Bridge
3 of the 7 encyclopedias on this shelf carry an entry for Bridge. Both are reproduced below, so you can see where they agree and where they differ.
Collier's New Encyclopedia (1921)
a structure consisting of an arch or series of arches supporting a roadway above it, designed to unite two banks of a river or the two sides of an open space. A bridge is generally made of wood, iron, stone, steel, or of brick. The extreme supports rts of the arches at the two ends are called butments, or abutments; the solid parts between the arches, piers, and the fences on the sides of the road or pathway, parapets. Bridges are now of many kinds, the most usual varieties being the following: Suspension Bridges. are such in which the roadway is suspended from chains, links, cables or ropes, passing over piers or towers, fixed or anchored at their extremities. Another line of evolution had its origin in the principle of suspension. In the typical modern suspension bridge, when the weight of the roadway is known by the stress on the suspending links, the problem of statical equilibrium assumes the simplest form, and the conditions of strength and stability are steadily dematerial by hydraulic pressure before termined. But when there is a shifting or rolling load on the roadway, which is heavy in proportion to the weight of the bridge, as, for example, a railway train, the conditions are involved. When the train occupies, say, only one-half of the bridge, the chain is depressed on one side, and is raised on the other side. Thus an undulation is produced in the bridge, which, especially if the train be moving rapidly, may seriously disturb the equilibrium, and even endanger the stability of the bridge. Various combinations have been devised to overcome this difficulty. The simplest and probably the best course is to stiffen the roadway, so that the stress of the passing load may be distributed over a considerable length of chain. In this manner large railway bridges have been constructed, for example, the Roebling bridge (1855) over the Niagara, 21/ miles below the falls, having a span of 822 feet, and being 245 feet above the level of the stream. 685,000 The Brooklyn suspension bridge, 7,232,000 across the East River, between New 35,000 York and Brooklyn, opened in 1883, is 63,637,000 built of steel. It has a central span of 1,595½ feet, and two land spans of 930 feet each; making, with approaches, a total length of 5,989 feet, or about one mile and one furlong. The anchorage at each end is a solid cubical structure of stone, measuring 119 feet one way, by 132 feet the other, rising to a height of 90 feet above mark, weighing 60,000 tons each. The towers are 278 feet high. The weight of the whole structure suspended between the towers is nearly 7,000 tons. The stress of suspension is borne by four cables of 5,296 steel wires each, 154 inches in diameter. The foundations of the towers were laid by means of caissons and compressed air, at a level of about 80 feet below high water mark. The Manhattan Bridge (constructed 1901-1911) across the East River between New York and Brooklyn, has a river span of 1,470 feet and a shore span of 725. It is 132 feet wide. The Queens Queensboro bridge (1901-1909) over the East River, joining These bridges New York New and Long Island City, is 7,144 feet long and 90 feet wide. Cantilever Bridges. A cantilever is a bracket. It is a structure overhung from a fixed base. The bridge across the river Forth on the North British railway system is one of the largest 1 and most magnificent bridges in the world. The site of the bridge is at 2 Queensferry. At this place, the estuary of the Forth is divided by the island of Inchgarvie into two channels, whose depth, as much as 200 feet, precluded the construction of intermediate piers. Hence, two large spans of 1,700 feet each were adopted. Between these, the central pier is founded on the island midway across, and is known as Inchgarvie pier. There are two other main piers, shore piers, known respectively as the Fife pier and the Queensferry pier. Of these three piers respectively three double lattice work cantilevers like scalebeams , 1,360 feet, or a quarter of a mile in length, are poised in line, reaching toward each other, and connected at their extremities by ordinary girders 350 feet long, by which the two main spans are completed. The bridge consists of two main span of 1,700 feet, or nearly one -third of a mile each; two of 675 feet each, being the shore ends of the outer cantilevers; and 15 spans of spans with fixed continuous spans connecting them . The Queensboro bridge is of the cantilever type. The Quebec bridge, 640 feet long, which fell while in course of construction in 1907, and again in 1917, was completed in the latter year. the Willamette river has a draw span of The Spokane bridge over 521 feet, the largest in the world (1920). The (1916) has a span of 1,800 feet. Other Quebec cantilever-truss bridge notable cantilever bridges are across the Colorado river, at Red Rock, those Cal., and across the Mississippi river, at Memphis, Tenn. of arches are often built in places where Arch Bridge-Bridges in the shape a more artistic structure than a truss is desired . The High bridge and Washington bridge across the Harlem river in New York City are examples of this style of bridge. The High bridge was built to carry the Croton aqueduct across the Harlem river. It consists of 13 CANTILEVER BRIDGE 168 feet each. The total length of the viaduct, including piers, is 8,296 feet, or a little over 1½ miles, of which almost exactly one mile is covered by the great cantilevers . The clear headway under the center of the bridge is 152 feet at highwater , and the highest part of the bridge is 361 feet above the same level. Between the two main girders a double line of railway is carried on an internal viaduct supported by trestles and cross girders. The whole of the metal work of the superstructure is of Siemens steel. The way consists of heavy bridge rails laid on longitudinal sleepers bedded in four steel troughs, into which the wheels will drop in case of derailment, when they will run on the sleepers. In the piers there are about 120,000 cubic yards of masonry, and in the superstructure 44,500 tons of steel. There are several of these bridges in the United States, the first of any size being the Niagara cantilever, built in 1883. Its total length is 910 feet, and it is 295 feet above the surface of the river , with steel towers 130 feet high. The Hudson river bridge at Poughkeepsie, built in 1889, has a length of 6,767 feet and is built in five spans; the first, third and fifth being true cantilever 12-Vol. granite arches, the highest one being 116 feet above the river. The bridge, crossing the river and valley, is 1,460 feet long. The Washington bridge is situated a short distance N. of the High bridge and consists of nine a granite on the E. side, four of granite arches , three of on the W., and two central steel spans connecting them. The entire length of the bridge is 2,300 feet, and width, 80 feet; the central spans being each 510 feet long and 135 feet above high water. Another noted arch bridge is located at St. Louis, Mo. It has two spans of 497 feet and one of 515, with a total length, including abutments of 1,700 feet. It is a two story affair with a double rail- The Hell Gate bridge over the East road track below and a roadway above. River in New York City is 1,000 feet yet constructed. It was completed in in length , and is the largest arch bridge 1916. Bridges. - One of the best examples of American Quadrangular Girder American longspan iron-bridge construction is the bridge across the Kentucky river on the Cincinnati Southern railroad, noteworthy for its economical design and comparatively light weight. The iron work of the bridge is 1,138 feet II-Cyc in length, and it consists of three spans of 375 feet each. It crosses a limestone canon at a height of 280 feet above the bed of the stream. The piers are of stone to a height of 60 feet, to clear the highest recorded floods; and they are about 34 feet thick at the flood level. Above the stonework the piers are of iron. The truss or girder is rectangular in section, 37½ feet high, 18 feet wide, consisting of top and bottom pairs of PARKER TRUSS BALTIMORE TRUSS PENNSYLVANIA TRUSS WARREN TRUSS XXXXXX HOWE TRUSS XXXXXX LENTICULAR TRUSS "K" TRUSS TYPES OF BRIDGE TRUSSES booms, forming the corners, united by panels or frames at intervals of 18% feet longitudinally, stiffened and bound with diagonal tie rods. The booms each consist of flat plates placed vertically, riveted together. The piers consist of hollow pillars of plate iron riveted together in box form. The diagonal rods are pin connected, that is to say, they are connected to the framework with cylindrical pins, a form of connection much practiced in the United States. The bridge was completed in February, 1877. Lattice Girder Bridges. - The iron lattice bridge, so called from having sides constructed with cross bars, like lattice work, is the natural outcome of the tubular bridge for long spans, developing equal strength with considerable economy of material and labor. Lattice girders are now almost universally adopted for iron bridges for long spans. Movable Bridges. - Movable bridges are usually required in the neighborhood of rivers, docks, wharves, canals, and like situations for the passage sage of ships and boats. They are variously designed and adapted to particular situations, and may be classified as (1) bascules or drawbridges, (2) swing bridges, (3) traversing bridges, (4) lift bridges, (5) pontoon bridges. Bascules or Drawbridges. The bascule bridge is such as is raised by turning, in one piece or in two pieces, round one or two horizontal axes or hinges. For large dimensions it is convenient to construct the bridge in two halves, lifting from each side, and abutting together to the middle. A bridge of this sort has been built across the Thames at London and another for elevated railroad use across the Chicago canal. They are now comparatively common. The largest one of the type was completed over the Chicago river in 1919. Swing Bridges. --Swing bridges are by far the most commonly employed of movable bridges. The large rivers to be crossed in the United States have demanded swing bridges of great span, with excellent contrivances for minimizing friction and insuring steadiness when closed. The swing bridge over the Raritan, in New Jersey, allows two free passages, each 216 feet wide. The Kansas City bridge crosses two passages, each 160 feet wide. The total moving weight is 303 tons. The bridge is opened by steam power in about one and a half minutes, or by manual power in two minutes. Traversing Bridges. - Movable bridges, sometimes called telescope bridges, capable of being rolled horizontally backward, or in an oblique direction, are occasionally employed. The bridge across the Arun, near Arundel, on the South Coast railway, is 144 feet long. It is traversed on wheels, and acts as a sliding cantilever, the overhanging portion resting on the opposite abutment when in place. Lift Bridges. - A notable example is the one erected over the Surrey canal, which is lifted by the four corners; another over the Royal canal, Dublin. Pontoon Bridges. - Bridges of boats are made of boats laid over with planks, fastened across the stream by means of anchors or stakes. The bridge at Rouen is 300 yards long, paved with stone for the passage of carriages and horses. The so-called flying bridge is rather a ferry than a bridge of boats. The longest floating bridge in the world, probably, is the pontoon bridge across the river Hooghly, at Calcutta, ends. They are each of the great length of 160 feet, made of such considerable length in order to obviate pitching motion in rough weather. The roadway platform is of 3-inch planks of teakwood from Burma, forming a roadway 48 feet wide, with a footpath at each side 7 feet HELL GATE BRIDGE OVER EAST RIVER, NEW YORK designed and constructed by Sir Bradford Leslie. The bridge is 1,530 feet long between the abutments, and is carried on 14 pairs of pontoons, which are held in position by means of chain cables , 14 inches thick, and anchors weighing three tons each, laid on the up stream and down stream sides, 900 feet asunder. By wide. An opening 200 feet wide, for the passage of ships, is made by removing , when occasion requires, four of the pontoons with their superstructure, and sheering them clear of the opening . The floating bridge is connected with the shore at each end by adjusting ways hinged to the shore. ROLLING LIFT BRIDGE their great length, the cables afford the necessary spring pring to allow for the ordinary rise and fall of the river, the stress on each cable varying from 5 tons to 25 tons, according to the stage of the weather and of the tide, the maximum velocity of which is 6 miles an hour. The pontoons are rectangular iron boxes, having rounded bilges and wedge-shaped Military Bridges are temporary constructions to facilitate the passage of rivers by troops, to restore a broken arch, or cross a chasm of no very great width . Those over a river are either floating or fixed. The former are made of pontoons , boats, casks, rafts of timber, or anything that will give sufficient buoyancy ; and the latter of piles, trestles, or other timber work. Spars, ropes, and planks are used in a variety of ways for spanning narrow chasms. The pontoon bridge is the only one which is carried with an army. Heavy guns are better warped across on specially constructed rafts. A flying bridge is a boat or raft anchored by a long cable up stream, and carried across by the action of the current acting obliquely against its side, which should be kept at about an angle of 55° with the current. Of the rock formations called natural bridges, the most remarkable is the COC LARIMER BRIDGE, PITTSBURGH, PA.-A CONCRETE ARCH natural bridge over Cedar Creek, in Virginia, 125 miles W. of Richmond. The mass of siliceous limestone through which the little river passes is presumably all that remains of a once extensive stratum. The cavern or arch is 200 feet high and 60 feet wide. The solid rock walls are nearly perpendicular, and the crown of the arch is 40 feet thick. History of Bridges. - Bridges seem to have existed in China from a period of considerable antiquity. The word bridge does not occur in the Authorized Version of the Bible. Temporary bridges, for military purposes, were constructed before permanent structures for the convenience of the inhabitants were erected. The former were often of boats. Thus, Cyrus constructed such bridges about 536 B. C., Darius Hystaspes about 490, and Xerxes about 480 b. C. Bridges of stone or brick seem to have been first used by the Romans; there were none erected in Greece till after the Roman conquest. The first Roman bridge is said to have been one spanning the Tiber, between the Janiculum and the Aventine mountain, built by or under Ancus Martius. Now they are universal in properly civilized countries, though in countries of imperfect civilization even yet they are few. Following is a list of the notable bridges of the world: Pons Sublicus, across the Tiber at Rome, defended 507 b. c., by Horatius Cocles. Cæsar's bridge across the Rhine, a wooden trestle-work, built 55 b. c. Trajan's magnificent bridge over the Danube, 4,770 feet in length, built A. D. 115. London bridge. One existed at the end of the 10th century; one built of wood, Car 1014; a stone bridge, by Peter of Colechurch, begun 1176, was finished 1209. The new London bridge is constructed of granite, from the designs of L. Rennie; it was commenced in 1824 and completed in about seven years, at a cost of $7,290,000. The bridge at Burton, over the Trent, was formerly the longest bridge in England, being 1,545 feet. It is now partly removed. Built in the 12th century. The Bridge of the Holy Trinity, at Florence, Italy, was built in 1569. It is 322 feet long, constructed of white marble, and stands unrivaled as a work of art. The Rialto, at Venice, is said to have been built from the designs of Michael Angelo. It is a single marble arch, 98½ feet long, and was completed in 1591. The Bridge of Sighs, at Venice, over signs, which condemned prisoners were transported from the Hall of Judgment to the place of execution, was built in 1589. Brooklyn Bridge was commenced, under the direction of John A. Roebling, in 1870, and completed in about 13 years. Coalbrookdale bridge, England, was the first cast-iron bridge. It was built over the Severn in 1779. High bridge, New York, by which the Croton aqueduct is carried across Harlem river, is of granite throughout. Victoria bridge, which spans the St. Lawrence at Montreal, Canada. It is tubular and 9,194 feet, or nearly 2 miles, long. The massive tube through which the railway track is laid is 22 feet high and 16 feet wide. It was formally opened in 1860. こ トナー
Aiton's Encyclopedia (1910)
a construction by which a passage is secured across a body of water or an open space. The simplest bridge is a log or slab of stone with an end on either shore. The first step in advance is to lay two or more beams parallel and cover them with flooring. All bridges of this sort depend on the stiffness of the material and its ability to stand the strain of bending. A great many small bridges of the present day, floors, and flat roofs are of this sort. Another kind of bridge may be represented by a spider's thread by means of which the spinner crosses an open space. The ends are made fast to the opposite shores and the thread sustains the weight of the spider by reason of its tensile strength, or ability to stand the strain of a stretching force. The circular orb web of the spider seen in dewy meadows is a bridge of this sort. The natives of farther India bridge streams by means of long canes of rattan. The ancient Aztecs of Mexico and the Peruvians understood the art of bridging chasms by means of vines and cables. Some of the finest bridges in the world, as the Brooklyn Bridge, the Suspension Bridge at Niagara Falls, and that at Menai Strait are suspended on wire cables of great tensile strength. A third sort of bridge is built of short pieces of material, disposed in the form of an arch. The strength of a well built arch depends on the ability of the material to withstand crushing. The Romans were the first to use material of this sort extensively in bridging. Bridges of stone and brick are common in all civilized countries. Before the introduction of iron construction, the bridges of cities and important roadways were built on arches. The bridges over the Seine in Paris and the famous London Bridge are of this description. Roman aqueducts and military roads were laid over arched bridges. If we add the ability to resist pressure from the ends, ability to resist doubling-up force such as is possessed by braces, piling, or the legs of a chair, we have the four kinds of strength utilized by the modern bridge builder. The iron pillars that support warehouse floors and the wooden trestlework of railroad bridges afford examples of material resisting a stress of this sort. The truss is an admirable invention. It is a frame designed to take the place of the beam required in the first kind of bridge described, or of the arch of masonry. By a very simple but shrewdly devised plan, light beams, braces, and tierods are so combined that when the ends of the truss are supported it cannot bend without pulling the tie rods in two. A truss is much lighter and less expensive than a beam of equal strength. Iron trusses longer than any possible beam are entirely practicable and are able to sustain enormous loads. The cantalever bridge consists of two balanced trusses approaching each other from opposite shores or piers, like the branches of two trees reaching out from opposite sides of a walk. When the trusses have grown out far enough to meet, they are bolted together. The Romans were the great bridge builders of antiquity. Their first bridges were of wood. A stone bridge was built over the Tiber about 127 B. C. The Emperor Trajan built a bridge over the Danube forty-six feet above the water. The first stone bridge of which we have any record in England was built near' Stratford in 1087. The first stone London bridge was built in 1176. An iron bridge was thrown over the Severn in 1776. It had a 100 foot span and 45 foot rise. Iron is now the prevailing material. The longest bridge in the world is said to be one crossing the Danube, having a length of 12,705 feet. There is a very long bridge across Galveston Bay, Texas. Brooklyn Bridge is said to be the ninth in length. The highest bridge in the United States is a railroad bridge crossing the Pecos River, Texas. It is 321 feet high. The highest bridge in the world is a new cantalever bridge crossing the gorge of the Zambezi River at Victoria Falls , South Africa. It is 650 feet long and 420 feet in height. A fine cantalever steel bridge crosses the River St. Lawrence six miles above Quebec. It has a span of 1,800 feet. It is high enough to clear the tallest ship. The so-called tubular bridges require mention. They are enormous wrought iron tubes, so large that railroad tracks may be laid within them. A bridge of this sort crosses the Menai Strait, Wales; another crosses the St. Lawrence at Montreal. In calculating the required strength of a bridge, builders find it necessary to allow quite as much for wind as for the weight of the bridge itself and that of passing trains. A bridge across the Tay, near Dundee, Scotland, was 10,780 feet long. It was considered the most remarkable bridge in the world. It blew down in a hurricane in 1879. See Arch ; Architecture 2026 Editor's Note: Bridge-building learned its hardest lesson in 1940, when the Tacoma Narrows Bridge twisted itself apart in a moderate wind before newsreel cameras — a failure of aerodynamics, not strength, that changed how every long span has been designed since. The longest now leap over a mile in a single suspended span. (Ed: BR 2026-07-09)
American Watchmaker and Jeweler (1892)
The standard secured to the plate, by means of screws, and in which a pivot works.