John Puryear Bridge Safety Shield Installed
Paducah, KY (October 17, 2005) – A bridge maintenance crew expects to complete the installation of a safety shield on piers of the John Puryear Bridge on Paducah’s Southside in the next two weeks. The sheet metal shield is being attached along the top of the bridge pier caps to catch any additional concrete that may chip off the diaphragm panels above the piers in the future.
Kentucky Department of Highways District One Bridge Engineer Harold Gibson says only a few chips of concrete appear to have fallen from the diaphragm panels since concrete was initially reported falling from the bridge in early April.
“We’ve seen little evidence of additional concrete falling from the panels since our initial inspection. The shields we are installing now are designed to catch and prevent concrete that might break loose from reaching the ground while still allowing us access to inspect the panels,” Gibson said.
The diaphragm panels are designed to prevent movement of the beams that support the bridge deck. Inspectors determined that spalling of concrete was isolated to the diaphragm panels above the pier caps and observed that mid-beam diaphragm panels or stiffeners have had no visible problems.
After a Paducah woman filed a report with McCracken County Deputies indicating she had been struck by a piece of concrete while walking beneath the structure, a neighbor said pieces of concrete had started falling from the bridge a day or two earlier, but he did not report it to transportation officials.
Transportation Cabinet personnel used warning tape and traffic barrels to keep pedestrians away from the pier caps until the problem could be evaluated. Nearly three months of investigation confirmed the initial finding that the John Puryear Bridge is structurally sound.
“The safety of the John Puryear Bridge is our priority,” said Chief District Engineer Ted Merryman. “Our research found that some other bridges of similar design around the state have also shown evidence of concrete chipping off where the pier cap diaphragm panels meet beams on the substructure.”
Kentucky Transportation Cabinet design engineers are evaluating modifications for future structures of similar design based on experience gleaned during the investigation.
Cost of fabricating and installing the safety shield is estimated at about $50,000. Once completed, engineers will evaluate the effectiveness of the safety shield and determine if additional modifications are needed.
The bridge is normally given a detailed inspection every two years. Gibson says while there will be no formal accelerated inspection schedule for the John Puryear Bridge inspectors will be making informal inspections from time to time.
“This problem appears to have developed as weather warmed up in the spring and is likely due to freezing and thawing. We’ll be watching the bridge closely as temperatures start to rise next spring,” Gibson said. “We’ll continue to do that until we determine that there is no longer a problem.”
Installation of the protective shield will allow highway department crews to remove warning barrels, caution tape, and construction fencing beneath the structure.
The 1200 foot span carries KY 1956/John Puryear Drive across Old Benton Road, Bullard Street, Cook Street, an alleyway, the P & L Railroad and a section of Old Clarks River Road that is now a frontage road.
About 15,000 vehicles per day travel over the bridge on John Puryear Drive (KY 1954) at the main southside intersection with Clarks River Road, Irvin Cobb Drive, and Wayne Sullivan Drive on the I-24 Business Loop.
The bridge was let for bid in late 1996 and construction was completed in 1998.