he Boston and Worcester Railroad, span across the Quaboad one of the first railroads built in River at Warren, just west , was chartered in 1831 of Spencer. It was success- Historic and opened to Worcester in 1835. This ful, and they gave Howe Twas followed by the Western Railroad, which the contract to build a would begin in Worcester and run to the New much longer at Structures York State line, connecting with the Hudson and Springfield. Berkshire line that ran to Albany, , on Howe received a patent, significant structures of the past the Hudson River. The latter line was completed #1,711, on a bridge . in 1838. The Western Railroad reached the east- on August 3, 1840 while he was building the erly shore of the River at Springfield Bridge. It had braces and coun- on October 1, 1839. The line of the Western ter braces crossing two panels, with additional Railroad from W. Springfield to the New York braces at the ends and additional longitudinal State over the lower Berkshire Mountains was member just below mid height. Long claimed completed on May 4, 1841. To make the con- that it was a violation of his patent rights, but nection across the Connecticut River required was unsuccessful in convincing the Patent Office ® a long bridge. Up to this time, most wooden they had erred in granting the patent to Howe. were constructed to the design of Stephen Howe wrote, “The -frame which I am about H. Long and by Ethiel Town. On the western to describe is in many respects similar to the segment, many bridges were stone arches. truss-frame for which, under several modifica- Other early wooden railroad bridges were by tions thereof, Letters Patent of the Lewis Wernwag over the Monocacy River and are about Copyrightto be granted to Harper’s Ferry over the Potomac River for the B me, under an application & O Railroad (STRUCTURE, August 2014). therefor dated the elev- Burr’s Trenton Bridge (STRUCTURE, June enth day of May, 1840; Springfield Bridge for 2014) across the Delaware was retrofitted for but it differs therefrom in Western Railroad railroad service in 1835 and Moncure Robinson the effecting of the strain- built several long Town Lattice for the ing up, and cambering, by Philadelphia & Reading Railroad as well as the the operation of iron bars, or rods, furnished with First Railroad Bridge Richmond & Petersburg Railroad in Virginia. screw nuts, and of wedge pieces so placed as to across the Connecticut (STRUCTURE, October 2014) be rendered effective by the action of said screw The engineers for the Connecticut River crossing rods, or bolts.” He claimed in his patent “The River in Massachusetts were William Gibbs McNeil, George Washington magazinemanner in which I have combined the iron bolts, Whistler and William H. Swift,S who wereT all earlyR and theU wedge piecesC against T which U the braces RBy FrankE Griggs, Jr., Dist. graduates of the United States Military Academy and counter braces abut, so as to cooperate in M. ASCE, D. Eng., P.E., P.L.S. at West Point. They were planning on using Long increasing the camber to any desired extent, the Trusses by Stephen H. Long for the bridge until whole truss-frame being constructed and acting, William Howe came to them with a new plan substantially as herein set forth.” that he claimed was superior to the Long Truss. There is no record of a patent issued on May Howe was a millwright from Spencer, 11, 1840, but there is one, #1,685, dated July Dr. Griggs specializes in the Massachusetts, located about 8 miles west of 10, 1840 for a much more complex truss with a restoration of historic bridges, Worcester and on the line of the railroad. He supporting arch and no iron rods that he claimed having restored many 19th Century was one of the three inventive Howe bothers. could be adjusted by wedges, etc. On both patents, cast and wrought iron bridges. He His brother Elias invented the sewing machine he gives his address as Warren, Massachusetts. was formerly Director of Historic and brother Tyler the spring bed. A wooden carriage and wagon toll bridge had Bridge Programs for Clough, Howe designed many churches and meeting existed nearby, since 1805, with a length of 1,234 Harbour & Associates LLP in houses, some of which required long truss spans feet and a width of 30 feet. Howe’s design was Albany, NY, and is now an for the roof. They were all entirely of wood with for seven spans of 180 feet, for a total length of independent Consulting Engineer. the exception of some iron bolts. Long’s truss 1,260 feet with masonry piers. Dr. Griggs can be reached at was also entirely of wood. At an old church in Unlike many old bridges where information is [email protected]. Brookfield, he a truss of wood that was sag- lacking, a complete description of Howe’s Bridge ging and there was no way of adjusting the sag. He was published in The Journal of the Franklin got the idea of replacing the vertical wooden ten- Institute in May 1842 by Lewis M. Prevost, Jr., sion members with wrought iron rods that were C. E. He wrote in part, threaded on both ends, which made it possible to Each truss is formed of a system of main braces, adjust any sag in the truss. This was fully intuitive, A, A, A, seven inches square, of white pine, as Squire Whipple had not then published nor inclined from the piers towards the centre of even developed the method of analytical truss the span, abutting upon white oak shoulders, design. It is likely he tried this out on a roof for C, C, C, which are let into the chords D, D, a church in Warren. He then convinced Swift to a depth of two inches; and counter braces B, and Whistler to try his design on a short 70-foot B, B, of the same dimensions, inclined in the

STRUCTURE magazine 23 many Long Trusses had been and as the earlier Burr, Palmer and Wernwag bridges were. The bridge opened in October 1841, completing the line linking Boston with the West at the Hudson River. The trusses were covered, not roofed and painted with a whitewash; a layer of tin was placed on the flooring and painted black. The tin was to cut down on the possibil- ity of fire. The bridge was replaced in 1855. With the opening of the Springfield Bridge, the became the bridge truss of Howe patent. choice, given its stiffness, adjustability and lower cost, for many railroads around the coun- try. Whistler left the Western Railroad and contrary direction, passing between each eight inches, both measured from the top of went to Russia to build the Nikolayev Railroad pair of main braces and also abutting upon the upper to the bottom of the lower chord: in 1842, and built® many Howe Trusses on that the white oak shoulders. The upper and the roof and floor would of course contain line as well. Howe’s bridge became known lower chords are composed of planks form- the same quantity of timber in both cases, around the world, as technical journals of the ing, in all, six horizontal beams of seven by and has therefore not been included, being time spread the word about advantages of the ten inches each. The whole truss is firmly evidently unnecessary in a mere compara- style. Many were covered and roofed but some bound together by the iron rods E, E, E, tive estimate of the amount of in were not, and those generally had a life of 15 two inches in diameter, passing between the each; we must,Copyright however, observe that the years or less. The Foxburg, Bridge main and counter braces, and through the above described trusses upon Howe’s plan, for the B&O Railroad over the Allegheny white oak shoulders; having screws cut on contain the subjoined quantity of iron, – River was double decked and survived until their lower ends, and the lengths adjusted a material not used in the lattice bridges 1921, when a bridge replaced it. Most by means of burrs; these suspending rods act – viz: Approximate weight of iron in the Howe Trusses after the Springfield Bridge in lieu of the king and queen posts usually suspending rods and burrs of the two trusses were not double intersection and had cast iron employed, and sustain the lower chords, of one of Howe’s bridges, of 180 feet span, shoulders (shoes) to receive the braces rather on which the girders, F, repose. The spans 21,100 pounds. Approximate weight of than wooden ones. On August 28, 1846, he are 180 feet each, and the deflection of iron in the transverse top ties, 710 pounds. obtained another patent, #4,726, adding an the bridge in the middle of a span, during Total, 21,810 or nearly, nine and three- arch to his truss pattern. Many Howe Truss the passage of a locomotive and train, by quarter tons of wrought iron. bridges still exist and carry roadways and light careful measurement, was found to be only magazineThe usual cost of the superstructure of duty railroad traffic. a quarter of an inch. S T Rcovered Urailroad bridges,C uponT the planU WhatR Howe Ehad done was to introduce Some of the principal advantages of this above described, with long spans, and for a wrought iron rods for his vertical tension plan are that the stress comes upon the end single-track railway, inclusive of all materi- members, enabling bridge owners to keep the grain of the main and counter braces, and als, and of the workmanship, is about $22 camber in their bridges. Squire Whipple, in is in the direction of their length – con- per lineal foot of floor. his 1847 Treatise on Bridge Engineering, gave sequently there is not the same danger of In conclusion, the writer will add his the engineering profession the ability to design the settling which occurs in lattice bridges, conviction, that in bridges with spans each member of a truss to carry the load it in consequence of the crushing of the pins equal to, or exceeding, those of the bridge would see in service; this made it possible to and the splitting of the lattices at the ends at Springfield, the peculiar truss above vary the size of its members as necessary along and there being a free circulation of air described, will be found superior in the length of the truss. Howe’s brother-in-law, between the main and counter braces, the strength, stiffness, and durability, to those , built many Howe trusses in the bridge is not so liable to the speedy decay of Town’s double lattice plan. mid-west. On the 150-foot long Ashtabula which occurs in lattice bridges, wherever He added struts from the piers up to the Bridge, he replaced the top chord wooden the lattices come in contact. There is also first, second and third panel points, with an members with wrought iron I-beams and the less timber required in Howe’s truss than extra 9- by 12-inch bolster. His panel length lower chord with wrought iron rods making it in Town’s. was only 7 feet and, with a height of truss an all iron bridge. Unfortunately, the bridge For a bridge of 180 feet span, there of 18 feet, was a little flatter than the pre- collapsed on December 29, 1876 killing 90 are in Howe’s truss frames, 28,636 feet ferred 45°. He had wrought iron bars across people. In iron, the Pratt Truss over time board measure. the tops of the trusses for lateral stiffness. generally replaced the Howe Truss for both For a bridge of 180 feet span, there At the ends of his braces and counterbraces railroad and highway traffic. Howe, however, are in Town’s double lattice, 46,080 feet he had wooden shoes, white oak shoulders, was able to retire and live off the patent fees board measure. to transfer the diagonals loading to the top he charged for use of his patented truss.▪ These quantities of timber have been cal- and bottom chords. His braces and 2-inch culated for the trusses, or sustaining parts wrought iron bars were all the same size over This is the last in the series of notable only, of the two plans respectively; supposing the length of the truss as were the chords, so wooden bridges. In the next and following each to span 180 feet, and the truss depth it is obvious he did not fully understand the issues, Dr. Griggs will discuss the cast and of the former to be eighteen feet, whilst that loading in the members. The trusses were wrought iron bridges that were dominant of the latter was assumed at nineteen feet continuous over the piers in the same way between the 1840s and 1880s.

STRUCTURE magazine24 November 2014