Year constructed: 1920
Bridge type: Pin-Connected Parker Through Truss
National Register of Historic Places status:
Listed
Length: 192.0 feet
Width: 202 feet
Spans: 17.1
FHWA: 238030
Jurisdiction: Mahaska County
Location: County Road G13 over the North Skunk River, 1.8 miles northeast of New Sharon, Section 7, T77N-R15W (Union Township)
Details
After a personal investigation had been made of the site for the bridge over North Skunk River, between the counties of Poweshiek and Mahaska, the joint meeting was called at the rooms of the New Sharon Savings Bank at New Sharon, Iowa, to further discuss the matter," reported the Mahaska County Clerk in February 1919. The bridge that the two counties were contemplating would span the North Skunk River on the county line. The Iowa State Highway Commission bridge department had drawn up a 200-foot-span rigid-connected truss for the crossing late the previous year. Using the ISHC drawings, the two counties let the project out for competitive bids that spring.
The contract was let to the Iowa Bridge Company of Des Moines for a 200'x18' pin connected high truss with concrete floor, steel tubular piers, and wood approach spans, complete as per plans, for a total cost of $50,000, $40,000 of which was to be paid jointly by Poweshiek and Mahaska counties and the balance of $10,000 to be paid by citizens of New Sharon and vicinity. Iowa Bridge used a superstructure fabricated by the American Bridge Company to build the bridge, completed later in 1919. The truss carried regional traffic in this location until it was replaced by another structure on U.S. 63. The 1920 truss was later dismantled and moved south one mile to its present location, where it was re-erected on concrete abutments. It now carries county-road traffic in unaltered condition.
Why the North Skunk River Bridge was built using pinned connections instead of the riveted connections as drawn by the highway commission is not known, but it probably relates to cheaper costs for the former structural type. Today the bridge is distinguished as the longest example of its type. The subsequent move has diminished its historic significance somewhat, although in truth the new locations is only a mile form the original and both cross the North Skunk River. A well-preserved, long-span example of what - through more recent attrition - has become a relatively uncommon bridge type, the North Skunk River Bridge is an important highway-related resource [adapted from Fraser 1992].