on its further side rising into a line of plough-fields crowning the cliffs, where flights of gulls follow the ploughman, and hover in his track over the upturned earth. As the turnpike runs down to the bridge, it curls round the policies of a harled white house which has stood for some two hundred years a little way in from the road, a tall house with dead-looking windows and slates on which the lichen has fastened. ”

“ Entering a tunnel in the vast wall of rock the train emerges again at one end of the bridge, and after crossing the gulf turns along the other side so that for some long time this narrowest part remains in sight, the maroon red ironwork of the bridge staring dramatically in the centre of a desolate landscape of silver grey. No patch of grass or shrub or any other live thing is to be seen—only the immensity of the scale is marked {289} by one small block-house, a minute sentinel which shows against the sky on the tallest height of cliff. ”

“ It is no use my reminding you that no railroad goes to the old home place. It isn't there any more, even in outward seeming. Cummins's woods, where you had your robbers' cave, is all cleared off and cut up into building lots. The cool and echoing covered bridge, plastered with notices of dead and forgotten Strawberry Festivals and Public Vendues, has long ago been torn down to be replaced by a smart, red iron bridge. The Volunteer Firemen's Engine-house, whose brick wall used to flutter with the gay rags of circus-bills, is gone as if it never were at all. ”

“ The aspect of solidity and permanence is remarkable. Even the temporary bridge over the Ussuri, 1,050 feet in length, a trestle bridge of heavy timber to resist the impact of the ice, is so massive as to make the great steel bridge, the handsome abutments of which were already built, appear as if it would be a work of supererogation. ”

“ The navigation of the river thus remains unobstructed—for many vessels proceed to the staiths above the bridge for the purpose of taking in their coals—while the inhabitants on each side enjoy all the advantages of facilitated intercourse. The breadth of the bridge at the top is thirty-two feet including the footpaths on each side; and the carriage-way is formed of lime, marl, and gravel, above a flooring of timber, which is laid across the iron ribs of the arch. ”

“ In trail and road construction it is very often necessary to build bridges. Sometimes a very simple log bridge meets the need, but in bridging many large mountain torrents, which become very high and dangerous in the spring, large bridges are necessary. Cable suspension bridges and queen and king truss bridges are built where occasion arises for them, but only after being planned in detail and after the District Forester has approved their design and method of construction. ”

“ 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. ”

“ The center of its wondrous arch is forty feet in perpendicular thickness and sixty feet wide, while the span is exactly eighty-nine feet. A public highway utilizes the bridge, and it is the only means of passage for wagons within a mile either way, except by a steep bank, very difficult to ascend, a short distance below the gorge. Just above the bridge the creek bluffs are broken into masses that look like immense buttresses, pinnacled at places and reaching to a height of 250 feet. ”

“ These were approaches to the big covered bridge spanning the main channel of the Madawaska River, and when swelled by the spring thaws and rains, the two flanking channels divided at the foundations of the house, and rustled away through the narrow paths of the small bridges to the rapids. You could stand at any window in the House and watch the ugly, rushing current, gorged with logs, come battering at the wall, jostle between the piers, and race on to the rocks and the dam and the slide beyond. ”

“ You are standing aloft, balancing yourself upon tiny planks at the steadily advancing end of the bridge, as it forces itself over a stream of formidable width. Overhead, a gigantic, ungainly traveller, equipped with steel derricks at every corner, is advancing foot by foot as the bridge advances foot by foot. Underneath, through the thin network of planks, of girder and of supporting false work, you can see the surface of the river a full hundred feet below. ”

“ Every situation that confronts the bridge builder requires different handling; at one time he may be called upon to construct a bridge alongside of a narrow, rocky cleft over a rushing stream like the Royal Gorge, Colorado, where the track is hung from two great beams stretched across the chasm, or he may be required to design and construct a viaduct like that gossamer structure three hundred and five feet high and nearly a half-mile long across the Kinzua Creek, in Pennsylvania. ”

“ The new high-level bridge, carrying the railway only, was opened by King Edward VII. in 1906; it consists of four steel spans on granite piers. The hydraulic swing bridge, on the low level, was built to replace a stone structure erected in 1781 on the site of a bridge dating from 1250, and destroyed by a flood in 1771. The Roman bridge, the Pons Aelii, is said to have spanned the river at the same point. The hydraulic bridge (1876) consists of one large centre pier, two midstream piers and two abutments; and its foundations are iron cylinders resting on the solid rock, 60 ft. ”

“ On the river the white wooden bridge has been pulled down, and a huge, red, brick structure, like a ponderous railway bridge, hideous, grotesque, and shutting out all the sylvan view up stream, has been erected in its stead, altogether unfitted for the slender rural traffic which alone passes there, and costing a heavy price, levied by taxation from a rural, and far from rich, community. ”

“ At this spot a bridge has existed for several centuries; but the present structure is quite modern. It is far more commodious, but to the artist less attractive, than its predecessor. That was narrow, built on a curve, consisting of thirty-six arches, hardly any two of which were alike; this is wide, uniform, and strikes straight across the broad valley from bank to bank. Like most old bridges, the former had above its piers the usual nooks for the retreat of passengers, and few who remember it will not feel some regret at the change. ”

“ 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. ”

“ Beyond the towers workmen in great numbers deepened a fosse, heaped ramparts, strengthened walls, and in the earth over which Montmaure must advance planted sharpened stakes and all gins and snares that the inventive mind might devise. To hold this bridge was of an importance!—South and east stretched the yet unharried lands and the roads by which must come in food for the town, the roads by which it might keep in touch with the world without, the roads by which might travel succour! ”

“ Those gantries furnish us with an example of another sort of construction in wood which can be and is often used in bridging.
When the Germans retired in Northern France they blew up all bridges behind them, and before the Allies could use those bridges they had to repair them. If only for foot-traffic, a contrivance of poles, lashed together after the manner of the builder's scaffold, is ample in most of such cases and by its means a strong and safe bridge can be made upon what is left of the old bridge in the course of a few hours. ”