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Highway & Rail Transit Tunnel Maintenance & Rehabilitation Manual
Table Of Contents
List Of Tables
List Of Figures
In March of 2001, the Federal Transit Administration (FTA) engaged Gannett Fleming, Inc., to develop the first ever Tunnel Management System to benefit both highway and rail transit tunnel owners throughout the United States and Puerto Rico. Specifically, these federal agencies, acting as ONE DOT, set a common goal to provide uniformity and consistency in assessing the physical condition of the various tunnel components. It is commonly understood that numerous tunnels in the United States are more than 50 years old and are beginning to show signs of considerable deterioration, especially due to water infiltration. In addition, it is desired that good maintenance and rehabilitation practices be presented that would aid tunnel owners in the repair of identified deficiencies. To accomplish these ONE DOT goals, Gannett Fleming, Inc., was tasked to produce an Inspection Manual, a Maintenance and Rehabilitation Manual, and a computerized database wherein all inventory, inspection, and repair data could be collected and stored for historical purposes.
This manual provides specific information for the maintenance and rehabilitation of both highway and rail transit tunnels. Although several components are similar in both types of tunnels, a few elements are specific to either highway or rail transits tunnels, and are defined accordingly. The following paragraphs explain the specific subjects covered along with procedural recommendations that are contained in this manual.
This chapter presents a brief history of the project development and outlines the scope and contents of the Maintenance and Rehabilitation Manual.
Tunnel Construction and Systems
To develop uniformity concerning certain tunnel components and systems, this chapter was developed to define those major systems and describe how they relate to both highway and rail transit tunnels. This chapter is broken down into four sub-chapters that include: tunnel types, ventilation systems, lighting systems, and other systems/appurtenances.
The tunnel types section covers the different tunnel shapes in existence, liner types that have been used, the two main invert types, the various construction methods utilized to construct a tunnel, and the multiple different finishes that can be applied, mainly in highway tunnels. The ventilation and lighting system sections are self explanatory in that they cover the basic system types and configurations. The other systems/appurtenances section is used to explain tunnel systems that are present in rail transit tunnels, such as: track systems, power systems (third rail/catenary), and signal/communications systems.
This chapter provides specific recommendations for performing preventive maintenance to the tunnel structure, mechanical systems, electrical elements, track systems, and miscellaneous appurtenances. The tunnel structure recommendations deal with tunnel washing, drain flushing, ice/snow removal and tile removal. The procedures for the mechanical and electrical systems/elements are given in tabular format and include a suggested frequency for each of the tasks listed. Track systems are divided into track and supporting structure, power (third rail/catenary), and signal/communication systems. The last section for miscellaneous appurtenances covers the following three categories: 1) corrosion protection systems, 2) safety walks, rails, and exit stair/ladder structures, and 3) vent structures and emergency egress shafts.
Rehabilitation of Structural Elements
The last chapter of this manual offers general procedural recommendations for making structural repairs to various types of tunnel liner materials. A large section is devoted to covering repairs necessary to slow, stop, or adequately divert water infiltration. Following that section is a detailed section that addresses the various structural repairs that can be made to concrete, such as repairing cracks and spalls. The last section deals with each of the following liner types: cast-in-place concrete, pre-cast concrete, steel, cast iron, shotcrete, masonry, and exposed rock.
Life-Cycle Cost Methodology
Appendix A of this manual includes a general discussion of life-cycle cost methodology. This process could be used when determining which method of repair is most cost effective over the long term. Also, it could be used to determine if it is more beneficial to purchase a new piece of equipment or to continue maintaining the existing piece.
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