d iv 
 
 f 1868 
 
 
 
 1886. ? 
 
 JRON piGHWAY ^RIDGES, 
 
 AS BUILT BY THE 
 
 E’EN^^ 
 
 ] 
 
 Rridge 
 
 @PANY, 
 
 b:e]-z^’\7’e:ee zf^XjLS. 
 
 
 ^c. 
 
 Eastern A^ent, 
 
 .T« TltlBUSE BUILDIMi, | 
 
 NEW YORK. A 
 
 - ■ 
 
Digitized bS^‘^tHid“ffrtirnet Archive 
 in 2017 with funding from 
 Columbia University Libraries 
 
 https://archive.org/details/ironhighwaybridgOOpenn 
 
The Penn Bridge Company 
 
 locviver- lYM.'y, l'’;i 
 
 ENGINEERS AND MANUFACTURERS, 
 
 CONTRACT FOR 
 
 Wrought 
 
 Jr^on, Steel and Pombination Bridges, 
 
 IRON SUB-STRUCTURES, 
 
 Building’S, Roof JTrusses, Plate, Box^and Lattice Girders, 
 
 
 Architectural Iron Work Generally, 
 
To The Public. 
 
 TT7E wish to extend our tliauks to our friends and patrons for the cordial welcome which was extended to the first editi<m of 
 ¥ T our illustrated pamphlet. Some additional illustrations have been added in this edition, which will, we trust, make it of 
 / still more interest to you. We wish to add something to the general fund of information possessed lyv those who have 
 charge of the letting of Bridge Contracts, and to aid them in instituting a fair comparison between different j)lans submitted, so 
 that those which have the greatest merit, if presented by a Company having a good reputation for fair dealing and good, honest 
 work, may have the preference to which they should he entitled. We make no claim that we are the only Ifridge Company that 
 can or does do good work ; but we feel confident that our many patrons will bear us out in the statement that we always en- 
 deavor to faithfully perform our contracts, and to keep in the front in the march of improvement. Few persons realize how vast 
 has been the imiu'ovement in Iron Bridge construction; how much of it has been accomplished within a comj)aratively short 
 period, and how long is the list of names of the pioneers and promoters of this great industry. Ft may not be amiss, in this con- 
 nection, to append a brief sketch, giving a few points, some of which may be new to our readers. 
 
 IRON BRIDGE CONSTRUCTION. 
 
 The earliest bridge, in the construction of which iron formed the principal part, was, if we may believe Kirchen, in his 
 “China Illustrated,” a product of the civilization of the great Oriental Empire in the days of anticpiity, prior to the Christian 
 Era, in the form of a Suspension Bridge composed of chains, on which the floor was directly laid, following, consequently, the 
 curvature of the suspended chains. 
 
 c 
 
 ri’:- r 
 
We liave no further record of tlie use of iron in bridge construction until a long time afterward, about the close of the last 
 I century, when cast iron was employed, instead of stone, in the construction of an arch bridge of one hundred feet span, at Cole- 
 brookdale, England. It has, however, remained for the present century to develop the highly perfected forms of wrought iron 
 and steel bridges which we now have. Of these, the enormously heavy tubular bridges across Menai Strait and the St. Lawrence 
 are amongst the principal precursors, on the one hand as to the material, and the simple skeleton structures of Whi|)ple, on the 
 other hand as to the tyj)e, to which the more elastic and trustworthy material has been adapted, replacing tbe crude unreliable 
 cast iron which so largely entered into the earlier bridges of this form. Post, Fink, Warren, Bollman and others introduced 
 various forms of skeleton structures as distinguished from the solid tubular girders and heavy lattice trusses; and these all have 
 been modified in form and improved on in details by Latrobe, Murphy, Linville, C. Shaler Smith, Cofrode, Wilson-, and like in- 
 genious men; while Wood, Shreve, Merriman and Burr, have, through complete and elaborate investigations, jdaced such form- 
 ulas in the hands of the engineer as to enable him to disj^ense with much of the drudgery and tedious courses of experiments on 
 models, etc., which the earlier builders had to go through with, and to entirely do away with the “rule of thundi” methods 
 which were much in vogue among a certain class of highway bridge builders some fifteen or twenty years ago. We have said 
 nothing of the development of suspension bridges by Ellet and the illustrious Rmfiding, which has its greatest achievement in 
 the Brooklyn Bridge; as it is a peculiar and special type which has been shown to be only desirable in such long spans as are as 
 yet unusual in framed structures. A good illustration of this type, as designed and built by our Mr. Shipman, is however, shown 
 on page 24. The Niagara Cantilever Bridge bids fair to be the forerunner of a formidable competitor to suspension bridges for 
 long spans. Our wish is now, however, to trace out simply the development of that class of bridges winch is a universal want 
 of the civilized world for the common roads and highways of the people. Among the first iron highway bridges in this country 
 were the cast iron bow-string, commonly called arch, truss bridges, built by Whipple in eastern and central New York. The 
 arches were cast in straight segments of a circle, increasing in width from the center or top of the arch, to the skewback or base ; 
 they were very heavy, thereby making a well-braced, solid structure ; the lower chord, or string of the bow, was made of long 
 links of round iron formed just as the links of a chain are made, but of lengths equal to that of the panels of the bridge ; these 
 were connected by oval shaped cast iron bars or pins. Mr. Whipple also built a number of truss bridges of the type known by 
 his name, with cast iron upper chord and posts. These bridges, however, were expensive, and in the country west of New York 
 scarcely known and could hardly compete with such bridges as were built there of wood. This set the inventive genius of the 
 western country to work ; and some twenty or tw'enty-five years ago several styles of tubular arch or bow'-string bridges were in- 
 troduced, at such prices as to induce highway authorities to give them a trial : almost all these bridges, however, were built simply 
 
4 
 
 t(> sell, and although the materials from which they were made were of sufficient size so that they answered the purpose of a bridge 
 in most cases for a time, especially in shoi-t spans: yet they were generally constructed with so little regard to the principles of correct 
 bridge construction that there have been many failures of these bridges and their earlier competitors and successors. About 18G0, 
 IMr. T. B. White, the founder of our firm, an experienced builder of wooden bridges of the Howe and Burr truss styles, on tlie 
 earlier railroads (jf western Pennsylvania and Ohio, foreseeing that iron was destined to be the material of which the bridge of the 
 future was to be built, endeavored to elevate the standard of highway bridge construction, and introduced the Whipple style of bow- 
 string bridges, soon adapting, also, wrought iron to the arch meml)ers of the same; and there is no doubt that these are among 
 the best bridges now remaining of that cla.«s of structures; he also, knowing the acknowledged pre-eminence of the Howe truss 
 among wooden bridges, attempted to introduce it in iron as well ; but it did not prove to be an economical design in iron wlien 
 compared to the AVhipple truss and was soon abandoned, althougli a number of spans of about one hundred feet each are still 
 in j)ei'manent use and mark the progress of the science. It should always be remembered, however, that the correct j)rin- 
 ciples of bridge construction were but little known or understood at this time, and that “ rule of thumb” methods were the 
 rule and not the exception. Soon, however, influenced, no doubt by the fact that the active minds of men who had been engaged 
 in strife during the late war, were now diverted into ])eaceful channels, there were immense strides taken in the development of 
 correct mathematical jrrineijiles governing bridge construction, not only in general ])rinciples but also in those governing the 
 minutest details of construction ; and so far has this ])rogressed in the past twelve or fifteen years, that it may now lie said tliat, 
 with the majority of builders, more attention is paid and more skill displayed than in almost any other branch of mechanical 
 construction ; and this is the case, not only in railroad bridges, where Ave Avould naturally exj^ect to see it, beeau.se of the intelli- 
 gent supervision of their chief engineers and other officers, but competition has also made it progress fully as far in highway 
 bridge construction. For the benefit of those, however, who are called ujron to have charge of bridge work without the j)repar- 
 ation or technical knowledge which belong to the engineering branch of the j)rofession, it may be well to enunciate a few facts 
 and lay doAvn a few sound principles which they may follow. 
 
 The first thing to be considered in the building of a bridge at a given j^oint, is the number and length of the 6j)ans ; liere en- 
 ter in the questions of economy in first cost, and also that of safety to the Avhole structure by having the water way so little ob- 
 structed by the number of ])iers, that there shall be as little tendency as possible to form ice-gorges, or to affijrd lodging jdaces 
 for drift, which, by pounding or by sheer force of their weight, and the pressure of the v^’ater, may endanger the masonry. 
 All masonry, also, should be, where po.ssible, of large stone, well bonded together and thoroughly united by good cement, and 
 placed on a sure foundation. Where such a sub-structure is not available, the fewer the number of piers the better. To aid in 
 
5 
 
 ascertaining what length of span is the most economical, when safe, the following statement may be made: Supposing tliat for a 
 long structure no span less than eighty feet would likely ever be adopted; then if such a s])an, eighty feet long, would cost, sav 
 SIS per foot; for other spans the cost would be about in tlie following proportion; 
 
 Knowing, then, the amount of masonry rc(piired for eacli 
 different number of spans which may be suggested, the cost per 
 yard, and the probable cost of foundations, all of which can be 
 easily estimated by any one who has ever had anything to do 
 with charge of masonry, the most economical length of span may be figured out for any locality by the use of this table; this 
 being determined upon, the width of roadway is the next consideration; twelve feet in the clear between trusses, gives barely 
 enough space for the widest loads usually carried on wheels; and where room for pedestrians or horsemen to pass such loads is de- 
 sired, fourteen or sixteen feet may be adopted for a single roadway, usually so termed ; for a double roadway, admitting the 
 passage of vehicles in opposite directions, eighteen feet will answer for ordinary, and twenty-four feet for the widest loads. For 
 sidewalks, a^ least four feet shouhl be allowed for the passage of two persons in ojjposite directions, and for constant traflic, from 
 six to eight feet should be allowed that no one may be incommoded. In cities or large towns, it is often desirable (motives of 
 economy only, in general, preventing) to build bridges the full width of the street: when the location of such bridges will allow 
 of their being of the deck pattern it will usually be found economical that the trusses should be placed from sixteen to twenty 
 feet apart, with overhanging sidewalks. Another point should be considered in fixing the width of roadways, namely, the lateral 
 stifihess; for although bridges may be made sufficiently strong to re.<ist any wind pressure, having long sj)an and narrow nnul- 
 ways; yet for this consideration we should advise that bridges of ditierent lengths of span should have roailways not less than 
 given in accompanying table. 
 
 Next comes the determination of the strength re<purod. As a general rule bridges which are not 
 likely to be subjected to frecpient heavy loading may be lighter than those subjected to constant or 
 even frequent crossing; and bridges, which, by reason of constant crossing, are likely to be at times 
 nearly, or (juite cov’ered with loaded vehicles or large droves of cattle, should be rccpiired to be 
 stronger than those which are never likely to have more than a few head of cattle or two oi- three 
 teams on them at any one time. For these and like reasons we have made the divisions into classes which are shown in the table 
 of required strength on the seventh page. The use of this table, it should be remembered, must be governed by the judgment 
 of the person using it. Local conditions might require for instance, that a bridge, which the heading of the first-class would 
 
 Span. 
 
 Hoadway. 
 
 up to loO' 
 
 12 feet. 
 
 140 to 200' 
 
 14 “ 
 
 200 to 250' 
 
 1() “ 
 
 250 to 300' 
 
 1<S “ 
 
 Span. 
 
 Cost per 
 Lineal Foot. 
 
 Span. 
 
 Cost per 
 Lineal Foot. 
 
 Span. 
 
 Cost per 
 Lineal Foot. 
 
 30 feet. 
 100 “ 
 .120 “ 
 
 SLS.OO 
 
 20.00 
 
 22.50 
 
 140 feet. 
 IfiO “ 
 180 “ 
 
 S25.00 
 
 28.00 
 
 31.00 
 
 200 feet. 
 225 “ 
 250 “ 
 
 635.00 
 
 37.50 
 
 40.00 
 
6 
 
 2 )roperly describe, should be made of tlie strength given under the second, or even third class. We only mean to give a basis 
 which may be assumed as the minimum strength which should be required for bridges of certain g^ieral classes. 
 
 There are certain points in most bridges which are subjected to larger concentrated loads than those given by the table 
 would indicate; these are, the Hoor system — joist, beams and beam hangers, vertical suspenders, counter bracing and center 
 jDOsts; all these should be proportioned for as heavy a concentrated or local load as can be ascertained as used or likely to be 
 used in the vicinity. Among the heaviest pieces of machinery likely to be taken over any bridge are the road engines in use in 
 some parts of the country, which have a weight of eight tons on a wheel base of about eight feet by five. On roads where circuses 
 pass the weight of the largest elephant may be a point to be taken into consideration; their weights should be taken — with al- 
 lowance for impact — at six tons; the distance between the fore and hind feet being al)Out eight feet, from which the load on any 
 beam may be determined, and the proportion of the load may safely be assumed as in the exact center of beam or roadwa)'. 
 
 For bridges in cities where Aveling & Porter steam road rollers are used, their concentrated weight should be provided for: 
 the weight on front axles is about 14,000 tbs. in a width of fifty inches; the hind axle (the axles are about eleven feet on centers) 
 supports a weight of 22,000 fts.; wheels six feet, center to center. 
 
 In addition there may be a few points mentioned which should also be borne in mind as important ones in the selection and 
 construction of a bridge. 
 
 1st. The greater the capacity and conseejuent dead load of the bridge, the less will be the effect j)roduced on it by a rap- 
 idly moving load. In other words, a heavy bridge is stiffer than a light one. 
 
 2nd. It is important that all parts should be properly proportioned to meet the exact strains calculated to come upon tliem ; 
 for even if one or more members may have for example ten per cent, excess of material over that required, yet if any one mem- 
 ber has a deficiency of five per cent., the whole bridge might as well be deficient five per cent, as far as the carrying power is 
 concerned. A bridge is no stronger than its weakest member. 
 
 3rd. The quality of the iron should be well looked after. A good bridge iron will stand from 45,000 to 50,000 lbs. per 
 square inch ultimate strength; 21,000 to 20,000 lbs. elastic limit; and will have a good fiber and can be bent cold from 90° to 
 180° without fracture. 
 
 4th. The details; as the riveted connections, the bearings of pins, rivets and stirrups; the size of the pins as determined in 
 relation to their greatest bending moment, the lateral connections, the proper painting of the iron and protection of machined 
 surfaces before erection, are all points which can only be secured by the minutest specifications and the constant care of an expert 
 inspector, or else by the sedulous care of a company which exercises a jealous regard of its own reputation. 
 
7 
 
 5th. It is often the case that proper care is not taken of bridges after erection ; they should be examined occasionally to see 
 that dirt has not accumulated around the ends of trusses: -where there are any nuts in use they should be kej)t tight, and the iron 
 work painted sufficiently often to prevent rust. 
 
 Table Showing Live Load in Pounds per Square Fool of Roadway. 
 
 I>ENGTII 
 
 OF 
 
 Scans. 
 
 ! Couiury Bri<lges 
 
 not on Main Roads. 
 
 Bridges in Towns, 
 
 or Principal Roads in Country Between Towns 
 
 Bridges in Large Towns or Cities. 
 
 Bridges on Main Streets 
 
 1 in Largest Cities. 
 
 Roadway. 
 
 Roadway. 
 
 Roadway. 
 
 j Any Roadway. 
 
 12^ 
 
 14 ' 
 
 16 ' 
 
 18 ' 
 
 12' 
 
 14 ' 
 
 16 ' 
 
 18 ' 
 
 20' 
 
 22' 
 
 24 ' 
 
 16 ' 
 
 18 ' 
 
 20' 
 
 24 ' 
 
 30 ' 
 
 40 ' 
 
 60 ' 
 
 Under 6o' 
 
 100 
 
 TOO 
 
 TOO 
 
 TOO 
 
 125 
 
 125 
 
 I TO 
 
 1 10 
 
 I 00 
 
 TOO 
 
 TOO 
 
 150 
 
 150 
 
 150 
 
 150 
 
 125 
 
 125 
 
 ’25 
 
 ’ 5 ° 
 
 6o' to xoo' 
 
 TOO 
 
 TOO 
 
 90 
 
 90 
 
 T TO 
 
 r TO 
 
 TOO 
 
 TOO 
 
 TOO 
 
 90 
 
 90 
 
 125 
 
 '25 
 
 125 
 
 •25 
 
 >25 
 
 TOO 
 
 I 00 
 
 ' 5 ° 
 
 o 
 
 c 
 
 TOO 
 
 90 
 
 80 
 
 80 
 
 TOO 
 
 TOO 
 
 TOO 
 
 90 
 
 90 
 
 
 «5 
 
 125 
 
 125 
 
 125 
 
 125 
 
 •25 
 
 TOO 
 
 TOO 
 
 I 23 
 
 125 to 150 
 
 90 
 
 S5 
 
 75 
 
 75 
 
 TOO 
 
 100 
 
 90 
 
 80 
 
 80 
 
 75 
 
 75 
 
 125 
 
 125 
 
 125 
 
 I TO 
 
 1 10 
 
 TOO 
 
 90 
 
 '25 
 
 150' to 175' 
 
 , 85 
 
 80 
 
 75 
 
 70 
 
 
 90 
 
 80 
 
 75 
 
 75 
 
 70 
 
 65 
 
 I TO 
 
 I TO 
 
 I TO 
 
 I 00 
 
 TOO 
 
 90 
 
 80 
 
 -25 
 
 I 75' to 200' 
 
 
 75 
 
 70 
 
 65 
 
 
 
 75 
 
 70 
 
 70 
 
 65 
 
 60 
 
 
 T 10 
 
 I TO 
 
 TOO 
 
 90 
 
 80 
 
 80 
 
 ' 25 
 
 200' to 250' 
 
 
 
 60 
 
 55 
 
 
 
 
 65 
 
 65 
 
 60 
 
 55 
 
 
 
 TOO 
 
 90 
 
 80 
 
 70 
 
 70 
 
 1 I 00 
 
 250' to 300' 
 
 
 
 
 50 
 
 
 
 
 55 
 
 50 
 
 45 
 
 45 
 
 
 
 80 
 
 80 
 
 70 
 
 60 
 
 60 
 
 i too 
 
 Over 300' 
 
 1 
 
 
 
 
 
 
 
 
 45 
 
 40 
 
 40 
 
 
 
 
 70 
 
 60 
 
 50 
 
 50 
 
 1 00 
 
 With these loads the proper allowable strains on iron are: For princi])al tension members: 12,500 lbs. p(‘r sipuire inch ; 
 counters and suspenders — 10,000 lbs. per stjuare inch ; floor beam hangers — 9,000 lbs. ])er sipiare inch ; comj)rcssion meml)ers — 
 10,000 lbs. per scjuare inch ; reduced by Gordon’s or Rankin’s formulas. The load on sidewalks may be taken from 40 to 100 lbs. 
 per square foot, according to amount of travel. 
 
8 
 
 I 
 
 BRIDGE IN BERKS CO.. PA. .-200 Foot Span. 18 Foot Roadway. 
 
 BUILT BY THE PENN BRIBLE CD. 
 
THREE QEARTER DECK liRllXiE, HEAVER EAELS, 1*A. 
 
 
 Four Spans. 1 55 Feet Each. 20 Foot Roadway 
 
 BUILT BY THE PENN BRIDLE CD, 
 
10 
 
 DOUBLE INTERSECTION, WHIPPLE OR LINVILLE TRUSS BRIDGES. 
 
 Ou page 8 is a good illustration of a Doulile Intersection, Whipple 
 
 or Linville Truss Bridge. These bridges we erect for 
 
 spans of 140 feet and over. In addition to the span shown 
 
 we would mention the following 
 
 as a few of the many of this type 
 
 which we hav'e built. 
 
 
 
 
 
 Baltimore County, ^laryland. 
 
 One Span, 
 
 205 feet: 
 
 roadway. 
 
 20 feet. 
 
 Frederick County, ^Maryland. 
 
 One “ 
 
 125 “ 
 
 H 
 
 14 “ 
 
 New Brighton, Pennsylvania. 
 
 Two Spans, 
 
 200 “ 
 
 H 
 
 20 “ and one 5 foot walk. 
 
 Franklin County, Pennsylvania. 
 
 One Sjmn, 
 
 120 “ 
 
 n 
 
 10 “ 
 
 Allegheny County, Pennsylvania. 
 
 One “ 
 
 125 “ 
 
 a 
 
 17 “ 
 
 Warren County, Chio. 
 
 Two “ 
 
 150 “ 
 
 n 
 
 10 “ 
 
 Sandusky County, Ohio. 
 
 One Span, 
 
 140 “ 
 
 n 
 
 18 “ 
 
 Lake County, Ohio. 
 
 One “ 
 
 100 “ 
 
 
 10 “ 
 
 Fayette County, Ohio. 
 
 One “ 
 
 no “ 
 
 (( 
 
 18 “ 
 
 Lawrence County, Ohio. 
 
 One “ 
 
 132 “ 
 
 u 
 
 10 “ 
 
 Essex County, New York. 
 
 ( )ne “ 
 
 150 “ 
 
 n 
 
 14 “ 
 
 Panola County, Mississippi. 
 
 One “ 
 
 160 “ 
 
 <( 
 
 10 “ 
 
 Kewaskuiu, Wisconsin. 
 
 One “ 
 
 130 “ 
 
 n 
 
 10 “ 
 
 Galt, Illinois. 
 
 Two Spans, 
 
 140 “ 
 
 n 
 
 10 “ 
 
 Tyler County, West Virginia. 
 
 One “ 
 
 140 “ 
 
 n 
 
 10 “ 
 
 Culpepper and Fauquier Cos., Va. 
 
 One “ 
 
 150 “ 
 
 il 
 
 12 “ 
 
 On page 9 is shown a peculiar type of bridge, styled three quarter 
 
 deck, the 
 
 floor being raised in the truss, or rather the 
 
 truss put mostly below floor for the purpose of saving masonry. 
 
 
 
 
SINGLE INTERSECTION, WHIPPLE OR PRATT HIGH TRUSS. 
 
 11 
 
 liridges are 
 
 The cuts ou opposite pages 12 and 13 represent Single Intersection, 'Whipple or Pratt High Trusses. These 
 adapted to spans of from eighty to two hundred feet, and are likely used more than any other style of Truss. In addition to 
 the bridges at the locations shown in the engravings, we would name the following points as a portion of the many where we have 
 erected this style : 
 
 City of IMilwaukee, Wis. 
 
 La Valle, Wisconsin. 
 
 Two Rivers, Wisconsin. 
 
 Butler County, Iowa. 
 
 Peru, Illinois. 
 
 Wayne County, Indiana. 
 
 Grenada, Mississippi. 
 
 Flint, Michigan. 
 
 Eagle, Michigan. 
 
 Conway, Massachusetts. 
 
 Limestone County, Alabama. 
 
 Mercer County, New Jersey. 
 
 Frederick County, Maryland. 
 
 Cecil County, Maryland. 
 
 Tyler County, West Virginia. 
 
 Giles County, Tenn. 
 
 Collins County, Texas. 
 
 Sherman, Texas. 
 
 Co'bke County, Texas. 
 
 Travis County, Texas. 
 
 Cleveland County, North Carolina. 
 
 Mason and Cabell Counties, West Virginia. 
 
 Erie County, New York. 
 
 Chatauqua County, New York. 
 
 Red House, New York. 
 
 Newburgh, New York. 
 
 Columbiana County, Ohio. 
 
 Lawrence County, Ohio. 
 
 Butler County, Ohio. 
 
 Pickaway County, Ohio. 
 
 Jeherson County, Ohio. 
 
 IMiarni County, Ohio. 
 
 Carroll County, Ohio. 
 
 IMercer County, Pennsylvania. 
 Washington County, Pennsylvania. 
 Westmoreland County, Pennsylvania. 
 Montgomery County, Pennsylvania. 
 Lawrence County, Pennsylvania. 
 Luzerne County, Pennsylvania. 
 Butler County, Pennsylvania. 
 
 Elk County, Pennsylvania. 
 
 Bridgewater, Penn’a, | ^ 200^ 
 
 160 ' t 
 
 Treichler’s, Lehigh County, Pennsylvania. 
 
 20 ft. Roadway and one 
 5 ft. walk. 
 
12 
 
 BRIDGE AT SMITH'S FERRY. PA.— Span of 238 Feet. 16 Foot Roadway. 
 
 BUILT BY THE PENN BBTDG-E CD. 
 
13 
 
 BRIDGE AT NEW GALILEE. PENN.-130 Foot Span. 16 Foot Roadway 
 
 BUILT BY THE PENN BRI i EE CD, 
 
DETAILS OF HIGH TRUSS BRIDGES. 
 
 I At A and B are sliown ditfercnt designs of hip connections for high truss bridges, and are both good details ; that at A 
 
 ! however, giving the nearest approach we think practicable to a scpiare or tlat bearing. At C and E are elevations of shoes ; 
 
 I that at E is the more usual, while that at C gives probably a more evenly distributed pressure of the shoe on the masonry. We 
 
 have shown on the cross section of shoe at D, a stiff lateral connection made of angle bar; while that at F shows the ordinary 
 'i adjustable lateral connection made of round iron with a flattened eye; the detail shown on elevation of connection of the lateral 
 
 to shoe is also used on U2)i)er chord and floor beams ; other lateral connections for upper chord are shown in the sections at 
 
 G, and Q, and for beams at H, P and R. Beams are shown above the chord at H, and suspended at P and R. The posts, 
 
 , we almost always use of two channel bars latticed as shown in section at O; and details in connection with side view of ujijier 
 
 I chord made of built channel at I; side elevation of post, at center, for double intersection bridge at K, and side view of lower 
 
 chord at L: also in connection with cross section of upper chord at G, and (^; and cross sections of lower chord at H, P and 
 
 R. Knee braces are shown at intermediate posts in details I and ]\I. End elevations with portal bracing and cross .sections 
 with and without lower struts, diflering for different heights of tfuss are shown at T and l^. 
 
 I 
 
 I 
 
PEW BKIIXJE CO., BEAVEK FALLS, PA. 
 
SIDE ELEVATION OF LOW TRUSS BRIDGES. 
 
 On page 16 are represented several styles of low truss bridges of our manufacture. Tlie first is tlie ordinary Whipi)le 
 Truss; these we built with Latticed Suspenders, to aid in bracing the Truss sidewi.se; the second is a modification of the first in 
 the inclination of the End Post; the third is the Warren Truss, and is a very economical construction for Low Truss Bridges, 
 and as we have made them, have given veiy great satisfaction. The inclination of the end post, it will be noticed, is about the 
 same as in the second style usually termed “Low Truss” with half battered End Post. Of the Hub Plank or (luard, we show 
 three styles?, viz;. Plank, Iron Lattice and Gas Pipe; either of these can be used on any style of tru.ss, according to choice and cost. 
 
 We have Low Truss Bridges in considerable numbers in almost every State east of the Missouri River. 
 
 DETAILS OF LOW TRUSS BRIDGES, SHOWN ON PAGE 17. 
 
 ♦♦♦ 
 
 At A, is shown detail of construction at hi]) of middle or lower style of bridge on page Hi. At B is the detail of similar 
 connection in the first style on same page. I and K rej)resent the Shoe of any of these Bridges. C and L shows side elevation, 
 and I) and M Cross Section at same point for a Low Whipijle Truss with suspended built floor beam and channel iron post; at 
 S is shown an isometrical view of the same lower chord connection for bridge with sidewalk and handrail ; at R the same, with 
 solid rolled I floor beam and joists. 
 
 At E and N are shown side elevations, and at E and O cross sections at the same j)oints of upper and lower chords of a low, 
 Whipple Truss Bridge, with angle iron posts, and built beam placed above lower chord ; an isometrical view of same is shown at Q. 
 
 G, H and P show similar details of the Warren Truss. 
 
BRIDGE AT CITY OF RAHWAY, NEW JERSEY. 
 
 On page ‘20 is an extreme case of a low truss l)ri(lge, erected by us in the City of Uahway, New Jersey. The span is 110 
 feet with one roadway 36 feet wide in the clear, and two sidewalks each 10 feet wide in the clear, being the longest span and 
 widest single roadway of any low truss which we know of having been built. 
 
 On page 21 is shown an ordinary low truss bridge of nO feet span. 
 
MONROE STREET BRIDGE. — Built by the Penn Bridge Co 
 
21 
 
 BRIDGE AT PEEKSKILL, N Y.-Span 53 Feet. 14 Foot Roadway 
 BUILT BY THE PENN BRIE EE CD, 
 
22 
 
 ri:\.\' Hiiiixn: co., heavp:k falls, fa. 
 
 J 
 
 
 
 
 -\ 
 
 
 
23 
 
 DRAW BRIDGES. 
 
 In draw bridges, is required the most accurate workmanship of any class of l)ridge work, as, in addition to their being re- 
 quired to sustain loads under different conditions, ease in turning the bridge can only be maintained by having insured good 
 work when the bridge is new. In addition to the style shown, we also manufacture almost all styles of trusses, both high and 
 low, with parallel chords, for the same purpose. 
 
 We would name the following draw-bridges as having been lately built by us. 
 
 Span, 140 feet; 18 feet roadway and two 5 feet sidewalks: Milwaukee, Wisconsin. 
 
 “ lot) “ 18 “ “ “ two 7 “ “ Milwaukee, Wisconsin. 
 
 “ 120 “ 22 “ “ “ two f) “ “ Railway, New Jersey. 
 
 “ 120 “ 12 “ “ Noxubee County, l\li.ssissipjii. 
 
 “ 100 “ 1() “ ‘‘ Shebovgan, Wi.sconsin. 
 
24 
 
 SUSPENSION BRIDGE AT FRANKLIN. OHIO.— Single Span of 365 Feet. 20 Foot Roadway 
 
 BUILT BY J. W, SHIPMAN, ENBINEER, 
 
SUSPENSION BRIDGES, 
 
 (^f which an excellent example is shown on the op])osite {tage, are best adajjted of any style for long spans; say from 300 
 to 1000 feet. When properly constructed these bridges cannot be excelled, and have stood the test of long-continued use. Their 
 economy in cost is greatest, when, for shorter spans, it would recpiire numerous and expensive foundations. This department is 
 in charge of ourPIastern agent, J. W. Shiimian, C. E., who has devoted to it many years of study. The following successful 
 examples, of his construction, attest the value of his experience : 
 
 Bridge at Harrison, Ohio. 
 
 “ “ Linwood, Ohio. 
 
 “ “ Turner’s Falls, Mass. 
 
 Foot “ “ Delaware, Ohio. 
 
 “ “ Charleston, W. Va. 
 
 “ “ Windsor Locks, Conn. 
 
 Single Span of 420 feet by 18 foot roadway. 
 
 “ “ “ ddO “ “ 20 “ 
 
 “ “ “ o^{) “ “ “20 “ 
 
 “ “ “ “200 “ “ (5 “ 
 
 “ “ “ 2S0 “ “18 “ 
 
 Center Span of 550 feet and two approach s])ans ol’ 300 feet each, 
 by 20 foot roadway. 
 
26 
 
 TUBULAR PILRS 
 
 — riLLElO WITH — 
 
 PILES <5 concrete: 
 
 V 
 
IRON SUB-STRUCTURES. 
 
 We are jtrepared to build any kind of iron sub-strnctnre^ in localities where masonry is not available, or where tlnyv can 
 be built nuich cheaper than stone work. 
 
 The styles most commonly used by us are shown on opposite page. 
 
2y . COLUMBIA UNIVEPCirf " ‘ ^ “ [ 
 
 In additiun to the styles of trusses illustratetl in this painpldet, we are prepared to build all styles of Deck Arches, Canti- I 
 levers, and all styles of Trusses having upper chords more or less inclined. 
 
 \>'e also build Combination Bridges with u])pir chords and posts of wood; or with wooden chords and iron posts; the details ! 
 of these bridges are made hrst-class in every particular. At the date of issuing this catalogue, however, the price of all iron 
 bridges is so low that but very few combination bridges are called for. 
 
 W e trust that no one at the present day is deterred frotn building iron bridges in the place of wood by the difference in the cost, 
 as it is now very slight for bridges of equal cajiacity; and with the growing scarcity of timber, it is likely by the time a wooden 
 bridge would l)e worn out that it could not be rejilaced with wood for any less than iron. Therefore, build iron now. We are i 
 
 glad to quote jirices at any time. In writing for prices, please give us as much of the following information as possible: nuin- j 
 
 her and length of sj)ans ; width of roadways and number and width of foot walks; name of nearest Railroad Station and its 
 distance from bridge site; depth of water at low and high stages, and height of flcjor above water; what class the bridge would I 
 
 come under in our table, and whether in your judgment any stronger bridge is reijuired. 
 
 The Penn Bridge Works were first established in in a small way, and have grown since — so that in the past three 
 
 years the amount of work turned out amounted to 20,000 lineal feet of single track iron bridges. The total amount built by 
 these works since their start will amount to over ten miles. I 
 
 Two main lines of railroads (on which we have our own siding) passthrough our town, the I’ittsburgh, Ft. Wayne A Chicago 
 Railroad (Pennsylvania system) and the Jbttsburgh A Lake Erie Railroad (Vanderbilt system;. Our works are easily accessi- 
 ble to visitors, whom we always welcome and are glad to show through our establishment and over several fine bridges in the 
 immediate vicinity; they are also admirably situated for convenient access to the principal iron markets of the country, and 
 having natural gas and other special advantages for manufacturing and shipping to all points; in addition to the railroads 
 named, the Ohio River being only three miles distant. 
 
 Among other manufactories of the Beaver Valley, lying within a range of five miles uji and down the river, are large Iron, 
 Steel, Wire, Rivet, Cutlery, File, Axe and Saw Works, several Glass Works of various branches, and numerous Potteries and ! 
 Brick Works. j 
 
 We hope to hear from you when you have any bridges to let or in contemplation, and all business intrusted to us will have 
 prompt and careful attention. 
 
 Re-sj)ectJ'ully, 
 
 PENN BRIDGE CO. . 
 
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BRIDGE AT FLIXT, MICHIGAN. 
 
 Span of 130 Feet. Two 16 Ft. Pvoadways. Two 8 Ft. Sidewalks.