TWM provided engineering services for IDOT’s first successful bridge slide in Pocahontas, IL. A 108’ single-span superstructure was constructed on temporary abutments and slid laterally 39’ onto permanent abutments. Temporary abutments consisted of driven H-piles with pre-cast concrete slabs on top of a pair of 33” rolled beams. H-piles had to be driven offset of center of the temporary abutments for clearance to power lines, which created significant differential deflections as the superstructure was built. TWM accurately predicted these deflections, thereby keeping distortion of the superstructure within tight specification tolerances. Keller and TWM were given the Illinois AGC Contractor of the Year Award for their work on this project.

Scope of Work

  • Services included calculations and details for temporary abutments, lateral slide system, geometry control plan, and vertical jacking plan


IDOT District 8 / Keller Construction


Pocahontas, IL


  • TWM’s calculations kept superstructure within tight specification tolerances