HistoricBridges.org Menu: HistoricBridges.org Menu:


We Recommend These Resources:
Bach Steel - Experts at historic truss bridge restoration.
Historic Bridge Finder App: Find Nearby Bridges

HistoricBridges.org: Bridge Browser

Scioto Darby Road Bridge

Scioto Darby Road Bridge

Primary Photographer(s): Nathan Holth and Rick McOmber

Bridge Documented: March 2, 2007

View Photos
and Videos
View Maps
and Links

Key Facts

Facility Carried / Feature Intersected
Scioto Darby Road Over Big Darby Creek
Location
Rural: Pickaway County, Ohio: United States
Construction Date and Builder / Engineer
1910 By Builder/Contractor: Oregonia Bridge Company of Lebanon, Ohio

Technical Facts

Rehabilitation Date
1986
Main Span Length
125 Feet (38.1 Meters)
Structure Length
255 Feet (77.72 Meters)
Roadway Width
17.4 Feet (5.3 Meters)
Spans
2 Main Span(s)
NBI Number
6530192

Historic Significance Rating (HSR)

Bridge Documentation

This bridge no longer exists!

View Archived National Bridge Inventory Report - Has Additional Details and Evaluation

This attractive bridge is a rare example of a pin-connected truss bridge that remains in use for vehicular traffic in genuinely good condition, but also with excellent historic integrity. Each span is composed of eight panels. Original lattice railings remain on the bridge behind modern railings. Vertical members feature v-lacing, with lattice on the sway and portal bracing. The sway bracing is nearly identical to the portal bracing. The bridge may have not been considered historic by Ohio's Historic Bridge Inventory, but it is HistoricBridges.org's opinion that this bridge still has heritage value and a large amount of aesthetic quality as well. As such, the bridge is worthy of preservation. Many of the other better examples that the inventory refers to are being demolished. Good for this bridge, but sad for Ohio, this bridge will become much more rare and significant in the context of Ohio's dropping truss bridge population.

Information and Findings From Ohio's Historic Bridge Inventory

Setting/Context

The bridge carries a 2 lane road over a stream in a sparsely developed, rural setting.

Physical Description

The 2-span, 255'-long, pin-connected Pratt thru truss bridge is traditionally composed of built-up compression members and eyebar tension members. It has lattice portals and railings. It is supported on concrete abutments and pier.

Summary of Significance

The 1910 pin-connected truss bridge is a technologically undistinguished, later example of its type/design with no unusual or significant details/features. Earlier and more distinguished examples in the state better represent the significance of the type/design. The not eligible recommendation of the prior inventory remains appropriate.

Pratt trusses were undoubtedly the most popular truss design of the last quarter of the 19th century and continued to be built into the 20th century, although eventually superseded in popularity by Warren trusses. The design, which initially was a combination of wood compression and iron tension members, was patented in 1844 by Thomas & Caleb Pratt. Ohio has three covered bridges that use this combination configuration, but they are all modern reconstructions based on the Pratt patent. The great advantage of the Pratt over other designs was the relative ease of calculating the distribution of stresses. More significantly, it translated well into an all-metal design in lengths of less than 200'. Significant surviving examples of all-metal Pratt trusses mostly date to the last quarter of the 19th century, and they are found with thru, pony, and the less common bedstead configuration. Prior to about 1890, a variety of panel point connections were in widespread use (including bolts, cast-iron pieces, and pins), but engineering opinion was coalescing around pins as the most efficient and constructible. Many of the connection details were proprietary and associated with individual builders or companies, and thus earlier examples are generally taken to be technologically significant in showing the evolution of the design. Later post-1890 Pratt trusses show a progression toward less variation in their details such that by 1900 the design was quite formulaic with few significant differences between the designs of various builders. This marked the end of the pin-connected Pratt's technological evolution and, in fact, it was soon waning and eclipsed in the highway bridge market by more rigid, rivet-connected truss designs, particularly the Warren but also riveted Pratts. The transition to riveted connections, which happened even earlier with railroads than highways, was in no small part due to concerns about stress reversals at the pins under heavier loads and improvements in pneumatic field riveting equipment in the early 1900s. In Ohio, Pratt truss highway bridges, whether pinned or riveted, were almost always built under the auspices of counties and local units of government; the Pratt was not a standard design of the state highway department.

In Ohio, there are 185 Pratt trusses dating from ca. 1874 to 1945 with at least 60 dating prior to 1900 (Phase 1A, 2008). The technologically significant unaltered examples of pin-connected Pratt trusses for the most part date prior to 1900 and have documented or attributed builders and dates of construction and/or significant connection or member details. Later post-1900 examples are less technologically significant. Significant unaltered examples of riveted-connected Pratt trusses date from ca. 1900 to 1915.

Bridge Considered Historic By Survey: No

Divider

Photo Galleries and Videos: Scioto Darby Road Bridge

 
View Photo Gallery
Bridge Photo-Documentation
A collection of overview and detail photos. This photo gallery contains a combination of Original Size photos and Mobile Optimized photos in a touch-friendly popup viewer. Alternatively, Browse Without Using Viewer

View Maps
and Links

Divider
 
Home Top

Divider

About - Contact

© Copyright 2003-2019, HistoricBridges.org. All Rights Reserved. Disclaimer: HistoricBridges.org is a volunteer group of private citizens. HistoricBridges.org is NOT a government agency, does not represent or work with any governmental agencies, nor is it in any way associated with any government agency or any non-profit organization. While we strive for accuracy in our factual content, HistoricBridges.org offers no guarantee of accuracy. Information is provided "as is" without warranty of any kind, either expressed or implied. Information could include technical inaccuracies or errors of omission. Opinions and commentary are the opinions of the respective HistoricBridges.org member who made them and do not necessarily represent the views of anyone else, including any outside photographers whose images may appear on the page in which the commentary appears. HistoricBridges.org does not bear any responsibility for any consequences resulting from the use of this or any other HistoricBridges.org information. Owners and users of bridges have the responsibility of correctly following all applicable laws, rules, and regulations, regardless of any HistoricBridges.org information.

Divider