| Original Location Key Facts |
| Bridge Name | Facility Carried / Feature Intersected | Location | Structure Type | Construction Date / Builder or Contractor |
| Parshallburg Bridge Ditch Road Bridge |
Ditch Road Over Shiawassee River | Parshallburg: Saginaw County, Michigan | Metal Pinned Thacher Through Truss, Stationary | 1889 By: Wrought Iron Bridge Company of Canton, Ohio |
| Technical Facts |
| Rehabilitation Date | Structure Length | Main Span Length | Roadway Width | Main Spans | Approach Spans |
| 1954, 1999 | 140 Feet (42.7 Meters) | 140 Feet (42.7 Meters) | 17.8 Feet (5.4 Meters) | 1 | None |
Remembering the Parshallburg Bridge
Located originally on Ditch Road, this nationally significant bridge was the most significant metal truss bridge in the state of Michigan. Only a few examples of bridges that are similar to Edwin Thacher's 1885 patented Thacher truss configuration remain in the entire country, and as such this bridge, fabricated by the Wrought Iron Bridge Company, was among the most important metal truss bridges in the country. The only other known surviving examples remaining are the West Springbrook Road Bridge in Broadway, VA, to be bypassed and preserved in place, the Ellsworth Ranch Bridge abandoned in rural Iowa, and the Costilla Crossing Bridge, preserved in place in rural Colorado.
The Parshallburg bridge was a through Thacher truss bridge, pin-connected and containing eight panels. It was built in 1889, making it the oldest of its type in the US. The truss configuration alone, which is extremely rare, is nationally significant regardless of construction date. When in its original location, the bridge sat on cobblestone abutments. It is 140 feet long, making it a significant pin-connected truss span length for any truss type. Plaques remained on both ends of the bridge, another rarity for Michigan, and were mounted on top of the portals. The bridge also displayed the unique design characteristics of its builder, including the four-pronged "claw" eyebar detail at the bottom of the hip vertical member.
In 1999, the bridge was relocated to Chesaning, Michigan onto improperly designed piers. In late 2008, the bridge was washed away off its piers and destroyed by flood and ice related debris.
Some parts of this bridge have been saved from the dumpster for the purpose of wrought iron research and preservation training conducted by Vern Mesler.
It Could Have Been Michigan's Greatest Success Story, But Became Michigan's Greatest Failure
The relocation and restoration of this bridge should have been one of Michigan's greatest success stories, and instead this bridge has become Michigan's greatest historic bridge failures. Valuable preservation money and community support were wasted, and resulted in the destruction of one of Michigan's most important transportation-related historic resources.
This bridge should have either been preserved in its original location upstream where it was safe from floods (and as a group of local residents had originally wanted), or been relocated onto piers that were properly designed for expected flood levels.
The engineers who designed the so-called relocation and restoration of this bridge failed to design the substructure correctly, placing it on piers far too low, something obvious by simply looking at the river's previously observed flood levels. These engineers failed to properly engineer the relocation project, and for this reason, and this reason alone, was this bridge washed away and destroyed. Blame is placed solely upon these engineers, and not the city of Chesaning, and not even the flood itself. Determining the flood levels prior to designing a bridge is supposed to be basic engineering practice.
Normally, engineers are overly paranoid when it comes to flood levels. Sometimes engineers demand the demolition of a historic bridge that has stood safely for a 100 years, like the Blue Rock Road Bridge, claiming it does not meet 100 year flood levels, even though it has stood for 100 years. Given this normal paranoia level among engineers in general, it suggests how unskilled the engineers who designed the relocation of the Parshallburg Bridge really were. The flood that occured and washed out the Parshallburg Bridge was not unusual, since local citizens had protested since the historic bridge was put into place that the bridge was too low to the river. Even if the engineers were inept, at least a simple public dialog with local citizens prior to the relocation of this historic bridge could have still prevented this disaster.
To this day, it remains unclear to HistoricBridges.org how an engineering company can get away with a failure of this magnitude. The company should have been forced to pay for a complete, exact replication of this bridge. Apparently, this engineering company is still in business, and following this bridge's collapse, still did the Shiawassee River restoration next to the site of the bridge's destruction. They apparently were selected because the project was a let bid, and as such they could not pick and choose who did the work. It is good that this engineering company is doing something like a river restoration now instead of bridge work. A company that cannot analyze the flood levels of a river, a basic process, should not be trusted to design bridges, where safety requirements demand that mistakes are not made.
Information and Findings From Michigan's Historic Bridge InventoryDiscussion of Bridge The Parshallburg Bridge is the oldest surviving Thacher truss in the United States. Edwin Thacher developed and patented this hybrid truss in 1883. The Wrought Iron Bridge Company of Canton, Ohio, a prolific bridge builder in Michigan and the mid-west, was the builder of the Parshallburg Bridge. The eight-panel structure has a length of 140 feet and an overall deck width of 17.8 feet. It stands on extensive abutment of rubble fieldstone, and is now closed to traffic. Discussion of Surrounding Area The Parshallburg or Ditch Road Bridge is a single-span, Thacher metal through truss bridge. Engineers who have evaluated the structure's condition believe the metal is wrought and cast iron because of the structure's relatively good overall condition. The eight-panel structure has a length of 140 feet and an overall deck width of 17.8 feet. The bridge stands on extensive abutments of rubble fieldstone. Now closed to traffic, it carries Ditch Road across the Shiawassee River at the unincorporated hamlet of Parshallburg, three and one-half miles south of Chesaning. Each portal displays a cast-iron plaque containing the legend "WROUGHT IRON BRIDGE CO., BUILDERS, CANTON, OHIO." The Parshallburg or Ditch Road Bridge is the only Thacher truss highway bridge in Michigan and the older of only two known surviving examples of this truss type in the United States. The bridge is one of only a very small number of surviving examples in Michigan of the work of the Wrought Iron Bridge Company, one of the most important nineteenth-century, Midwestern bridge-fabricating concerns.
Above: Photo of bridge in original location. Bridge Considered Historic By Survey: Yes |
