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Repair of Traffic-Impacted Box Beam Bridge. Hawkins Road Crossing Interstate 94 in Michigan. January 1983: Impact Breaks 7 Strands. March 1983: Second Impact Breaks 2 More Strands. The Original Shop Drawings. Repair Approach. Use District Maintenance Crew Repair Each Strand Using
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Repair of Traffic-Impacted Box Beam Bridge Hawkins Road Crossing Interstate 94 in Michigan
Repair Approach • Use District Maintenance Crew • Repair Each Strand Using • Splice Chuck Coupler • Hex Splice Sleeve and • Two ¾ inch Diameter A449 Rods (one right hand thread and left hand thread on the other to allow tensioning)Hardware cost is about $175 per strand but delivery is a long five months
Tensioning Computation • Tensioning allowed for losses that had occurred during the 25 year life of the bridge
Tensioning was accomplished in 4 passes from the inside to the outside of the beam
Deflecting Beams • A preload was used so that the repair-concrete would be in compression after the preload removal
Four Months After Completion of First Repair: • Bridge was hit for the third time
Most of the splices done earlier were intact, indicating a durable repair
The damage this time was 19 of the 25 strands of the fascia beam, 7 strands of the first interior beam and 4 strands of the second interior beam. • The repair involved replacement of the fascia beam with a solid concrete beam and repair of the interior beam using the successful approach of the earlier repair.
Post Script • Shortly after the second repair was completed the bridge was hit a fourth time. This time it only suffered a nick in the solid fascia beam.