government under the direction of county engineer Alban P.Shaw and general contractor Charles H. Dunleavy of Coatesville,Pennsylvania, the bridge is handsomely detailed with the fasciascored to appear like stone voussoirs. The uncommon cantileverdesign allowed for ease of construction with a minimum of false-work. It is similar to the earlier 1928 North Market Street Bridgeover Brandywine Creek (State Bridge NC-575) in Wilmington, al-so a cantilevered multi girder bridge.

In 1993, deteriorated concrete encase-ment, deck, sidewalks, and parapets wereremoved by DelDOT and replaced using alightweight concrete. Original architecturaldetails, such as battered pylons and balust-rades were carefully reproduced. Althoughnew from the deck up, the bridge’s unusualcantilevered steel multi girder superstruc-ture remains intact, and the rehabilitationwas done in a sensitive manner that doesnot detract from the original design.

The bridge is located in the RocklandHistoric District, a 19th-century mill village withformer paper mill, converted to condominiums.

135

Metal Girder Bridges

ABOVE: The 1932 Rockland Roadover Brandywine Creek bridge(State Bridge NC-2) is an unusualcantilevered steel multi girderdesign with Moderne-style details.The railings and pylons were repro-duced carefully following a 1993rehabilitation project by DelDOT.

LEFT: The underneath view of theRockland Road bridge shows thehaunched, encased steel girders.

The mill race and dam are upstream ofthe bridge. The steel multi girder bridge from1933 replaced a wooden covered trussbridge that had carried Rockland Roadsince 1833.

Washington Street overMispillion River

State Bridge K-501Milford, Kent CountyDesigner/Builder: Unknown

1933

The 1933 Washington Street bridge is askewed, one-span, 44’-long, 41’-wide

steel multi girder bridge. It has concrete di-aphragms. It is finished with incised pan-eled concrete parapets and supported onconcrete abutments. Two concrete lightstandards remain on the east side of thebridge but have been lost from the westside. State records indicate the bridge wasbuilt by Milford City in 1933. The designer

136W

ashington Street

Milford

Washington Street BridgeK-501

➲

N

Rehoboth Rd.

2nd Street

36

14

Mispillion River

South Front Street

North Front Street

213

The 1933 Washington Street bridge in Milford (State Bridge K-501).

and contractor are not listed in staterecords. The bridge is a well preserved ex-ample of the standard steel multi girderbridge type built by state, county and mu-nicipal governments throughout Delawareand the United States, from the 1910sthrough the 1930s.

Silver Lake Road (Road 442)over Silver Lake Spillway

State Bridge NC-407Southeast of Middletown,New Castle CountyDesigner/Builder: Unknown

1935

The Silver Lake Road bridge is a one-span, 22’-long, 22’-wide, encased steel

multi girder bridge. It is supported on con-crete abutments with wingwalls directingthe flow of water on the downstream sideof the Silver Lake dam spillway. The spill-way floor is an invert concrete slab. The

bridge is finished with concrete parapetswith diamond-shape panels and endpostpylons on the west elevation only. The py-lons support concrete flower planters. A steelgate frame with wood sluice gates is builtinto the bridge’s upstream side for control-ling water flow from Silver Lake. The lakeis a former mill pond, associated with agrist mill located at the northeast corner ofthe earthen dam. The mill has been con-verted to apartments.

The bridge is a representative exampleof the steel multi girder bridge type thatwas prevalent in Delaware during the firsthalf of the 20th century. It was chosen for

its historical and technological significancefrom the population of similar multi girderbridges because of its historic associationwith the dam/spillway, custom-design para-pets, and integrity of original design.Records state that the superstructure of thebridge was placed in 1935 after a flood hadpartially destroyed the previous bridge.

137

Metal Girder Bridges

Middletown

➲

N

Silver Lake

71

301

299

Road

RiverAppoquinimink

SilverLake

NoxontownLake

Noxontown Lake Rd.

Silver Lake Road BridgeNC-407

St.Ann

esCh

urch Rd.

The 1935 Silver Lake Road bridge(State Bridge NC-407) spans theSilver Lake Spillway. Sluice gates arebuilt into the bridge’s upstream side.

The bridge was rebuilt reusing the surviv-ing abutments, which were placed in 1931.An inscription in the north abutment con-firms the 1931 date. The bridge was builtby the county, but no engineer or contrac-tor are cited in any available records.

Carr Road (Road 213)over Shellpot Creek

State Bridge NC-543Bellevue State Park, New Castle CountyDesigner/Builder: Delaware StateHighway Department/Union PavingCompany

1936

The Carr Road bridge, built in 1936 bythe state highway department, is a one-

span, 40’-long, 37’-wide, steel multi girderbridge consisting of nine lines of rolled I-beams. The fascia beams are haunched andhave a stone veneer to present the appear-ance of an arch bridge. The bridge is sup-ported on stone abutments with U-shapedwingwalls and is finished with stone para-pets and a corbeled stone belt course ex-tending across the fascia at roadway level.Stone pilasters are located at each of theabutment corners. The pilasters form theparapet end posts, which are decorated

138

➲

N

Shellput Creek

Ship

ley

Road

13

Mar

sh R

oad

Rockwood Road

Silver Lake Road BridgeNC-407

3

Exit9

RockwoodMuseum

CarrRoad

Washington St. Ext.

BellevueState Park

95

The 1936 Carr Road bridge (State Bridge NC-543) has stonefacing and parapets to present a rustic appearance.

with diamond-shape outsets. The Carr Road bridge is historically sig-

nificant as a complete example of a 1930ssteel multi girder bridge with stone facingand parapets to give a rustic appearance. Itwas built as part of a project to construct anew spur road off of Washington StreetExtension to Carrcroft, a distance of 1.42 miles,passing through a forested section of theBellevue Estate, now a state park. The De-laware State Highway Department awardedthe contract for the road and bridge to theUnion Paving Company of Philadelphia forover $50,000.

Contract drawings and notes provide in-sight into the desire to construct the bridgewith a stone facing and parapets. State BridgeEngineer Arthur G. Livingston commentedthat “the site shows exposed rock thicklylocated around the entire vicinity; con-

139

Metal Girder Bridges

struction should conform as closely as pos-sible to the surrounding country.” He alsoindicated his design was influenced by othernearby stone-faced structures: “[The bridge]will be similar to the structure already built

across the same stream about a half a mile[away]. This will make on the ShellpotCreek three rubble masonry structures andan I-beam span on the Industrial Highway.”Livingston, like many bridge engineers, was

Elevation and section drawings for the Carr Road bridge. The drawings were pre-pared by the state highway department’s bridge division in 1933.

influenced by the ideas of landscape archi-tects who promoted the idea that a struc-ture’s surrounding should influence its form.Stone masonry was an appropriate responseto the landscape of upper New Castle County,where there are many rock outcroppingsand buildings, walls, and fences built of na-tive granite.

State Route 7over Christina RiverState Bridge NC-257Christiana, New Castle CountyDesigner/Builder: Delaware StateHighway Department

1937

The State Route 7 bridge is a one-span,66’-long, 39’-wide, steel multi girder

bridge built in 1937 by the Delaware StateHighway Department. The fascia girders havebeen faced with stone to appear as shallowstone arches complete with voussoirs andkeystones. The bridge is finished with stonebalustrades and parapets over the wing-

140

Plans for repairs to the State Route 7 bridge in 1996. DelDOT redecked the bridge, repointed themasonry, and strengthened the rolled I-beam girders with stiffener plates and diaphragms. Therepairs maintained the bridge’s historic appearance.

walls. It is supported on rubble masonryabutments. The bridge is historically signif-icant as one of the longest and best pre-served of several 1930s stone-veneered steelmulti girder bridges in New Castle County.State Bridge Engineer Arthur G. Livingstondesigned the bridge with local stone toblend with the natural environment andimitate traditional stone arch construction.

Original drawings on file at DelDOT in-dicate that the State Route 7 bridge re-placed a pony truss swing span bridge atthe same location. The center-bearing swingspan was supported on rubble masonry pierand abutments with wingwalls, and specifi-cations for the replacement structure al-lowed for the reuse of the stone, providingit was cleaned and free of all mortar. By the1930s, the upper reaches of the ChristinaRiver were no longer important to naviga-tion, and permission was received from theU. S. Army Corps of Engineers to replacethe movable bridge with a fixed span.

The bridge underwent repairs in 1996.

141

Metal Girder Bridges

State Route 7 BridgeNC- 257

Creek

Christiana

Old Baltimore Pike

ChristianaMall

➲

N

7

273

Main Street

Exit3

95

Chr

istia

na 1

The 1937 State Route 7 over Christina River bridge (State Bridge NC-257) is one of thelongest of several 1930s stone-veneered steel multi girder bridges in New Castle County.

It was redecked using a lightweight con-crete, the stone balustrades were repointed,and the rolled I-beam girders strengthenedwith stiffener plates welded to the webs.The sidewalks were divided from the road-way by the addition of metal pedestrian

barriers. The repairs were performed in amanner sensitive to the original materialsand that maintained the bridge’s originalappearance from both elevations.

The bridge straddles the southeasternboundary of the Christiana Historic District,a commercial village that thrived prior to

1850 because of its location at the ChristinaRiver’s navigable headwaters.

Snuff Mill Road (Road 244)over Red Clay Creek Tributary

State Bridge NC-88West of Centreville, New Castle CountyDesigner/Builder: Delaware StateHighway Department/Olivere Paving &Construction Company

1939

The Snuff Mill Road bridge is a one-span,37’-long, 27’-wide, encased steel multi

girder bridge supported on concrete abut-ments. The bridge has stone faced veneerand stone parapets. Built in 1939, thebridge is a complete and well-proportionedexample from among several similar stone-faced multi girder bridges built in NewCastle County during the 1930s. Thisbridge was designed by the Delaware StateHighway Department’s bridge departmentand built by contractor Olivere Paving &

142

The 1939 Snuff Mill Road bridge (State Bridge NC-88).

➲

N

Snuff Mill Road BridgeNC- 88

Trib

utar

y

Centreville

Kennett Pike

Snuff Mill Road

Cent

erm

ill Ro

ad

Ashl

and

to C

linto

n Sc

hool

Roa

d

Way or Graves

Road

Old Kennett Pike

Red

Cla

yC

reek

WinterthurMuseum

Pennsylvania

Delaware

52

Construction Company of Wilmington.The department instructed the contractorto match the stone for the bridge with stoneused by Mr. Haskell, owner of an adjacentestate property. The bridge is another ex-ample of the department’s efforts to matchits bridges with the existing landscape.Nationally, stone veneers were applied fre-quently to steel girder and other bridgetypes like reinforced concrete arches andslabs beginning in the early 20th century.In northern New Castle County, the prac-tice reached its height during the 1930s.

State Route 82 (Mt. Cuba Road)over Red Clay Creek

State Bridge NC-119Ashland, New Castle CountyDesigner/Builder: Delaware State HighwayDepartment/Olivere Paving & ConstructionCompany

1939

Built in 1939 by the state highway de-partment, the State Route 82 bridge is

143

Metal Girder Bridges

➲

NState Route 82 Bridge

NC-119

Shar

pless Road

illeRoad Barl

Ashl

and

toCl

inton

ville

Scho

olRo

ad

Ashland

82Wilmington

&W

esternRailroad

RedCl

ayC

reek

The 1939 State Route 82 bridge(State Bridge NC-119) over Red ClayCreek has distinctive Moderne-stylestepped pylons at the corners. Itillustrates the adoption of then-current architectural styles toembellish common bridge types, suchas the steel thru girder bridge type.

a one-span, 110’-long, 27’-wide, steel thrugirder bridge with distinctive Moderne-stylestepped pylons at the corners. The concretewingwalls are finished with concrete para-pets with stepped end posts. The super-structure consists of two, 7’-deep, built-upgirders with I-beam floorbeams carrying aconcrete slab deck. The bridge is supportedon concrete abutments.

The thru girder bridge is an example ofa common 20th-century bridge type withfine custom details, illustrating the adop-tion of Moderne-style parapets by the statehighway department in the late 1930s.Moderne style railings continued to be usedby the department through the 1950s.Thru girder bridges were most often builtas utilitarian structures devoid of embell-ishment, and this bridge illustrates the ex-tra efforts that Delaware’s state highway de-partment often took with custom details.

The previous bridge at this crossing wasa covered bridge that was destroyed by a

144

The photo shows the bridge as it appeared when completed in August 1939. The adjacent trussrailroad bridge, which carries a single track of the Wilmington & Western Railroad, still exists.

flood on July 13, 1938. The state highwaydepartment bridge department designedthe replacement bridge and awarded thecontract to Olivere Paving & ConstructionCompany of Wilmington for approximately$28,500 in December 1938. A portion ofthe replacement cost was funded by thefederal New Deal program administered bythe Public Works Administration.

State Route 20 Eastbound (SteinHighway/ Tull Crossing) over Conrail(Delaware Railroad) and Cedar Street

State Bridge S-257ESeaford, Sussex CountyDesigner/Builder: Delaware StateHighway Department/M. J. McDermott

1940-41

The 21-span, 567’-long bridge consistsof a 40’-long encased steel multi girder

main span over the railroad, and continuous,variable-depth, reinforced concrete slab ap-

145

Metal Girder Bridges

Blades

State Route 20S-257E

High St.

➲

N

Seaford

Nanticoke River

Fron

t St

.M

arke

t St.

13

20

20

13

Concord Rd.

proach spans. The bridgeis finished with handsomeconcrete parapets withbush hammer-finish pan-els and red diamond-shaped tiles. It is support-ed on arched concretebents with brackets. Thebridge has no history ofsignificant alterations ormodifications, although ithas been converted from two-way to one-way traffic.

Built in 1940-41 for the state highwaydepartment, the State Route 20 bridge ishistorically significant as a complete exam-ple of a New Deal-era grade crossing elimi-nation bridge with Moderne-style details.The bridge, also known as “Tull Crossing,”was designed to eliminate a grade crossingwith the Delaware Railroad, a division ofthe Pennsylvania Railroad, on the northeastend of Seaford. In the early 20th century,

grade crossings posed an increasingly dan-gerous junction between railroad and high-way traffic, accounting for thousands of fa-talities in the United States. Railroads tookmeasures to eliminate dangerous crossings,especially in congested urban areas whereautomobile traffic also caused delays to therailroad’s own traffic, but it was not until af-ter 1919 and the era of federal and statefunding for highways and bridges that

wholesale grade crossing elimination pro-grams were undertaken outside of largercities. The Delaware State Highway Depart-ment announced a systematic program toeliminate hazardous crossings in 1926, andthis effort was supplemented after 1935 bya New Deal program that offered federalfunding for such overpasses. In 1940-41,the State Route 20 bridge was built withfederal funding from the Federal Aid GradeSeparation program matched by funds fromthe Delaware State Highway Department

and the Pennsylvania Railroad.The state highway department’s bridge

department designed the State Route 20bridge with the final plans forwarded to thePennsylvania Railroad’s engineering depart-ment for approval. The contractor for thebridge was M. J. McDermott of Georgetown,Delaware, for a price of over $74,000. Asfirst contemplated, the bridge was to haveapproach embankments on fill, but thiswas abandoned as aesthetically unsuitablefor an in-town location where an open-type

structure of approach spans on concretebents was preferred. It provided better ac-cess to properties adjacent to the structure.

The approach spans are an early use ofcontinuous, variable-depth, reinforced con-crete slab technology. The continuous designis an economical use of material, allowinglonger spans for the given depth of slabthan would have been possible with sim-ple, non-continuous spans. Continuous de-signs, both in reinforced concrete and steel,came to the fore nationally in the 1930s,

146

The 1940-41 State Route 20 bridge (State Bridge S-257E) is historically significant as a complete example of a New Deal-program grade-crossingelimination bridge with Moderne-style details.

and were ubiquitous by the late 1940s andearly 1950s.

State Route 141 (Tyler McConnellBridge) Over Brandywine CreekAnd Road 260 (Brecks Lane)

State Bridge NC-587East of Greenville, New Castle CountyDesigner/Builder: Parsons, Brinckerhoff,Hall & MacDonald/James Julian Inc.

1951-52

The 12-span, 816’-long Tyler McConnellBridge consists of three-span continu-

ous, haunched, built-up, deck girder mainspans with span lengths of 87’-156’-87’,flanked by six, 53’-long steel multi girderspans to the west, and three to the east. Themain spans have rolled steel floorbeams,stringers, and crossbracing. The concretedeck is finished with concrete safety shapeparapets with metal hand railings, placed in

1980-82. The 33’-wide bridge is supportedon reinforced concrete abutments and highreinforced concrete hammer head piersconsisting of hammer-shaped pier caps in-tegral with single column stems. The piers areaccented by checkerboard-pattern scoring.

The Tyler McConnell Bridge, built in1951-52, is a technologically significant deckgirder bridge reflecting important mid-20th-century refinements of the steel girderbridge type. The bridge is Delaware’s largestpre-1957 continuous steel girder bridge,and one of the earliest documented exam-ples of the use of hammer head piers in thenation. Long-span continuous steel girderbridges were increasingly popular after1945 because of the economy of materialachieved in comparison to simply support-ed spans. Continuous designs allowed forlonger spans for the given depth of beam.The 156’-long haunched girders reflect thiseconomy of material, achieving their great-

147

Metal Girder Bridges

Bran

dywine

River

Cancake Run

52

Bartley Mill Road

Risin

g Su

n La

neKennett Pike

Brecks Lane

HagleyMuseum

New

Brid

geRo

ad

DuPontExperimental

Station

RockfordPark

141

State Route 141 BridgeNC-587

Wilmington

➲

N

est depth over the piers of the main spanwhere the stresses are greatest.

Hammer head piers were an importantrefinement of substructure design. They werefirst used beginning in the early 1950s andbecame increasingly popular because of the

economy of material, lessening the weighton the foundation and cost of construction.The style of pier was made possible in partbecause of the increased availability of higherstrength concrete. The hammer head designhad the additional advantage of less foun-dation work in the ground. The design wasfrequently used for the interstate highwayprograms of the 1960s and 1970s, and itcontinues to be built. Thus, the 1951-52, TylerMcConnell Bridge documents the introduc-tion of an important new substructure design.

Planning for the bridge began in 1948,when the E. I. DuPont de Nemours Company(DuPont) approached the state highway de-partment with its plans to expand its ex-perimental station on the east bank of theBrandywine Creek in North Wilmington.The company desired better access to thefacility, and it offered to donate $250,000toward the construction of a new bridge(about half the original cost), as well as pro-vide preliminary survey work.

In cooperation with DuPont, the state

highway department hired Parsons, Brincker-hoff, Hall & MacDonald, consulting engi-neers of New York City, to design the bridge.Assigned to the project was the firm’s chiefbridge engineer, Alfred Hedefine (1906-1981), one of the nation’s leading bridgedesigners of the mid-20th century. He waslargely responsible for such importantstructures as the 1939 World’s Fair Trylonand Perisphere; the Talmadge Bridge,Savannah, Georgia (1950-51); the ArthurKill Bridge, Staten Island, New York (1959);the Newport Suspension Bridge, Newport,Rhode Island (1965-69); and, the FremontBridge, Portland, Oregon (1973).

The first task facing Hedefine was con-sideration of a steel arch bridge versus a steeldeck girder bridge for the Brandywine Creekcrossing. Although all agreed that the for-mer was more aesthetic, calculations provedthe latter design far more economical, andthe deck girder bridge was selected basedon cost. It was Hedefine who met withDelaware state officials at the bridge site in

April 1950, presenting a sketch of a new typeof pier with a hammer-head shape andrecommending its substitution for moreconventional bents or solid-stem piers.Construction began in February, and the piers,perhaps the most innovative part of theproject, were a detail of frequent discussionbetween the engineers and the contractor,James Julian of Wilmington. Having no ex-perience with the construction of hammerhead piers, careful consideration was givento the formwork, with several revisions madebefore Hedefine was satisfied that it wasstrong enough to support the cantileveredportion of the pier heads. Although thesubstructure was complete by late 1951, asteel strike delayed delivery of the super-structure from the Phoenix Bridge Company,Phoenixville, Pennsylvania, until June 1952.The bridge opened to traffic in December1952, and was dedicated the J. H. TylerMcConnell Bridge in April 1953. McConnellwas a member of the Delaware StateHighway Commission. ■

148

149

Metal Girder Bridges

The reinforced concrete hammer head piers were an innovative design, lessening theweight on the foundation and reducing the cost of construction. The Tyler McConnellBridge is one of the nation's earliest documented uses of hammer head piers. Theyremain one of the most popular pier types in use today.

ABOVE: Tyler McConnellBridge (State Bridge NC-587) over the BrandywineCreek as seen from down-stream. Opened inDecember 1952, thebridge provided a newcrossing of the streamnear the DuPont Company'sexperimental station.

RIGHT: The TylerMcConnell Bridge wasconstructed during 1951-1952. It is Delaware'slargest pre-1957 continu-ous deck girder bridge.