Director of Engineering
City of Nashville, Tennessee
Member, UPROW Technical Committee
The Construction Practices Subcommittee was asked by the Utility and Public Right-of-Way (UPROW) Technical Committee to research available documents related to pavement degradation and to identify good examples. The request initiated from the report, "Recommendation to Establish a New Professional/Education/Technical Committee for Utility and Public Right-of-Way Issues," prepared by the Utility and Right-of-Way Task Force, dated April 13, 1998.
The documents were to be evaluated on several factors starting with the assessment of the long-term maintenance impacts on existing pavements due to cuts made by utility contractors. The evaluation also looked into the cost impacts associated with the accelerated maintenance associated with the pavement cuts and recommendations for detailed specifications and drawings to improve the life of the patch.
This report documents the process the subcommittee followed to gather the information and to assess and evaluate the data and the results of our findings.
Requests were made to local governments and other agencies around the United States and Canada for samples of reports dealing with pavement degradation. The subcommittee also used APWA's InfoNOW feature on their webpage to reach out to the right-of-way community. A total of ten documents were received and evaluated. Some of the submittals included detailed structural analysis, drawings, pictures, specifications, codes and cost estimates. Each report was reviewed and evaluated by members of the subcommittee.
Analysis and Evaluation
Prior to receiving the reports, the committee members developed a table of criteria to use to evaluate the information and data. These criteria included the following factors:
Long-term performance of pavement systems and the effect of cuts depend on water infiltration, quality of materials, and construction practices. Rainfall or snowmelt can infiltrate pavement at the junction of the patch and the existing pavement section. Water weakens the pavement layers and reduces the life of the pavement section or patch. Ice compounds the problem. Poor construction techniques can damage the area adjacent to the cut and further degrade the patch and surrounding pavement. Likewise, if the quality of materials used to repair the cut is less than equivalent to the existing pavement section, problems will likely occur. And to compound this issue, all of these factors are interrelated to each other, which was not specifically addressed in the reports.
Other significant findings include:
The City of Seattle submitted the report entitled "Impact of Utility Cuts on Performance of Seattle Streets." The report was prepared by Nichols, Vallerga, and Associates, an engineering firm specializing in pavement and materials. This report is a good resource in several areas evaluated by the committee. In fact, this report had the overall highest score of all the reports submitted. In particular, the areas of fee schedule development, field testing, and references were very informative. This report provides a detailed comparison of fee schedule development and cost analysis in several cities.
The City of Cincinnati submitted the report entitled "Impact of Utility Cuts on Performance of Street Pavements." The city and APWA sponsored the report. Andrew Bodocsi, Prahlad D. Pant, Ahmet E. Aktan, and Rajagopal S. Arudi of the Cincinnati Infrastructure Institute Department of Civil & Environmental Engineering, University of Cincinnati, prepared the report. This report provides a thorough list of references, fee schedule development, and field testing. Field testing considers the measure and computed deflections at studied sites, seasonal correction coefficients, lateral damage, and traffic load influences. Data collected is displayed with graphs and charts.
The City of Nashville/Davidson County submitted the report entitled "Evaluation of the Effects of Pavement Excavations and the Development of a Street Damage Restoration Fee Schedule for the Metropolitan Government of Nashville and Davidson County." Infrastructure Management Services (IMS) prepared the report. This report serves as a good resource in the areas of fee schedules, cost analysis, field testing, and documentation. Fee schedule development and cost analysis parameters considered items such as surface age, overlay unit cost, patch unit cost, age adjustment factor, adjusted unit cost, and penalty fees. Field testing was done in accordance with the 1993 "AASHTO Guide of the Design of Pavement Structures." Testing sites were identified graphically with dimensions, and supported with digital pictures.
Los Angeles, California
"Street Damage Restoration Fee," prepared for Los Angeles by Dr. M. Y. Shahin, dated September 3, 1996, studied 100 sections in detail. Fifty sections were studied on local streets and fifty sections were studied on major streets. Visual inspections, deflection testing and penetrometer tests were conducted on each section. Performance curves were developed for the sections, with and without patching. Significant rehabilitation cost analyses were performed and ranged from $9.39/sf to $14.08/sf for major streets, and from $3.43/sf to $5.15/sf for local streets. A copy of Ordinance 171924 was attached to the report.
San Francisco, California
"The Effect of Utility Cuts on the Service Life of Pavements in San Francisco," Volume 1: Study Procedure and Findings, by Ghassan Tarakji, Ph.D., Final Report, dated May 1995 was prepared to determine if utility cuts shortened the life of asphalt pavement and if thicker overlays are required to compensate for the utility cut patches. The city's Pavement Management System database was used to screen out streets that could bias the aging process. The remaining streets were grouped into five classes based on pavement type and the traffic characteristics. The useful life of asphalt streets were grouped in three categories: less than 3 cutsâ€”26 years; between 3 and 9 cutsâ€”18 years; and more than 9 cutsâ€”13 years. The results show the pavement aging process is accelerated by increased levels of utility cuts. Results show reductions in service life ranging from 30 percent to 50 percent.
City of Chandler, Arizona
Completed in 2001, "Analysis for Pavement Cut Impacts," City of Chandler, Arizona, by ASU, is a report with strengths in the areas of fee schedule, photographs, cost analysis, field tests and specifications. It contains standard details relating to backfill, pavement and surface replacement that are specific in what is required for compaction. While these details do not originate with the City of Chandler, they have taken the most stringent standard details from some surrounding municipalities and governmental agencies and combined them into this document. The fee schedules shown are taken from two municipalities in the Phoenix Metro area as well as six others from other cities outside Arizona from Massachusetts to California. Another strength of this document is the conclusion and recommendation part. It has a formula for determining the costs/fees to be charged when disturbing the existing pavement.
League of Arizona Cities and Towns and Association of Public-Private Utility Service Providers Completed in 2002, "Evaluation of Pavement Cut Impacts," prepared for League of Arizona Cities by AMEC, dated January 7, 2002, is a compilation of studies completed by other investigators. No original investigations were completed in this study. This study is applicable to all Arizona conditions, including high-altitude, moisture available, freeze-thaw conditions. There is also a tabulation and review of existing pavement cut repair standards that have been adopted by Arizona municipalities or agencies, and development of an interim "best practice" repair standard. The conclusion and recommended interim standards and impacts section are detailed and thorough.
List of Submittals/Publications Evaluated in this Paper