Honor Award – Horner & Shifrin, Inc., St. Louis

Firm Name: Horner & Shifrin, Inc., St. Louis

Project: S. Sprigg St. Bridge Over Active Sinkholes

Client: City of Cape Girardeau, MO

This complicated project is an outstanding example of interdisciplinary cooperation, application of bridge engineering concepts, thoughtful planning and methodical construction management, which resulted in re-opening of a key transportation route. Sinkholes caused a collapse of the north bridge approach and one pile was holding up the north bent.  Sinkhole activity also threatened the south bent.  To design this three span, 385’ long concrete girder bridge, engineers drilled 134 soundings to top of rock and two test pits to define karst features.  Eighty rock cores were advanced for foundation design.  Engineers considered footings, micropiles, drilled shafts and piles and determined spread footings provided optimal structural redundancy.  During construction open excavation allowed for inspection of the rock.  Sinkhole remediation was completed to mitigate safety concerns and reduce offsite consequences during flood events.