This project was let by Illinois Department of Transportation (IDOT) as an extension of the reconstruction of the I-57/I-70 Interchange being designed by Lochmueller Group (Lochgroup). By compressing the design schedule from 18 to 12 months and proposing changes to the construction phasing, Lochgroup was able to save IDOT approximately $1.2 million.
The Little Wabash River Bridges are dual 5-span (83’-3”; 83’-3”; 126’-0”; 83’-3”; 83’-3”) prestressed structures. Lochgroup developed the final design plans for the replacement structures consisting of a Bulb-T superstructure supported on reinforced concrete piers and abutments on a 0° skew with expansion joints at each end. The total length of each structure is 465-foot, back-to-back of abutments and the clear roadway width on each structure is 44 feet. The bridges were built using staged construction and cofferdams. The bridges also incorporated IDOT’S new Bridge Smoothness Criteria for decks. The structure is in Seismic Performance Zone 2, requiring a detailed seismic analysis. The high potential for scour resulted in a complex structure design.
The project also involved approximately 1,725 feet of roadway work that incorporated a profile grade raise of 20 inches to accommodate the deep Bulb-T beams. Design efforts included design of the vertical alignment, drainage calculations, quantity calculations, and final plans and special provisions.