Delta Covered Bridge, Delta Iowa
An arsonist set fire to the center of bridge on Wednesday September 3rd, 2003, and the bridge was destroyed. The county had just been approved for a $150,000 grant to improve the bridge and move it back to its original location. The arsonist struck exactly 1 year after the Cedar Bridge in Madison County was destroyed by arson.
Not only is this the last remaining covered bridge in Keokuk County, the Delta Covered Bridge is one of the few such bridges remaining in Iowa. The Burr Arch Truss construction of this bridge is rather unique, and is the only one of its kind built in Iowa. This was a common type of bridge but few remain, probably due to the failure of the wooden tension members of the bridge.
During the mid-1860s, the County Board of Supervisors, under Chairman Maxon Randall, selected this site for a bridge to span the North Skunk River. The contract to build it was awarded to Joseph Merrifield and, James Harlan. Construction of the bridge was begun in 1867 and completed in 1869 for $1,080.00.
A roadside park and picnic area is maintained at the south end of the bridge on a wooded sloping hillside. The bridge is open to foot traffic only.
Bridge Description
The Delta Covered Bridge of Keokuk County remains essentially in its original condition, although the North Skunk River which it spans is seriously undermining its piers.
The main structural members of the bridge are of locally sawed oak and red elm, whereas the siding and roof covering are of 1" x 12" pine, the Shingles cedar. The northeast pier is as originally built, and is built up from random size pieces of limestone. The southwest pier is made up of two concrete-filled steel caissons, apparently placed after the river destroyed the original stone pier.
Dimensions of the bridge are 80 x 12' with 50' and 40' approaches (added after initial construction as the river widened) at either end. The basic structure of the bridge is a Howe Truss modified by the addition of an arch. This combination is commonly referred to as the "Burr Plan" or a "Burr Truss". The arch carries most of the compression load of the bridge and roof. The tension members on the outside bottom of the truss are oak and are pinned with a tenon-type joint to transfer the load across the splice joints. The roof framing carries none of the floor load.
