Mill Creek Bridge

Mill Creek Bridge

Cherokee County, IA

Cherokee County wanted to replace an existing high truss bridge over Mill Creek that was on a poor horizontal alignment. The existing bridge had sharp curves on both approaches and had a posted weight limit. Previous preliminary plans had a new bridge on a straight segment between two horizontal curves. Transitions for super-elevation into and out of the curves still made the horizontal alignment marginal in terms of minimum design parameters.

The replacement bridge was designed on a horizontal curve with super-elevation built into the bridge cross section. The length of curve was increased to allow the required super-elevation to fall within required design standards. An IDOT standard three span 226′ x 30′ pre-stressed concrete beam bridge was modified and adapted to fit the horizontal and vertical alignment. The spacing of the straight line beams was adjusted in each of the three spans as were the angles of the two abutments to fit the superstructure to the curved footprint of the bridge deck.

The adaptation and modification of a standard design allowed the contractor to use readily available standard beams. The substructure-piers and abutments-were also modifications of standard plan details allowing use of commonly used materials. Once constructed, the bridge was used to move material from a cut section of the south side of the bridge to the approach fill on the north side of the waterway. The previous high truss was retained as a historical structure. A canoe access and parking area was constructed along the south bank of Mill Creek.

Public Works

  • Alta Wastewater Treatment Plant

  • Cherry Street Ramp

  • Fairmont Water Treatment Plant

  • Goodhue Water Tower

  • Humboldt Pavement Management Study

  • Kingsley Wastewater Treatment

  • Lawton Water Treatment Plant

  • Madison Lake Regionalization

  • Mill Creek Bridge

  • Moville Comprehensive Plan

  • Sample Street

  • Second Street Ramp

  • Sibley Parkway

  • Sloan Wastewater Treatment Plant

  • South Front Street Reconstruction

  • Sumner Avenue Town Square

  • Trunk Highway 60 Downtown Reconstruction and Improvements

  • US Highway 14 Roundabout

  • US Highway 20

  • US Highway 59

  • West Lakeshore Drive