Increased moisture and the elimination of drainage improvements from a resurfacing project two years ago contributed to pavement heaves that affected the Anthony Wayne Trail in January, according to a report completed this week.
The report from TTL Associates, Inc., of Toledo, determined that Miller Brothers Construction, the contractor for the resurfacing project, was not to blame for the rough driving conditions that developed during a cold snap last winter, Hussein Abounaaj, the city's commissioner of engineering services, wrote in a May 4 memorandum to Jay Black, Jr., the city's chief operating officer.
The bumps were caused by frost heaves affecting concrete slabs underneath, with which Miller Brothers' work was not involved.
Bumps formed in the Trail at the locations of joints in concrete slabs below the surface that once had been the pavement before the roadway was resurfaced with asphalt. During February and March, the bumps gradually settled, leaving cracks behind.
During the summer of 2002, Miller Brothers scraped away the surface of the asphalt paving and replaced it.
The frost heaves were worse last winter than they were before the repaving project, Mr. Abounaaj said, because:
●An irrigation system was added in the Trail's median just before the project, which may have added moisture under the pavement.
●Rainfall after the top 3 inches of old pavement were scraped away may have further increased the amount of moisture trapped underneath.
●As a cost-cutting measure, plans to include curbs, subsurface drains, and other drainage improvements in the project were dropped. Eliminating drainage reduced the Miller contract from $3.8 million to $1.9 million.
Mr. Abounaaj recommended that any cracks in the pavement be sealed to minimize the amount of trapped moisture.