2 votes

Gerloff Road Bridge


Gerloff Road Bridge

August 2006-Phoenix Bridge Co. (Builder)

Photo taken by Raymond Klein


BH Photo #132342

Street View 


Pratt through truss bridge over Swamp Creek on Gerloff Road near Zieglersville, PA
Montgomery County, Pennsylvania
Open to traffic
Built 1888, closed to traffic in mid 1970's; Rebuilt by High Steel Structures & reopened July 1998
- Phoenix Bridge Co. of Phoenixville, Pennsylvania
Phoenix Pratt Truss. Arch added during reconstruction
Length of largest span: 133.9 ft.
Total length: 138.1 ft.
Deck width: 15.1 ft.
Vertical clearance above deck: 17.4 ft.
Posted to the National Register of Historic Places on June 22, 1988
Also called
Bridge in Upper Frederick Township
Approximate latitude, longitude
+40.27500, -75.48500   (decimal degrees)
40°16'30" N, 75°29'06" W   (degrees°minutes'seconds")
Approximate UTM coordinates
18/458767/4458393 (zone/easting/northing)
Quadrangle map:
Average daily traffic (as of 1999)
Inventory numbers
PA 46 7206 0030 2039 (Pennsylvania Bridge Management System number)
NRHP 88000838 (National Register of Historic Places reference number)
PANBI 27816 (Pennsylvania BRKEY bridge number on the 2011 NBI)
BH 31360 (Bridgehunter.com ID)
Inspection report (as of February 2017)
Overall condition: Good
Superstructure condition rating: Good (7 out of 9)
Substructure condition rating: Good (7 out of 9)
Deck condition rating: Good (7 out of 9)
Sufficiency rating: 76 (out of 100)
View more at BridgeReports.com

Update Log 

  • July 5, 2020: New photos from Patrick Gurwell
  • September 24, 2016: New Street View added by Dana and Kay Klein
  • March 6, 2014: Photo imported by Dave King
  • February 24, 2009: Updated by Raymond Klein: Added near Zieglersville to overview and City & added High Steel Structures in history re who rebult it
  • February 14, 2009: Updated design
  • February 14, 2009: Updated by Wayne Kizziar
  • February 14, 2009: New photo from Raymond Klein
  • January 13, 2009: Updated by Raymond Klein
  • January 12, 2009: New photo from Raymond Klein


  • Raymond Klein - Bookshelfthe [at] msn [dot] com
  • Wayne Kizziar - waynekizziar [at] gmail [dot] com
  • James Baughn - webmaster [at] bridgehunter [dot] com
  • Historicbridges.org - by Nathan Holth
  • Dana and Kay Klein
  • Patrick Gurwell - pgurwell [at] gmail [dot] com


Gerloff Road Bridge
Posted February 19, 2010, by Nathan Holth (form3 [at] historicbridges [dot] org)

Yes, deck stringers and deck surface are frequently not original, and their replacement is not considered to reduce the historic integrity of the bridge because it is considered part of routine maintainance and is often done many times over the life of a properly maintained bridge. Floorbeams are a different story. As a part of the actual superstructure, their replacement represents a loss of historic integrity. I would comment that on a percentage basis, most truss bridges retain original floorbeams. Usually the reason for them having original floorbeams is due to neglect rather than preservation. This is unfortunate, since I would like to see original floorbeams retained during preservation work, but often they are discarded and replaced with modern wide flange beams. At the very least, original floorbeams could be replaced with new replicas instead of modern substitutes.

Gerloff Road Bridge
Posted February 19, 2010, by Anonymous

Floor systems were replaced often. While the truss itself often remains intact, the deck and floorbeams and stringers are rarely original.

Gerloff Road Bridge
Posted February 10, 2010, by Nathan Holth (form3 [at] historicbridges [dot] org)

Yes, this form of retrofit shows up in many places. Have seen examples in Michigan, New York, Maryland, and New Jersey as well as Pennsylvania.

Placement of stringers underneath floorbeams is generally considered a less visually obtrusive method if a retrofit or structural bypass to render the trusses decorative is determined to be the only viable preservation solution.

Retrofit can sometimes be better than rehabilitation because it may be possible to add stringers or the arch and thus not have to remove or replace original bridge material to provide loading requirements. However in most cases I have seen these arches added, I have also found the entire flooring system replaced, representing loss of original bridge material, so in that respect I fail to see any benefit.

Gerloff Road Bridge
Posted February 10, 2010, by Anonymous (yo [at] yo [dot] com)

There are several of these across PA. The retrofitted arch was championed by now-retired Bucknell University engineering professor Dr. Jai Kim.

Gerloff Road Bridge
Posted February 7, 2010, by Anonymous

What a horrible mess! Id be ashamed to admit I had anything to do with this so called reconstruction.

Gerloff Road Bridge
Posted February 7, 2010, by Anthony Dillon (spansaver [at] hotmail [dot] com)

I have to hold my ground on this one......but I will soften my tone just a bit. I feel like it destroys the integrity of the bridge to weave a new structure into it. It is hard to enjoy the beauty of the original trusses when your attention is drawn to a massive arch. I was the inspector on an 1887 wrought iron bridge rehabilitation. The bridge was restored in-kind with minimal changes and now carries a 15 ton load limit. The right engineering firm would have approached the rehab differently, and with better results.

However, I guess the fact that PennDOT even kept a historic bridge should account for something.

Gerloff Road Bridge
Posted February 7, 2010, by Craig Philpott (cphilpott [at] puc [dot] edu)

Opposing view, I see this not as a hack job but rather an innovative method to not only preserve in place, but to re-open for use an historic bridge. Here is a link to the repair company. http://www.highsteel.com/project_gallery/bridges/GerloffRoad...

Gerloff Road Bridge
Posted February 27, 2009, by Anthony Dillon (spansaver [at] hotmail [dot] com)

This is about as bad of a HACK job on an otherwise unique structure that I have seen. What a waste on a span that could have been restored the right way.

Gerloff Road Bridge
Posted January 12, 2009, by Ian Anderson (macsignals [at] gmail [dot] com)

This appears to have been a through truss that PennDOT or the Twp. slapped some arches on to keep it standing. My bet is that truss is no longer holding anything but itself.

I've seen an example of this somewhere, just gotta find it...