The Hares Hill Road Bridge is a single-span,

wrought iron Wrought iron is an iron alloy with a very low carbon content (less than 0.05%) in contrast to that of cast iron (2.1% to 4.5%), or 0.25 for low carbon "mild" steel. Wrought iron is manufactured by heating and melting high carbon cast iron in an ...

, bowstring-shaped

lattice girder A lattice girder is a truss girder where the load is carried by a web of latticed metal. Overview The lattice girder was used prior to the development of larger rolled steel plates. It has been supplanted in modern construction with welded ...

bridge A bridge is a structure built to Span (engineering), span a physical obstacle (such as a body of water, valley, road, or railway) without blocking the path underneath. It is constructed for the purpose of providing passage over the obstacle, whi ...

. It was built in 1869 by Moseley Iron Bridge and Roof Company and is the only known surviving example of this kind. The bridge spans French Creek, a Pennsylvania Scenic River.

Description

The Hares Hill Road Bridge

superstructure A superstructure is an upward extension of an existing structure above a baseline. This term is applied to various kinds of physical structures such as buildings, bridges, or ships. Aboard ships and large boats On water craft, the superstruct ...

consists of one wrought-iron lattice girder span. The ends are supported on stone masonry

abutments An abutment is the Bridge#Structure types, substructure at the ends of a bridge Span (architecture), span or dam supporting its Bridge#Structure types, superstructure. Single-span bridges have abutments at each end that provide vertical and l ...

built by Abraham Taney Jr., also in 1869. The bridge has been extensively rehabilitated several times, one of which added the current open grid steel deck. This is a single-lane bridge. The structure is listed in the

National Register of Historic Places The National Register of Historic Places (NRHP) is the Federal government of the United States, United States federal government's official United States National Register of Historic Places listings, list of sites, buildings, structures, Hist ...

and has a high degree of historical and technological significance: it is the only known surviving example of Thomas William Moseley’s patented "Wrought Iron Lattice Girder Bridge." The bridge has been recorded by the

Historic American Engineering Record Heritage Documentation Programs (HDP) is a division of the U.S. National Park Service (NPS). It administers three programs established to document historic places in the United States: Historic American Buildings Survey (HABS), Historic American E ...

(HAER) with detailed drawings, photographs, and a historical narrative. The structure carries one lane of traffic on Hares Hill Road (unsigned State Route 1045) across French Creek. Residences are located along the north bank of French Creek and a wooded area runs along the south bank. The abutments are founded on rock and consist of random rubble mortared sandstone. They are long, wide at the base, have a batter of 1/2 inch per foot (1:24), and are about high above low water. Concrete pedestals have replaced the original stone-bearing seats.

Wing walls A wing wall (also "wingwall" or "wing-wall") is a smaller wall attached or next to a larger wall or structure. Bridges In a bridge, the wing walls are adjacent to the abutments and act as retaining walls. They are generally constructed of the same ...

extend approximately with a slight flare on the south side. The north wings are about long. Hares Hill new deck

The original superstructure consisted of the two wrought-iron arched girders with lattice webbing and a timber floor system. The arch girders are made up of a pair of Z-shaped bars riveted to a central plate diaphragm. Diagonal lattice members fill the web between the upper and lower portions of the plate. Each arch has seven vertical members that support the floor system, along with the lattice and bottom tie plate. Bowstring-type tie rods extend diagonally from the bottom of the center vertical on both sides of each arch. The HAER narrative cites three major rehabilitation campaigns before 1991. Known locally as the "Silver Bridge" due to its color, the bridge was yellow for at least a few decades. The bridge was returned to silver during rehabilitation in 2010. View from southern side

In 2009, the

Pennsylvania Department of Transportation The Pennsylvania Department of Transportation (PennDOT) oversees transportation issues in the Pennsylvania, Commonwealth of Pennsylvania. The administrator of PennDOT is the Pennsylvania Secretary of Transportation, Michael B. Carroll. PennDOT ...

(PennDOT) was programmed to spend $1.7 million to rehabilitate this bridge and improve its load capacity without interfering with its historical nature. On June 22, 2010, the bridge was closed for rehabilitation work including replacement of the open-grid steel deck with a new deck incorporating a concrete center section for bicycle use. The $826,689 restoration was expected to last until October 2010 and raise the load restriction to 15 tons ( metric tons). The bridge was reopened on December 10, 2010. On June 11, 2018, the bridge closed for approximately ten weeks for the latest rehabilitation. PennDOT's contractor worked to rehabilitate the wrought iron through truss bridge by reconstructing damaged and deteriorated wingwalls; reconstructing stone masonry parapets with reinforced concrete; and installing powder-coated brown guiderail to protect the blunt ends of the parapets. In addition, the conserved historic plaque on the outside of the southeast wingwall was re-installed. A plaque commemorating this 2018 rehabilitation was also installed. The bridge reopened August 20, 2018.

References

External links

Crossroads of Kimberton
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History of Kimberton InnNBI Rating
{dead link, date=October 2017 , bot=InternetArchiveBot , fix-attempted=yes Bridges completed in 1869 Bridges in Chester County, Pennsylvania Road bridges on the National Register of Historic Places in Pennsylvania Historic American Engineering Record in Pennsylvania Tied arch bridges in the United States Wrought iron bridges in the United States 1869 establishments in Pennsylvania National Register of Historic Places in Chester County, Pennsylvania Lattice truss bridges in the United States

Description

See also

References

External links