An Unusual Application of Wire Cables from the 1850s: Benjamin

Construction History Volume 1 7 , 2001
An Unusual Application of Wire Cables from the 1850s:
Benjamin Severson's Wire-tied Iron Girders
SARA E. WERMIEL
Dawn of the structural use of iron in the United States
One of the most remarkable facts about the constructive use of iron in the Unlted States is how
suddenly it began Before the mid-1840s, practically no American strocture contained iron except
in minor ways e g ,in fasteners and tles Architects used iron columns m afew churches, theatres,
and market halls, and two fireproof bulldings with floors made of iron beams and bnck arches had
been constructed Engineers had put up a few all-iron bridges and towers (speclfically, two Iron
beacons and an iron-plate lighthouse) In the latter part of the decade, the use of iron for structural
purposes increased Between 1845-1849, architects and engineers e~ectedthe first cast uon
storefronts as well as several more iron bndges and the earliest iron skeleton lighthouses Then
came 1850-51, a watershed for structural iron use in the Umted States In the early 1850s, merchants'
demand for iron storefronts swelled, and the number of these erected grew from a handful to
dozens, the Baltimore & Ohlo Railroad made iron the standard matenal for its future bndges, U S
Army engineers had two uon skeleton lighthouses, 100+ feet (30 5+ meters) tall, under construction,
and the federal government specified that its new public bulldlngs have Iron internal frames. By
no means did iron displace cheap and versatile timber - still the most wldely used buildlng matenal,
and conventionally-bullt structures, with wood-frame or masonry walls and timber Internal
structures, greatly outnumbered those with structural frames of iron But the growth in Iron
production capacity at the furnaces during the 1840s, coupled in the early 1850s with weak demand
from the rail mills - a large consumer of Iron - meant that Iron was avalable for a variety of
projects where it had formerly been used spanngly Iron had qualities that made ~ta necessary, or
at least a cost effective, choice for certan applications, such as for long spanning members and to
support heavy loads Other qualities that recommended it over timber were its plasticity (ablhty to
be moulded), permanence, and noncombustibility
By the tlme Amencans began to use uon structurally in a large way, Bntish and French engineers
had been designing with it for about fifty years At first, the Europeans simply subshtuted Iron for
stone or wood, uslng forms denved from masonry and timber construction But they eventually
came to appreciate that iron performed differently than stone and timber, and this reahzation led to
a search for efficient and reliable forms for the new materlal In 1845, research connected with
trying to find the best form and material for girders for two long-span iron bridges in Great Britain
-the Britannia and Conway - illuminated the distinct mechanical characteristics of cast and wrought
iron Wrought iron, the expenmenters found, had supenor tensile strength, and therefore they
recommended ~tover cast iron for spanning applications However, by weight, wrought iron was
more expensive than cast iron.
This was a penod of much expenmentatlon with forms and matenals, in an effort to find effective
and economical solutions for particular structural problems Poor design of some early iron brldges
and building frames led to deadly collapses In Britaln and the United States ' Amencan engineers
drew on the experience of Europeans as well as theu own emplncal and theoretical work when
they designed in iron
Sara E. Wemiel
A n Unusual Application of Wire Cables from the 1850s:
Benjamin Severson's girders
hxl
F~gure1A Cast iron glrder m Farmers and
Glanopulos, Keast & Hood Co , Phladelphla,
P ~ M S Y ~ V1992
~ ~ )N ~ ,
Figure IB Detall of wire cable on Farmers and
Mechanics Bank girder. (Photo: Nicholas
Gianopulos, Keast & Hood Co., Phlladelph~a.
Pennsylvania, 1992.)
One American engineer-architect who tackled the question of the proper design of iron structures
for long spans and to support heavy loads was Benjamin Severson. His recently discovered surviving
work, along with the articles he wrote for technology periodicals, reveal a remarkably creative
engineer. He is also completely unknown. That his work and life have been brought to light at all
The most unusual aspect of his work was his use of wire cables
is due to fortuitous circumstan~es.~
to reinforce cast iron spanning members.
In 1981, during renovations of an old bank building in Philadelphia, Pennsylvania - the Farmers
and Mechanics Bank - engineers discovered four cast iron girders. The girders supported two
floors (two per floor) in rooms at the north end of the building. Each was a one-piece, reinforced,
arched truss, 30 feet (9.15 meters) in length. The large size and sophisticated design of the girders
at such an early date -they were made 1854 or 1855 -make them deserving ofnotice as important
engineering artifacts. But they also had a most unusual feature: the ties along the bottom, tying the
ends of the arch, were wire cables. Each girder had two cables, one on each side, made of parallel
wires completely wrapped in wire.3 (Figs. IA-1C.)
When they were made, the idea of reinforcing cast iron girders was not new, but had been
adapted from the practice of reinforcing timber beams with iron rods. One such iron truss commonly
used in Britain in the 1840s involved stretching an iron tie from the upper side of the ends of a
beam to saddles underneath to create a "trussed beam." (Fig. 2.) The Dee Bridge in Chester,
Figure 2 Tmssed girder, from Fairbairn. 1854 (William Fairbaim, On the Applrcntion of Cast and Wrought Imn to Building
Purposes (New York. 1854.)
which collapsed in 1847 after about half a year of service, was this type of truss. William Fairbairn
reported on tests of trussed beams in his important 1854 book On the Application of Cast and
Wrought Iron to Building Purposes and concluded that the wrought iron tie rods added little to
In the United States, a common sort-of reinforced cast iron girder was the "bowstring"
their ~trength.~
girder, which consisted of a cast iron arch tied across the bottom with a wrought iron rod. (Fig. 3.)
A contemporary wrote in 1851 that such girders were used "to a large extent." They typically
supported the walls of city stores above an open ground floor, permitting glazed storefronts and
wide doorway^.^
Figure 1C Cast iron girder In Farrners and klechaliics
Bank, Philadelphln, Pennsylvanla. Bearing end detail
and sectlon showing wide cable ties (Keast & Hood
C0.RI.A.E.R. 2001)
Truss Gwdcr, with Rod.
Figlire 3 Bowstring girder, from New York Wire Railing Works, 1855 (New York Wlre Railing Co., A New Phnse in Imn
Manufacture, New York, 1857.)
An Unusual Application of Wire Cables from the 1850s:
Severson's girder in the Farmers and Mechanics Bank was not like the British trussed beamlgirder
or the bowstring girders. Rather, it was a cast iron truss tied along the bottom chord. While there
were precedents for all elements of the design (i.e., trussed arches of timber for the general shape,
bowstring girders for the tied arch), no other iron girder of this form is known from this date. Moreover,
Severson not only designed the girder; he made it, too. J. A. Gendell & Co.'s Architectural Iron
Works in Philadelphia, which had recently been organized to manufacture structural iron for buildings,
manufactured the bank girders, as indicated by the foundry mark. Severson was the superintendent
of the f ~ u n d r y Making
.~
these large castings in a relatively complex shape was an accomplishment it
itself. That the girders survived in perfect condition until their removal after about 127 years, testifies
to Severson's abilities both as an engineer-architect and artisan.
The cables on these girders were no one-off project or a fluke, as Severson had already incorporated
wire cables in an iron truss bridge he designed some years before. In 1849, he exhibited a scale
model of his bridge at the annual fair of the American Institute in New York City. The following year,
a full-size example of the bridge was built by the important Schenectady, New York, foundry, Clute
Brothers Foundry and Machine Shop. As described in an article about it in Scientific American, the
bridge was made of connected cast (or wrought) iron panels or voussoirs that formed a cambered
span. Two wire cables, one on each side of the bridge, were fixed to the base of the end posts and ran
parallel with the bottom chord of the truss. The panels were joined at the top by a cap secured by a
nut on a threaded rod, and at the bottom by an outside bracket and beam that spanned between the
sides of the bridge and carried the bridge deck. Another unusual feature of the bridge - considering
its early date - were two diagonal "counter or quarter braces," as Severson called them, that stretched
from the top of the end posts to points on the bottom of the panels; these were designed to check the
horizontal pressure at the ends of the span. They could be made of wire cables or wrought iron rods.
The bridge held up well in a load test: a 72-foot long span was loaded with 42 tons of iron (three
times the total weight of the spanning part, not counting the end posts) and carried it for over a day
withont apparent overstress. Severson wrote that the design could be adapted for railroad bridges,
for spans up to 500 feet, by adding a wire cable, or wrought iron bar, to the top chord on each side of
the bridge. (Figs. 4 and 5.) Since wire cables were a relatively new thing, Severson included an
Figure 4 Severson railroad bridge. 1851 ("Severson's Iron Bridge,"Appleton's Mechanics'Magazine 2, 1852).
illustration of one, showing how it was wrapped around a "bow or staple-bolt" and could be drawn to
the proper tension by the tightening the nuts at the ends. (Fig. 6.) The Clute foundry was prepared to
take orders to make more of these hridges. 'This bridge," the editor of ScientijkAmerican commented,
"is exceedingly beautiful in design, as well as being strong and durable in its const~ction."~
In another article about his bridge, which appeared in 1852, Severson explained at greater length
how forces would act on the bridge and his reasoning for arranging the ties and braces as he had.
Interestingly, he justified placing the main cables in line with the sides of the bridge, rather than in a
straight line below the camber (as he said some men had suggested), in order to prevent vibration - to
hold down the bridge - as much as to strengthen it. A point forgotten by engineers in the early
Sara E . Wermiel
twentieth century, with one disastrous consequence, "it is as important to prevent any part (of the
bridge) from rising above its true position, as it is to prevent other parts from sinking below it." At
the end of this article, he listed the features of the design he considered new, as if for patent purposes;
l
Although no such bridge has been discovered,
yet, he did not patent this or any of his s t ~ c t u r adesigns.
or has even been noted in histories of bridge construction, Severson wrote he built "several" of them,
"and they continue to give satisfaction."' This would make Severson's hridges among the earliest
all-iron bridges in the United States.
Severson also tested his girders for bearing
strength. The first report of a test appeared
in the Jocrrnnl of the Franklin Institute in
1854. The girder tested was described as
being of cast iron, with an arched top and two
at the bottom; it measured
Figure 6 Parallel wire, wrapped cable, for Severson's bridges
34.55 feet (10.5 meters) for a %-foot clear
("Severson's Iron Bridge,"Appleronk Mechnnics'Magazine
2.1852).
span. It was designed to support a uniformly
distributed load of 20 tons. The report did
not include a drawing, so its exact form is unknown; moreover, the ties could have been either wrought
iron bars or wire cables. The test involved suspending a platform from the girder and loading it with
iron bars. When loaded with 52 tons, one of the piers holding an end of the girder broke. Although
the girder sagged at this load, it returned to its original shape when the load was removed, indicating
it had not suffered any permanent distortion? These girders went into a Philadelphia dry goods store
built for Fassitt & Co. The building was demolished years ago, so we can only wonder about the
details of their design.I0
Severson made his wire-tied girders again in 1859 to support the floor above an auditorium in the
new Peabody Institute building in Baltimore, Maryland. George Peabody, a wealthy ex-patriot
merchant living in London, wanted to establish an institution that would "expose the citizens of
Baltimore to the finest in literature, music, and the fine arts;" accordingly, the building for his Institute
was to contain a library, auditoriom, and art gallery. Construction began in 1858 hut was not complete
by 1861, when the Civil War stalled the work, and the building was not finally dedicated until after
Sara E . Wermiel
An Unusual Application of Wire Cables from the 1850s:
the war, in 1866. The Peabody Institute girders are a wonder of mid-nineteenth century American
engineering and it is regrettable that they are inaccessible today - covered by a ceiling and not
visible. However, their form is known from surviving architectural drawings and c o n f i e d by an
engineer who actually saw one of the girders in the 1980s when it was briefly exposed during
renovations of the auditorium.ll
Fabricated by the well-known Baltimore foundry Hayward, Bartlett & Company, the Peabody
girders measured 69 feet (21 meters) long and 45 inches (1.1 meters) deep in the middle of the arch,
and spanned 66 feet (20.1 meters) in the clear from wall to wall. (Fig. 7.) The auditorium measured
66 feet wide and 100 feet long, and the four girders were spaced about 20 feet center to center. Like
his earlier girders, Severson's Peabody girder was a cast iron truss with an arched top, but was made
of three sections bolted together. Wire cables ran along the bottom chord and tied the ends of the
arch. The girders supported a massive timber-framed floor: brackets, or bearers, cast on web pieces
of the truss carried wooden beams, which in turn camed 3 x 15-inch joists topped by a 3-inch-deep
plank floor. The total depth of this assembly, to the top of the plank floor; was 4 feet. The girders
supported the dead weight of the floor - 16,000 pounds per girder - and no doubt the great additional
load of a library on the second floor (the building has been renovated and the library and art gallery
no longer occupy this floor). Thus, they were not only long span, but they successfully camed a
substantial load.
Severson specified wire cables to tie the bottom chord of the girder: these were to be 2lh-inches
(6.35 cm) across, made of 218 strands of No. 10 wire. Charles Ellet, Jr. used wire this size for the
cables in his early suspension bridges, for example, the 1841 Callowhill Street bridge across the
Schuylkill River at Philadelphia - the first American wire suspension highway bridge - and later for
his long-span Wheeling, West Vuginia suspension bridge, completed in 1849.12 Specifications for
No. 10 wire, from the catalogue of a contemporary manufacturer of wire products, were as follows:13
Dlameter
No. 10 wlre gauge
0.140 in.
We~ghtof
100 yards
14.97 Ibs
Area of sectlon,
sq. ~nches
,016
Brealang
weight
1280 lbs.
If these figures were applicable to the Peabody cables - and this is a big "if," slnce several wlre
gauges were In use In the nineteenth century -each would have we~ghedabout 750 pounds (340 1
kg) Overall, each g~rderwe~ghednearly 20,000 pounds (9,070 3 kg)
Severson publlc~zedthe Peabody g~rderin Sczentzfic Amencan, where he reported on a load test
ordered by the Bulldmg Comm~ttee'sconsulting arch~tect After completing the hmber floor, the
arch~tecthad a bnck wall bullt In stages over one of the girders, ulhmately 150,000 pounds of bncks
were plled on the glrder, dlstnbuted evenly along ~ t length
s
Thls load deflected the g~rder
2'12 Inches from level, but ~treturned to level when the load was removed Severson noted that the
deflect~onwas less than that reported for other styles of guders, even under thls enormous load ' W e
wrote that guders of h s des~gnhad been made "of vanous lengths and capacity, for vanous purposes,
and all seem to anbwer equally well "I5
Desp~tethe publlc~tyh ~ deslgn
s
recelved In the techmcal press, and that h ~ girders
s
were made
at a large foundry where artlsans and engineers could see them, the Idea of uslng wlre cables In
trusses d ~ not
d catch on l6 Nor have other g~rdersof t h ~ sstyle turned up, although an Important
toundry - the Arch~tecturalIron Works of New York - advert~seda very s ~ m ~ lg~rder
ar
m ~ t 1865
s
catalogue (Fig 8 ) T h ~ sfoundry, superintended by the prominent Iron founder Daniel Badger,
Rgure 8 Glrder In Arch~tecturalhon Works ot the C ~ t yof New York, catalogue, 1865 (Badger's Illurrated Catalogrre of
Cast-IronArchrtecture, New York, 1981, plate 63)
Figure 7 Drawing of a girder for the Peabody Institute, Baltimore, 1859 (Archives of the Peabody Institute, nrch~tectural
drawings, photo by Sara Werrmel.)
had Invested tn Gendell's Phlladelphla foundry, also called Arch~tecturalIron Works Whlle the
two plants d~ssolvedthem assoclatlon at an early date (In 1855), they were together when Severson
worked for Gendell's firm and made the Farmers and Mechanics Bank guders The New York
verslon of the g~rdermost l~kelyhad wrought Iron bars rather than wlre tles, and the dlagonal parts
of the web slant In the opposlte dlrectlon from those of Severson's glrder
Why d ~ Severson
d
use wlre cables rather than the usual wrought uon bar t~es?One hint to Severson's
cho~ceIS suggested by h ~ ssteadfast advocacy of cast Iron for g~rdersat a tlme when "learned
ph~losoph~cal
wnters," such as Fauba~m,were advocating wrought Iron over cast Iron for beams A
seem~nglyfatal disadvantage of cast Iron for spannlng members was ~ t lack
s of tens~lestrength, and
thus the extra amount of metal requ~redto compensate for thls and the consequent large dead load
But Severson found that his g~rderswe~ghedless than wrought uon ones of equal strength des~gned
by F a ~ r b a ~ m
The attraction of wue was ~ t h~gher
s
strength-to-we~ghtratio compaed w ~ t hwrought
Iron bars, whlch would have saved we~ghtIn t h ~ element
s
The Farmers and Mechanics Bank wue
cable - one for whlch the we~ghtcan be compated - welghed about 5 poundslfoot Presumably, an
uon bar that performed as well as this cable would have we~ghedmore IS
A n Unusual Application of Wire Cables from the
1850s:
Severson's career
Where did Severson learn to design? What became of this talented engineer-architect?
Unfortunately, no information about his early life or education has turned up. Records of the 1850
federal census for Little Falls, New York - where he lived when he exhibited a model of his bridge at
the American Institute fair - reveal that he was 40 years old and employed as a pattern maker, no
doubt for a foundry. Thus, he was a mature man when he introduced his bridges. By 1851, he had
moved east to the bustling city of Schenectady, where the Clute Brothers' foundry made at least one
of his bridges. From there he moved on to Philadelphia and took the position of superintendent at J.
A. Gendell's newly established foundry, Architectural Iron Works, and where he made the Farmer
and Mechanics Bank girders in 1854 or 1855.19
Gendell's company apparently was not profitable, and perhaps for this reason, or for the opportunity
of working on a prominent construction project, Severson left Gendell and in September 1855 began
working as a construction foreman on the extension of the U.S. Capitol building in Washington, D.C.
Captain Montgomery C. Meigs of the Army Corps of Engineers, the superintending engineer on the
project, hired Severson on the recommendation of Stephen Colwell, an important Philadelphia-area
manufacturer of iron pipes. Severson was responsible for erecting the iron roofs over the new wings,
which involved raising and finishing the huge iron trusses and attaching iron panels that formed the
ceiling below them, as well as for putting up iron frames for the doors and windows. With the project
running far over budget, Meigs sought to economize by mechanizing aspects of production. He
hired Severson partly because of his experience using machines to move building materials and
thereby save labour costs.
But after only a year at the Capitol, Meigs discharged Severson on the grounds of neglect of duty,
although he told Severson the reason was lack of work. Severson apparently had run afoul of the
status-conscioos Meigs by trying to associate with the professional men working on the Capitol
project rather than the artisans exclusively. In his journal, Meigs complained Severson "has mistaken
his place, which is that of a foreman. He has not spent his time among the workmen and has been in
[Francis] Brooks' office.. .."?O This, describing a man who had designed some of the most sophisticated
iron structures in the country.
Meigs's journal, Severson's letters to Meigs, and letters from Colwell to Meigs concerning Severson,
give glimpses of Benjamin Severson's personality. He comes across as a self-assured man: confident
in his technical knowledge, jealous of his reputation for competence and integrity, and someone who
was not afraid to criticize what he considered the bad work of others, even the writings of William
Fairbairn. Colwell had warned Severson when he took the Capitol job not to be too assertive;
nevertheless, Severson made some enemies there. In reply to a letter from Meigs about his decision
to f i e Severson, Colwell wrote, "If Mr. S. had strictly followed my advice he could not have incurred
your displeasure. He has good qualities, perhaps some for which you would scarcely give him credit
now. . .. I am sorry for him but think he is to blame. He has some impractical points which seem to
be much in the way of his success in life."z1
Severson's self-assurance also comes through clearly in an essay he wrote in 1858, published in
Scientific American, about the merits of his style of "compound (tied-arch) girder compared with
wrought iron girders. After 1854, the year William Fairbairn's authoritative text on iron appeared
and when an American mill first began rolling solid, wrought iron beams, architects and engineers
became increasingly interested in using wrought iron for spanning applications. Severson believed
Fairbairn's rationale for favoring wrought iron over cast iron beams derived from faulty theory. His
own theory about the direction forces in a beam was unorthodox, but led him to conclude that a tied
arch girder was the most efficient form of beam. Moreover, using cast iron - since it cost less than
wrought - was the most economical choice.22He wrote this while he was living in Baltimore, and he
pot his ideas to the test in the design he made for the Peabody Institute girders.
Sara E. Wenniel
Severson also designed iron trusses for the roof of the Peabody Institute. For these, he used
wrought iron ties (three long wrought iron eye-bars on the lower chord of each). They spanned
the same length as the girders, 66 feet in the clear. (These have been replaced with newer roof
trusses.)
In the years that followed, Severson worked as an architect and civil engineer, but none of his
architectural work and little of his engineering work has come to light. The Baltimore city directories
for 1858-60 list him as architect and engineer. By 1864, he had returned to Washington, D.C., where
he remained for the next twenty years. Here, too, the city directories list him as an architect or civil
engineer and sometimes as both. In the District, he served as Engineer of the Washington Canal and
was well enough known to be consulted by a Congressional committee about how to solve the chronic
problem of drainage and sewerage in this low-lying
His name disappears from Washington
directory in 1883, at which point he would have been about 74 years old. But his date of death is
unknown.
Despite his arguments in favour of compound girders, wrought iron came to be used increasingly
for larger spanning members in the 1860s, usually in the shape of '7"s (plate girders) and hollow
rectangles (box girders). Eventually, mills could roll solid I-section beams sufficiently deep so that
they could be used instead of fabricated wrought iron girders for many purposes. Even for holding
up walls in stores, constructors advised against using cast iron. For example, Robert Hatfield wrote
in his popular builders' handbook, The American House Carpenter, that a simple brick arch tied at
the ends could reliably sostain the sort of load usually carried by a bowstring girder. For this and
other reasons, he explained, 'The bowstring girder ... should never be used."24
Nevertheless, his weU-arranged truss, and his willingness to employ a novel material like wire
cable, make Severson one of the notable structural engineers of his day. His bridges do not seem to
have survived, and what work he did in buildings, apart from that at the Peabody Institute and
Philadelphia bank, is gone or, if surviving, hidden under ceilings. Such is the fate of the work of
structural engineers who design for buildings: their work is invisible to the public and, when successful,
taken for granted. At least a little light can now shine on one of these men.
(An earlier version of this article appeared in I.M.L. Ridge, ed., Rope Terminationsand Fittings,
Department of Engineering, University of Reading, 2001.)
Correspondence: Dr. Sara E. Wermiel, 70A South Street, Jamaica Plain, MA 02130 USA
E-mail: fireproof;?@worldnet.att.net
References
1. The findings of the Royal Commission on the Application of Iron to Railway Structures, and the
collapse of the Dee Bridge which prompted the creation of this body, were reported in Appleton's
Mechanics'Magazine and Engineers'Joumal 1 (185 1): pp.57-62,117-9. This article mentioned
two failed American bridges (both Ryder trusses): one on the New York and Erie Railroad road
near Lackawaxen, Pennsylvaniain 1850, the other near Buffalo. The formerprolllpted the railroad
company to remove all their iron bridges. (Llewellyn Edwards,A Record of History and Evolution
of Early American Bridges (Orono, Maine: University Press, 1959), pp.71-2)). Information on
the 1844 collapse of a fireproof mill in Oldham, England was available in the U.S., e.g., "The
Falling of a Mill at Oldham," Journal of the Franklin Institute 9 3d series, no. 5 (May 1845):
pp.289-98, reprinted from the London Civil EngineerandArchitect's Joumal 7 (1844). William
Fairbairn reprinted reports on this accident and the collapse of a section of a Manchester cotton
mill in his widely read book, On the Application of Cast and Wrought Iron to Building Purposes
(New York, 1854).
A n Unusual Application of Wire Cables from the 1850s:
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
Here, briefly, is the story of the discovery of Benjamin Severson and his surviving girders: I was
looking at original drawings of the Peabody Institute in Baltimore, Maryland (designed in 1857).
On one of the drawings, of an iron girder, was the note, "This is like that which I made for the
extensive Building of Fassits, in Philadelphia, in 1854," signed B. Severson. Not knowing who
this person was, I got in touch with Charles Peterson, who knows a great deal about Philadelphia
buildings, to ask if he had ever heard of Severson or "Fassits." He said no, but in his
characteristically generous way, he sent me two articles about structural iron, one of which was
Donald Sayenga's article about the F&M bank girders, "An Analysis of the Remarkable G-G-G
Iron Wire Cables," Association for Preservation Technology Bulletin (1994): pp.26-31. I had
not told Mr. Peterson what the Baltimore girders looked like; he had no idea he was providing
the information I sought. When I unsuspectingly turned to Mr. Sayenga's article and saw the
spitting image of Severson's Peabody girder, my hair stood on end. I soon made contact with
Mr. Sayenga and the engineers of the bank renovation, Keast & Hood Company.
Donald Sayenga, "Discovery and analysis of the remarkable G-G-G iron wire cables," 1995
Conference Proceedings of The Wire Association International, Inc: pp.302-5.
R. J. M. Sutherland, 'The Introductionof StructuralWrought Iron," Transactionsof the Netvcomen
Society 36 (1963-64): pp.73-4; William Fairbairn, On the Application of Cast and Wrought Iron
to Building Purposes, pp.52-3.
"Notices & Correspondence,"Appleton's Mechanics'Magazine crnd Engineers'Jo~rmal1 (185 1):
p.703, described the "usual practice, in this neighborhood" was to use a bowstring girder, 25-30
feet long, cast in one piece with a wrought iron tie rod connecting the lower ends. By 1850,
foundries in Philadelphia and New York City made such girders, for example, the New York
Wire Railing Co. in New York and H. C. Oram & Co. in Philadelphia. Around 1856, Oram &
Co. made 36 bowstring girders from 15 to 43 feet long. (EdwinT. Freedley, Philcrdelphia and its
Manufactzrres (Philadelphia, 1859), p.293.)
We know this from an article about another Severson invention (a cast iron sidewalk deck); see
Fairman Rogers, "Notice of a new Cast Iron Foot Pavement," Jo~rmalof the Franklin Institute
59 (1855): pp.88-9.
"Benjamin Severson's Iron Bridge," Scientific Anierican 6 (May 3,1851): p.260 and 'Great air
of the American Institute No. 1," Scientific American 5 (Oct. 13, 1849): p.29. This journal is
available online for the years 1846-1869 at Cornell University Library's contribution to the
Making of America collection, which can be found at http://cdl.library.cornell.edu/moa/. To see
issues of Scientific American cited in this article, click on browse, select Scientific American,
then select the yearlissue you want. The Clute Brothers foundry and machine shop manufactured
the turret engines, gun carnages, and other parts for the famous Civil War ironclad ship, the
"Monitor." (William Still, Jr., Monitor Builders (Washington,D.C.: National Maritime Initiative,
National Park Service, 1988).)
"Severson's Iron Bridge," Appleton 's Mechanics'Mcrgazine 2 (1852): pp.236-38. Severson held
one patent from the 1850s, for a cast iron car wheel (No. 11, 233; 1854).
B. Severson, "Results obtained from Testing the Strength of an Iron Girder, recently constructed
at the Architectural Iron Works of J. A. Gendell & Co., Philadelphia," Journal of the Franklin
Institute 57 (April 1854): pp.273-4. Severson used wrought iron bars in addition to wire cables
for ties, for ex'unple, in his iron roof trusses and an unexecuted design for a girder with wrought
iron ties measuring 2'12 inches across, both for the Peabody Institute. (Archives of the Peabody
Institute, architectural drawings, "Sections showing two modes of connecting the timber flooring
with the Iron Girders.")
This was the "Fassit" of Severson's note on the Peabody Institute drawing.
Elizabeth Schaaf, Guide to the Archives of the Peabody Institzlte of the Cily of Baltinzore 18571977(Baltinlore: Archives of the Peabody Institute, 1987). p.13. Archives of the Peabody Institute,
Sara E . Wermiel
architectural drawings, "Peabody Institute, Details of Iron Roof Girder & c ... as executed," and
observations of John McNair, retired structural engineer and an Archives volunteer.
12. From Charles Ellet, Jr., A Popular Notice of Suspension Bridges with a Brief Description of the
Wire Bridge across the Schuylkill, excerpted in Donald Sayenga, "A History of Wrought-Iron
Wire Suspension Bridge Cables," Proceedings of the International Conference on Historic
Bridges.. . Oct. 21 -23, 1999 (Morgantown, W. V. 1999). p.66 and "Wheeling Suspension Bridge,"
Scientific~merican-5(Nov. 3, 1849): p.53.
13. New York Wire Railing Co., A New Phase in Iron Manufacture (New York, 1857). Scientific
American in 1849-50 assumed less strength for No. 10 wire; it used the figure of 500 pounds to
break a strand. Thissort of calculation must be rough since several wire gauges were used in the
nineteenth century, and we do not know the precise as-built dimensions of Severson's cables and
thus the size of the individual wires.
14. "Test of Wrought Iron Girders," Scientific American 2 ns (Feb. 18, 1860): p.117. The Trustees'
architects required the test as a condition for making final payment to the foundry. It is not clear
from surviving records what sort of load the girder was supposed to support. Rather, the building's
architects just piled "a lot" of weight on the girder. Severson objected to the first test, but the
second one apparently satisfied all parties and the Trustees settled the bill. (Archives of the
Peabody Institute, Board of Trustees, Building Committee, Minutes - Committee Meeting, Box
I1 Dl1 12, folder 8.)
15. Benjamin Severson, "Iron Girders-No. 1," Scientific American 14 (Oct. 30, 1858): p.62.
16. One contemporary wire rope-tied truss was patented by John Bevan of New York City (Patent
No. 7,374; 1850). His invention consisted of a laminated wood arch with a wire rope encircling
the arch; the ends of the rope were clamped together in the center under the arch to form the
bottom tie. ("Bevan's Patent Arch Girder," Scientific American 5 (June 29, 1850): p.324.)
17. Daniel Badger, Badger's Illustrated Catalogue of Cast-Iron Architect~tre(New York: Dover
Publications, Inc., 1981, reprint of 1865 edition); Pennsylvania, vol. 133, p.94, R. G. Dun & Co.
Collection, Baker Library, Harvard Business School.
18. Results of a modem test of the Farmers and Mechanics Bank girder cable showed that the girder
was stronger with the wire cable than it would have been with an iron bar tie rod of the same size.
Put another way, a larger iron bar would have been required to achieve the same strength as the
cable. See Donald Sayenga, "Discovery and analysis.. .," p.305. By the 1840s, French engineers
had established that cables were stronger than iron chains for suspension bridges; see
"Observations upon the Comparative Advantages ... of the Employment of Iron Wire.. ." Journal
of the Franklin Institute 5 (1843): pp.95-101. The weight of the ties of the Fassitt's store girders
can be computed - 9 poundslfoot - but it is not known whether these were iron bars or wire
cables.
19. U.S. Census of Population, 1850, manuscript census. Other records suggest that Severson was
born January 26,1809, to parents who lived in Guilderland, New York, nearAlbany (from William
A. Brinkman, "Bible and Family Records," Guilderland, New York, 1943). The 1850 census
records indicate that Severson's wife came from Pennsylvania, so the family presumably had
connections in the Philadelphia area. (Thanks to Virginia LaGoy, Archivistflibrarian,Scbenectady
County Historical Society, for locating this genealogical material.)
20. Transcript of M. C. Meigs journal, entries for Aogust 8 and 9, 1856, Historical Office, U.S.
Senate.
21. Stephen Colwell letters to M. C. Meigs, September 6, 1855, Architect of the Capitol's Office,
RG 43, CapitoI Extension, 1851-1874, Personnel: Applications for employment, 1851-1874,
Box 17 and Aogust 12, 1856 (source of quote), Architect of the Capitol's Office, RG 43, Capitol
Extension, 1851-1874, Personnel: Employees on payroll, 1851-1874, Box 17.
22. Benjamin Severson, "Iron Girders," Scientific American 14 (Oct. 30, Nov. 6, Nov. 13, and Nov.
An Unusual Application of Wire Cables from the 1850s:
20,1858): pp.62.70.78, and 86; B. Severson, "Iron Combination Beams for Building," Scientwc
American 2 ns (April 7 and 14, 1860): pp.230 and 243. Regarding the history of rolled iron
beams in the U.S., see Sara Wermiel, "Army Engineers' Contribution to the Development of
Iron Construction in the Nineteenth Century," Public Works Historical Society, publication
forthcoming.
23. His reports include Memorial of Benjamin Severson, in relation to the Washington City Canal
(Washington: G.P.O., 1868), printed in Senate Misc. Doc. No. 103, 40:2 (1868); "Washington
Canal," House Misc. Doc. No. 36,40:3 (1868-69); and Planfor the improvement of the sewerage
and the sanitary condition of the District of Columbia (Washington: G.P.O., 1878), printed in
Senate Misc. Doc. No. 25, 45:3 (1878-79) Severson may have designed structural iron for the
New Orleans Marine Hospital in 1856 (building demolished).
24. R. G. Hatfield, The American House Carpenter 8th edition (New York, 1880), p. 163.