Driving along East Harford Street in Milford, a compact borough in Pike County nestled between National Historic Landmark Grey Towers and National Park Service’s Delaware River National Recreational Area, it is easy to miss Mott Street.

A late 19th century home now hosting the regional newspaper is on one corner of Mott and East Harford and a low, one-story carpet shop is on the other.  It looks a lot like the other small alleys branching off the borough’s main drag. The narrow street lined with a handful of well-maintained residences shields the newly rehabilitated steel truss bridge at the road’s end.  

Mott Street Bridge’s Story

The Penn Bridge Company constructed the Mott Street Bridge in 1902-1903 to carry traffic over Sawkill Creek.

Advertisement for The Penn Bridge Company.
The Penn Bridge Company fabricated metal truss road and railway bridges out of New Brighton and later Beaver Falls, Pennsylvania, from 1868 through the 1930s. Source: Penn Bridge Company (Beaver Falls, Pa.). Iron Highway Bridges: As Built by the Penn Bridge Company. Beaver Falls, Pa.: The Co., 1886, page 2. Accessed online, 5/17/2021, https://catalog.hathitrust.org/Record/102484120/Home.
1907 postcard of Mott Street Bridge, downstream looking north. Note the falls and other structures harnessing the power of Sawkill Creek for use by the nearby mills and factories. Source: PennDOT project files.
1910 postcard of Mott Street bridge, view from the west, on current National Park Service land, looking east on Mott Street toward the intersection with E. Harford Street. The two signs hanging from the entry portal and strut were not present when the rehabilitation started. Source; PennDOT project files.

The structure is located between two dams that powered the many small industries along the waterway.

1872 map of Milford, created thirty years prior to the Mott Street Bridge’s construction. The dark blue star shows the location of the bridge. Note the many industries along Sawkill Creek, including a spoke factory, grist mill, planing mill and fanning mill (where grains are separated from stones and contaminants). Source: Beers, Frederick W. Topographical map of Pike County, Pennsylvania: from recent and actual surveys and records. New York: F.W. Beers & Co., 1872. Accessed online, 5/17/2021, https://www.loc.gov/resource/g3823p.la000786/.

Until 1988, it continued to carry vehicular traffic between downtown Milford to the north and a local road and the National Park Service’s northern trail system to the south. From 1988 to 2006, the crossing was restricted to pedestrians only. By 2006, deterioration closed the bridge to all modes of traffic.

Mott Street Bridge closed to traffic. Source: Kevin Mock, PennDOT, December 2014.

Example of a Pratt Thru Truss

Mott Street Bridge is a Pratt thru truss.  The Pratt truss was first introduced in the mid-nineteenth century and became the most common metal truss bridge in use in the early twentieth-century.  

In 2019, the Pennsylvania State Historic Preservation Office (SHPO) and Pennsylvania Department of Transportation (PennDOT) reevaluated the National Register eligibility of the Commonwealth’s metal truss bridge population.  Today, Pratt trusses make up the majority of the surviving metal truss bridge population.  

A Pratt truss gets its strength from diagonal members in tension and vertical members in compression.

Mott Street Bridge in the beginning of rehabilitation. Some members mentioned in the blog are numbered: 1) truss, which includes the whole polygon on each of the bridge’s long sides that extend over the creek; 2) top lateral bracing; 3) strut featuring decorative latticework; 4) vertical featuring decorative latticework; 5) portal strut; 6) diagonal. Source: Kris Thompson, PennDOT.

The two sides (trusses) of a thru bridge are connected at the top and bottom by lateral bracing and struts. Some of Mott Street’s structural components are joined by pins and rivets.  U-bolt hangers bring the trusses and floorbeams together.

Mott Street Bridge, downstream side, merging of diagonals, verticals, floorbeams, tie rods, and U-bolt hangers. Source: Kris Thompson, PennDOT.

Metal strips form latticework on the verticals, portal strut, top lateral struts, and the decorative railing. The truss sits upon tall stone abutments. Penn Bridge Company memorialized their effort with a bridge marker on both portals.

The decorative bridge marker on top of the portal strut, prior to rehabilitation (left) and after rehabilitation (right). The marker dates the bridge, prominently notes the Penn Bridge Company as builders, and lists the county commissioners and clerk. The image to the left was taken prior to the rehabilitation; the image to the right is post-rehabilitation. Source: Kris Thompson, PennDOT.

Preserving Mott Street Bridge

Pike County, owners of Mott Street Bridge, understood the importance of maintaining a link between the borough and the National Park Service’s trails. A bridge replacement was initially proposed to address this need. Due to the willingness of  county commissioners to maintain the historic structure, rehabilitation and continued use by pedestrian traffic resulted in a preservation outcome.

The Pennsylvania Department of Transportation (PennDOT) awarded the county a Transportation Alternatives Program (TAP) grant to help maintain the crossing’s connectivity. The TAP grants are federally funded [through the Federal Highway Administration (FHWA)], which requires PennDOT to consider effects of the project on National Register-eligible and -listed properties.

The Mott Street Bridge (PA-SHARE Resource #2004RE10587) was determined eligible for the National Register of Historic Places for its technological significance. It also contributes to the National Register of Historic Places-listed Milford Historic District (Boundary Increase, PA-SHARE Resource #1998RE00132).

PennDOT, on behalf of FHWA, coordinated the project scope with the county, the Pennsylvania State Historic Preservation Office, the National Park Service, and members of the public (called Section 106 Consulting Parties) to ensure the work complemented the bridge’s original design, materials, and engineering. Repairs were made with similar materials and design features. Components too deteriorated to be repaired were replaced.  Where possible, the replacement parts match the historic materials and design.

Mott Street Bridge after rehabilitation was complete, taken from the Milford side looking toward the National Park Service land to the southwest. Source: Kris Thompson, PennDOT.
Mott Street Bridge, post-rehabilitation, looking northeast from southwest of the structure, showing the floorbeams and stringers, connections, restored bridge plaque, and the new pedestrian railing. Source: Kris Thompson, PennDOT.

The result is a rehabilitated pedestrian bridge that connects scenic trails and Milford’s walkable historic downtown.

Representatives from Pike County, National Park Service, and PennDOT District 4-0 at re-opening ceremony, January 2020. Source: Kris Thompson, PennDOT.

This week’s guest author is Kristina Lammi Thompson. Kris is a Cultural Resources Specialist for PennDOT’s District 5 and an Above-Ground Cultural Resources Supervisor with PennDOT’s Bureau of Project Delivery.