1. Repair of Traffic-Impacted Box Beam Bridge Hawkins Road Crossing Interstate 94 in Michigan

2. January 1983: Impact Breaks 7 Strands

3. March 1983: Second Impact Breaks 2 More Strands

4. The Original Shop Drawings

5. 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

6. Splice Chucks

7. Cutting Damaged Strands

8. Installing Splice Chucks

10. Drilling for Void Form Attachment

11. Installing Turnbuckles

12. Tensioning Rods with Stain Gauges

13. Installing Tensioning Rods

14. Strain Gauge

15. Tensioning Computation  Tensioning allowed for losses that had occurred during the 25 year life of the bridge

16. Tensioning

17.  Tensioning was accomplished in 4 passes from the inside to the outside of the beam

19. All Strands Repaired

20. Deflecting Beams  A preload was used so that the repair-concrete would be in compression after the preload removal

21. A New Bridge Opening Height

22. Preparation for Form Attachment

23. Preparation of Form

24. Form Release Agent Applied

25. Form Installation

27. Creating Vibration Access

28. Final Deflection Verification

29. Concrete Delivery

30. Concrete Quality Control

32. Placing of Concrete

34. Vibration of Concrete

35.  Repair Completed!

36. Four Months After Completion of First Repair:  Bridge was hit for the third time

37.  Most of the splices done earlier were intact, indicating a durable repair

38.  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.

39. 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.