GREEN BAY, Wis (WSAU-Wheeler News) State transportation officials said a "highly unusual" combination of factors caused a high Interstate bridge in Green Bay to sag last September. The D-O-T released a summary yesterday of its final report of the incident, in which a support pier went down two-feet and caused part of the Leo Frigo Memorial Bridge on I-43 to sag.
No one was hurt at that time.
Minor corrosion was also found on 17 other piers. It took two-and-a-half months to make the repairs, and the D-O-T said the final cost was $10-million -- much less than the $18-to-20-million that was originally projected.
Officials said soil conditions caused the foundation of steel piling to corrode and buckle. Those factors included a porous fill of fly ash in the upper levels of the soil -- and the water and soils surrounding the piling had high amounts of chlorides. Project manager Tom Buchholz tells WLUK TV in Green Bay it was amazing the bridge still stood after the sagging incident. In his words, "We're very, very lucky."
As part of the repairs, crews installed probes that monitor rust and corrosion, and pilings at eight spots on the bridge will be tested every two years.