MINNESOTA ARCHITECTURE - HISTORY INVENTORY FORM

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1 Identification Historic Name Bridge Current Name Bridge Field # Address N/A CSAH 17 over Minnesota River City/Twp Delhi County Redwood Legal Desc. Twp 113 Range 36 Sec 3 QQ NWSW USGS Quad DELHI UTM Zone 15N Datum NAD83 Easting Northing Property ID (PIN) SHPO Inventory Number Review and Compliance Number Form (New or Updated) Updated Description Linear Feature? No HPC Status: Unknown Resource Type Structure Architect/Engineer Lawrence Henry Johnson Style No Style Construction Date 1910 Original Use Transportation Current Use Transportation Description Bridge is a Parker through-truss bridge that carries CSAH 17 over the Minnesota River between Redwood and Renville Counties. The bridge is located in Delhi Township, Rock County, Minnesota, 1.4 miles north of the junction with CSAH 9. The one-lane bridge has a north-south alignment. CSAH 17 is a gravel road. The bridge substructure consists of abutments, wingwalls, and two piers. The south abutment is reinforced concrete with 12 foot long wing walls that angle out from the bridge. In 1961, the south abutment was repaired by adding a center piling and pouring a reinforced-concrete abutment around the two original pilings (Redwood County Highway Department 1961). The abutment has 12 foot long wing walls that angle out from the bridge. The north abutment has a concrete block facing over the original abutment and wing walls (MnDOT 2010). There are two piers, one on either end of the bridge, that sit in front of the abutments, and each is comprised of two filled steel caissons. These piers support the main span and the ends of the approach spans. The inclined end posts of the main span are bolted into the top of each caisson. The three-span superstructure consists of a seven-panel Parker through-truss main span and two short steel beam span approaches, one on either end of the main span. The main span has a length of 170 feet, and the approach spans are 10.5 feet each, for a total structure length of 191 feet. The pin-connected truss main span has a maximum vertical clearance of 8.4 feet. The lower chord of the truss is connected to the vertical posts and the floor beams by eye bar pin connections. The latticed vertical posts are riveted to the web of stringers. The truss is braced by metal diagonals and bracing ties. The end posts and top chord built-up members are of riveted construction and are comprised of two channel sections with a top plate and lattice connecting the bottom flanges of the channels. The vertical posts are connected to the top chord of the truss by pin connections. There are nine rolled steel stringers located under the main span that support the deck, as well as nine steel beams in each approach span. Ten rolled steel floor beams are evenly spaced perpendicular to the bridge underneath the stringers. Bottom lateral bracing is found between each floor beam. The deck is 15.7 feet wide and is comprised of two layers of timber planks; the bottom layer runs perpendicular to the bridge while the top wearing surface runs parallel with the bridge. A raised wood curb runs the entire length of the bridge on both sides with evenly spaced scuppers. The railing is comprised of angle iron posts and two horizontal angle iron rails with strap metal lattice between the rails. The railing is bolted to the vertical truss members. Intermediate posts between the vertical posts extend from the bottom chord to support the railing. Integrity - Bridge remains in its original location, in its historic use, and retains its setting. Therefore, the bridge retains good integrity of location and setting. The Registration Requirements for steel bridges as identified in the Iron and Steel Bridges in Minnesota MPDF state that the superstructure is the most important feature of bridges in this property type and that for a

2 bridge in this property type to be eligible for the National Register, the superstructure itself must be in substantially original condition, including the connections and the composition and configuration of individual composite members (Quivik and Martin 1988:F-8). Despite over 100 years of service, few alterations to the superstructure have occurred. In 2004, the wood plank deck was replaced in-kind. At some point in time, lateral cross bracing below the deck was also replaced in-kind. These repairs have been made as part of ongoing maintenance to the bridge to continue its historic use and do not substantially detract from the design, materials, and workmanship of the original superstructure. The registration requirements also state that the substructure can be altered or replaced provided that the new elements are of such scale and composition that they do not overwhelm or otherwise detract from a clear visual impression of the iron or steel form of the superstructure and its function (Quivik and Martin 1988:F-8). Bridge has altered abutments; the north abutment has a new concrete block facing, while the south abutment was replaced in However, neither abutment has been altered in such a way that would detract from the visual impression of the superstructure. Therefore the substructure of Bridge retains sufficient integrity of design, materials, and workmanship to convey its significance. While the bridge retains its historic elements, many of the bridge s members are in poor condition. Paint failure has led to substantial rust accumulation throughout the structure. Flooding, ice, and impact damage from flooding and vehicles has also left many railings, stringers, and vertical posts bent and warped. Fracture Critical inspection reports highlight deficiencies such as a vertical crack running the entire height of the north abutment, corrosion and pack rust, expansion bearings that are at their expansion limit and do not appear to be functioning, and potential lower chord compression. While the bridge is in a slightly deteriorated condition, the bridge retains sufficient integrity of design and workmanship of the bridge and the condition of the bridge does not detract from its visual impression as a Parker through-truss bridge. The bridge therefore, retains its integrity of feeling and association. Overall, the bridge retains sufficient integrity to convey its historic significance. EVALUATION AND ANALYSIS Historical Context Historic Iron and Steel Bridges in Minnesota, Historical Narrative Bridge is located in Delhi Township, which is located in the northern portion of Redwood County. Bridge is known locally as the Gold Mine Bridge for its proximity to an old gold mining camp located on Gold Mine Lake, approximately 0.8 miles west of the bridge. While there is no builder s plate to confirm its construction date and MnDOT records say it was built in 1910, entries in the Redwood County Commissioners Record books confirm that Bridge was constructed in 1903 (Quivik and Martin 1988:E- 25). Bridge was constructed by Lawrence Henry Johnson of Minneapolis (Gardner 2008). Johnson was born in Germany in 1862 and moved to the United States in 1875 with his parents. He lived in New York and Michigan before arriving in Minnesota in 1883 or After moving to Minnesota, Johnson worked for the Minneapolis Bridge Company, the Milwaukee Bridge and Iron Company, the Wrought Iron Bridge Company, and the Wisconsin Bridge and Iron Company (Quivik and Martin 1988:E- 11). In 1905, Johnson formed the Hennepin Bridge Company, which was active in a region extending from Wisconsin to Montana (Quivik and Martin 1988:E-11). Lawrence Johnson was also active in politics. From 1901 to 1910, Johnson served as a Republican legislator in the Minnesota House of Representatives, representing District 43 (Hennepin County), serving as the Speaker of the House from 1907 to 1908 (Minnesota Legislative Reference Library 2013). During this period Johnson listed his occupation as Bridge Contractor and Engineer; President, The Hennepin Bridge Company (Minnesota Legislative Reference Library 2013). According to Quivik and Martin, Bridge is the only surviving bridge in Minnesota known to have been designed by Johnson (Quivik and Martin 1988:E-11). Another Minnesota bridge that is known to have been built by the Hennepin Bridge Company, but not designed by Johnson, is the single-span camelback Waterford Bridge (Bridge L3275; DK-WTR-005) located

3 near Northfield, Minnesota (Gardner 2008:63). Bridge s Parker through-truss design is unique among iron and steel bridges in Minnesota. By 1880, the Pratt throughtruss was the standard structural type used for long span bridges in Minnesota. After 1911, it was superseded in popularity by the Warren truss, which became the most widely used truss in the state (Quivik and Martin 1988:E-6). Bridge was built prior to 1911, when Pratt trusses were the prevailing truss design for bridges. The Parker truss is a derivative of the Pratt truss and was intended for use on spans between 40 and 250 feet (HAER 1976). As Bridge has a main span length of 170 feet, either a Pratt or a Parker truss would have worked in this location as both were able to span distances of up to 250 feet (HAER 1976). While a Parker truss was slightly more complicated to build, it required less material than a Pratt truss, so it was a logical choice (Bridgehunter.com 2012). Few records exist to document changes to Bridge over time. A set of plans prepared by the Redwood County Highway Department in 1961 depict repairs to the south abutments that were made during the winter of This included adding a center piling and pouring a reinforced-concrete abutment around the two existing pilings (Redwood County Highway Department 1961). A MnDOT Bridge Inspection Report from 2012 indicates that a concrete block wall has been added to the north abutment (MnDOT 2012c). This wall is located directly in front of the original concrete abutment; however no record of when this wall was built has been found. The same inspection report also indicates that the timber deck on the bridge was replaced in-kind in 2004 (MnDOT 2012c). Photos from a 2010 Routine and Fracture Critical Inspection report show that lateral cross bracing under the deck was replaced in-kind, though the date when this repair was done is not known (MnDOT 2010). Significance According to MnDOT s Historic Bridge List, Bridge has been previously determined eligible for listing in the National Register of Historic Places (NHRP) under Criterion C, for both its typology and its association with a significant builder (MnDOT 2013). Bridge is significant within the historic context Historic Iron and Steel Bridge in Minnesota, The Iron and Steel Bridges in Minnesota Multiple Property Documentation Form (MPDF) states that several engineers, fabricators, and contractors are important to the history of Minnesota bridge building; therefore bridges associated with them have significance (Quivik and Martin 1988:F-7). Correspondingly, Registration Requirement 5 of the Iron and Steel Bridges in Minnesota MPDF provides for a bridge to be eligible for the NRHP under Criterion C if it was built by an important Minnesota bridge builder. Lawrence Henry Johnson is listed under Registration Requirement 5 as one of the most active and important late 19th and early 20th century bridge builders based in Minneapolis. Bridge is the only surviving bridge in Minnesota known to have been designed by Johnson. Therefore, Bridge has significance under Registration Requirement 5 of the Iron and Steel Bridges in Minnesota MPDF for its association with Lawrence Henry Johnson. Bridge has additional significance under Registration Requirement 8 of the Iron and Steel Bridges in Minnesota MPDF as an example of a through truss bridge which is not a Pratt or (after 1911) Warren Truss (Quivik and Martin 1988:F-9). The most common 19th and early 20th century truss bridges built in Minnesota were Pratt trusses; Warren trusses were also common in the early 20th century (Quivik and Martin 1988:F-6). Therefore, through-truss bridges from this period that utilize other truss designs are very rare and represent an important design experiment or design solution to an unusual problem (Quivik and Martin 1988:F-9). Bridge is a rare example of a Parker through-truss bridge in Minnesota. Constructed during the period in which the Pratt truss was the most widely used truss type in Minnesota, the Parker design of Bridge was a unique design solution for crossing the wide Minnesota River. The use of a Parker design allowed for the construction of a single 170 foot main span over the river, thus avoiding the need to construct multiple spans, and allowing the main channel to remain unimpeded. While its Parker truss design was slightly more complex to construct, it required less material than a Pratt truss, thus Bridge embodies a unique, more efficient design solution. Therefore, Bridge has significance under Registration Requirement 8 of the Iron and Steel Bridges in Minnesota MPDF as a rare design type within Minnesota. Recommendation Bridge is recommended as eligible for the NRHP under Criterion C, within the statewide historic context Historic Iron and Steel Bridges in Minnesota, Bridge meets Registration Requirement 5 of the Iron and Steel Bridges in

4 Minnesota MPDF. Registration Requirement 5 states bridges are eligible for the NRHP under Criterion C if they were Built by an Important Minnesota Bridge Builder (Quivik and Martin 1988:F-9). Bridge was built by Lawrence Henry Johnson who is identified in the historic context Historic Iron and Steel Bridges in Minnesota, as an important Minneapolisbased bridge builder (Quivik and Martin 1988:E-11). Bridge is significant as the only known surviving bridge in Minnesota designed by Johnson and is therefore recommended as eligible for the NRHP under Criterion C, Registration Requirement 5 of the Iron and Steel Bridges in Minnesota MPDF, for its association with Johnson. Additionally, Bridge meets Registration Requirement 8 of the Iron and Steel Bridges in Minnesota MPDF, which states that bridges can be eligible for the NRHP if they are A Through Truss Bridge Which Is not a Pratt or (after 1911) Warren Truss (Quivik and Martin 1988:F-9). Bridges that are not Pratt or Warren trusses are very rare and represent an important design experiment or design solution to an unusual problem (Quivik and Martin 1988:F-9). Bridge is significant for its unique design solution. Its Parker through truss design allowed for the construction of a single main span across the Minnesota River, eliminating the need for multiple spans that would have created obstructions in the river channel. The Parker truss is also a unique design solution in that it required less material to construct compared to a Pratt truss, which was the prevailing truss design used for bridges in Minnesota prior to The bridge retains sufficient historic integrity to convey its significance as a Parker through truss bridge. Therefore, Bridge is recommended as eligible for the NRHP under Registration Requirement 8 of the Iron and Steel Bridges in Minnesota MPDF as a unique and rare example of the Parker through truss bridge built in Minnesota. The period of significance for Bridge is 1903, corresponding with the year the bridge was constructed. Sources Bridgehunter.com 2012 Parker Truss. Electronic document, accessed September 30, Gardner, Denis 2008 Wood, Concrete, Stone, and Steel: Minnesota s Historic Bridges. University of Minnesota Press, Minneapolis, Minnesota. Historic American Engineering Record (HAER) 1976 Trusses: A Study by the Historic American Engineering Record. National Park Service, Washington D.C. Minnesota Department of Transportation [MnDOT] 2006 Fracture Critical Bridge Inspection Report for Bridge CSAH 17 over the Minnesota River, Delhi Township, Redwood County. Bridge Safety Inspections Bridge Office, Minnesota Department of Transportation, Oakdale, Minnesota Routine and Fracture Critical Bridge Inspection Report. Minnesota Department of Transportation, MnDOT Bridge Office, Oakdale, Minnesota. 2012a MnDOT Structure Inventory Report Bridge ID Minnesota Department of Transportation, St. Paul, Minnesota. 2012b Local Historic Bridge Report Bridge Number Minnesota Department of Transportation, St. Paul, Minnesota. 2012c MnDOT Bridge Inspection Report: Bridge Minnesota Department of Transportation, St. Paul, Minnesota Historic Bridge List. Electronic document, accessed September 20, Minnesota Legislative Reference Library 2013 Johnson, Lawrence Henry. Electronic document, accessed September 12, Parsons Brinckerhoff [PB]

5 Routine and Fracture Critical Bridge Inspection Report. Prepared for Minnesota Department of Transportation Bridge Office. Prepared by Parsons Brinckerhoff, Minneapolis, Minnesota. Redwood County Highway Department 1961 Bridge No 17DE7 South Abutment Repair. On file at the Redwood County Highway Department, Redwood Falls, Minnesota. Quivik, Fredric L. and Dale L. Martin 1988 National Register of Historic Places Multiple Property Documentation Form: Historic Iron and Steel Bridge in Minnesota, Prepared by Renewable Technologies, Inc. On file at State Historic Preservation Office, St. Paul, Minnesota. National Register Status Determined Eligible Consultant's Recommendation of Eligibility Eligible - Individual Prepared By Kelli Andre Kellerhals The 106 Group Ltd. Date Surveyed 10/3/2013

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