Guidelines for inspecting, maintaining and rehabilitating highway and rail transit tunnels from coast to coast are now available in two new manuals and a computer software program jointly produced by the Federal Highway Administration (FHWA) and the Federal Transit Administration (FTA). The Highway and Rail Transit Tunnel Inspection Manual and Highway and Rail Transit Tunnel Maintenance and Rehabilitation Manual, along with a software program to collect data on tunnel components, present the first nationwide tunnel management system. FHWA and FTA developed the manuals with the common goal of providing uniformity and consistency in assessing the physical condition of various tunnel components. With numerous tunnels in the U.S. now more than 50 years old and beginning to show signs of considerable deterioriation, particularly due to water infiltration, such assessments are vital. Also outlined are best practices for maintenance and rehabilitation, which are designed to extend the service life and reduce operating expenses of tunnels.
The inspection manual defines major tunnel components and systems and then describes the fundamentals of tunnel inspection, including sections on preparing for an inspection, recording inspection results and recommended safety practices. Suggested standard forms are included that can be used to record the actual structural condition codes noted during the inspection. Inspection procedures are outlined for structural elements, mechanical systems, electrical systems and other systems/appurtenances, including specific defects to look for during the inspection. Also included are recommended procedures to follow in the event that the inspection reveals defects that require immediate repair. The final chapter offers suggestions on how to properly record the results of an in-depth inspection. Repair priority definitions are presented so that the individuals writing the inspection report can classify the defects based on definitions for critical, priority and routine classifications.
The maintenance and rehabilitation manual provides specific recommendations for performing preventive maintenance on the tunnel structure, mechanical systems, electrical elements, track systems and miscellaneous appurtenances. Also presented are recommendations for making structural repairs to various types of tunnel liner materials, including how to slow, stop or adequately divert water infiltration.
A detailed section also addresses the various structural repairs that can be made to concrete, such as repairing cracks and spalls. The manual’s appendix includes a general discussion of life-cycle cost methodology.
The TMS software program is designed to allow highway and transit tunnel owners to monitor the physical condition of their tunnel features. If used over a period of time, the software will provide a tool for the owners to see trends in the performance of particular components of their systems.
The software provides owners with online access to data that documents component conditions. This data is in the form of condition ratings, sketches and photographs of defects, inspector comments, repair logs and costs associated with repairs. The user interface allows access to the data through a graphical click-and-point method.
Electronic copies of both manuals are now available on the Transportation Asset Management Today Community of Practice website (assetmanagement.transportation.org).
The computer software program will be posted on the site early this summer. The site is sponsored by the American Association of State Highway & Transportation Officials, with support from FHWA and the Transportation Research Board. To download the manuals, click on ?Tunnel Management? and then ?Reference.? The tunnel management section of the website also features articles and other reference documents, a discussion area, announcements of upcoming events and a directory section. The directory lists names and contact information for those who have joined the Community of Practice.
The new state-of-the-art tunnel management technology is an important tool that all highway and transit agencies can use to better assess and maintain their tunnel systems. The ultimate benefits are a longer, safer and more cost-effective service life for this critical link in our transportation system.