Engineering

An engineer by training, Eiffel founded and developed a company specializing in metal structural work, whose crowning achievement was the Eiffel Tower. He devoted the last thirty years of his life to his experimental research.

Born in Dijon in 1832, he graduated from the Ecole Centrale des Arts et Manufactures in 1855, the same year that Paris hosted the first world's Fair. He spent several years in the South West of France, where he supervized work on the great railway bridge in Bordeaux, and afterwards he set up in his own right in 1864 as a "constructor", that is, as a business specializing in metal structural work. His outstanding career as a constructor was marked by work on the Porto viaduct over the river Douro in 1876, the Garabit viaduct in 1884, Pest railway station in Hungary, the dome of the Nice observatory, and the ingenious structure of the Statue of Liberty. It culminated in 1889 with the Eiffel Tower.

Today, we meet the father and son who built the Brooklyn Bridge. The University of Houston's College of Engineering presents this series about the machines that make our civilization run, and the people whose ingenuity created them.

For me, the story of John Roebling begins in Kentucky, not far from where I used to live. On Sunday afternoons my wife and I would take our kids to see Old High Bridge over the Kentucky River. A plaque credits John Roebling with having started this old bridge in 1853. Actually, the bridge there today has been entirely reconceived. Still, the glorious spider web of steel emerging out of the quiet hilly isolation around it powerfully evokes Roebling's sense of design.

Squire and Anna lived in Utica, N.Y., where, as a well-known civil engineer, inventor, and theoretician, he developed the first scientifically based rules for bridge construction. After graduating from Union College in Schenectady, N.Y., in 1830, he did survey work for several railroads and canal projects and made surveying instruments. In 1840 he invented a lock to weight canal boats.

The invention of the steam engine required bridges which could support heavy live loads and this motivated Squire to turn his attention to bridges. At the start of the 18th century, iron as a structural material was unknown, but as the century evolved, cast iron came into general use and wrought iron was in commercial use by century end. He invented two new truss designs and in 1853 completed a 146-foot span iron railroad bridge near West Troy (now Watervliet), N.Y.

The first iron bridge was constructed in 1779 at Coalbrookdale, a cast-iron arch. Cast iron then began to replace stone, quite successfully in arch bridges, but the attempt to use cast-iron beams ended in the failure of Robert Stephenson's Dee Bridge. Thereafter, cast iron was used for compressive members only, and engineers turned to wrought iron as a tougher, more reliable material, using it first in massive tubular girders riveted together from the small plates which were all that were available at the time. Wrought-iron link chains were used for suspension bridges by Telford and Brunel.

In the United States, iron was expensive and largely imported from Britian because of the primitive state of the domestic iron industry. Wood, however, was abundant and cheap, and it was good hardwood that made an excellent material of construction. Wood, therefore, was the material most often used for even major bridges, with spans greater than 50 feet. We are not talking here of the trestles and king-post trusses used for minor bridges, but bridges that crossed the rivers and gorges that abounded. Two kinds of bridges were in common use, the lattice truss and the trussed arch, of which there were as many varieties as there were builders. Bridge builders were self-taught craftsmen and amateurs, for the most part.

The Berlin Iron Bridge Company was Connecticut's only large-scale fabricator of metal-truss bridges in the 19th century. Some 400 employees worked at its East Berlin plant, and hundreds of others worked in the field erecting the bridges. Over 1,000 Berlin bridges are believed to have been built before 1900. Most were in the Northeast, but even today Berlin bridges survive as far away as Texas. The company mostly built small-town highway bridges using its patented lenticular or parabolic truss. However, the Berlin Iron Bridge Company was prepared to take on any kind of fabrication work, including multiple-span city bridges, suspension bridges, drawbridges, and railroad bridges.

Hundreds of Berlin bridges were built in the company's home state of Connecticut. As of this date (August, 2001) only 13 highway bridges, 2 railroad bridges, and 2 millyard bridges are known to have survived.

The bridge maker’s signs advertised the builders of the wrought iron bridges that were popular at the turn of the century. These were collected in Central Illinois during 1968-70. There are over 180 signs represented under the “Maker’s Sign” icon. The bridge signs and the bridges they represent are under the major category icon “Iron Bridges”.

Addressing the shortcomings of the Burr truss, namely its expense and specialized labor, Ithiel Town patented his lattice truss design in 1820. The lattice design fastened simple, diagonally set planks with treenails, or wooden pins, into crisscrossing truss system secured by top and bottom chords. Thus, Town's truss eliminated the need for large and expensive timbers, used in the Burr truss' series of arches, and streamlined the intricate, time-intensive labor of fastenig mortice-and-tenon joints into the simple slotting and wedging of treenails. Town's innovative truss design is visible today in two of Connecticut's three remaining covered bridges, Bull's Bridge in Kent and West Cornwall Bridge in Cornwall and Sharon.

When the retreating French Army and its allies reached the banks of the ice-filled Berezina River on the 23rd of November, 1812, they discovered their sole means of escape blocked by the smoldering ruins of the Borisov bridge. On the opposite bank lay a Russian force under Admiral Pavel Vasil'evich Chichagov, sent there specifically to cut off the French retreat from Russia. But with ingenuity born of desperation, French Engineer Jean-Baptiste Éblé and four hundred pontonniers managed to quietly build two new bridges using materials taken from nearby houses. Only days before this the French Army's Commander-in-Chief, Napoleon Bonaparte, had ordered all sixty boats of the army bridging train to be burned along with all other "nonessential" gear. General Éblé protested the decision at the time and discretely ordered two wagons of charcoal and six wagons of tools to be spared. He also assigned each of his men to carry a tool and some cramp irons. The Berezina bridges would be built using only these hand-tools, during the winter, for an army on the verge of disintegration.

Consists of the author's A work on bridge-building : consisting of two essays, the one elementary and general, the other giving original plans and practical details for iron and wooden bridges. Utica, N.Y. : H.H. Curtis, 1847, plus supplementary text, Notes in correction and explanation of the original text, and Central forces.

The first covered bridge in America crossed the Schuylkill at High Street, now Market Street -- a familiar enough spot to generations of Drexel and Penn students and faculty! It replaced a pontoon bridge, and for that reason it was called The Permanent Bridge. It was not originally planned as a wooden or covered bridge, but rather as a stone bridge. The abutments and piers had been begun in 1800 and were complete in 1804, when the decision was made to complete the Permanent Bridge as a wooden bridge. For this purpose, Thomas Palmer, a bridge architect, was brought from New England. Palmer's bridge was braced with three arches and multiple kingposts. The suggestion that it be covered came from Judge Richard Peters, president of the Permanent Bridge Company. Palmer supported it, expecting the bridge to last thirty, and perhaps even forty years, if covered. Owen Biddle, a Philadelphia architect and builder, did the woodwork and ornamentation that were to make the bridge a memorable Philadelphia landmark.