Rehabilitation of Existing 24, 30, and 36-Inch Waterline in High Traffic Areas

The City of Houston, the 4^th largest city in America, is facing the same dilemma as other metropolitan areas across the country - how to do more with less funding. A recent study performed on behalf of the City of Houston by Lockwood, Andrews, & Newnam, Inc. identified a priority of projects requiring replacement and rehabilitation. In the past several years, the City has been experiencing problems with existing 24, 30, and 36-inch cast iron water lines concentrated in the vicinity of the City's Museum District and the Galleria Mall retail and business area. These two areas experience very high traffic volumes and are considered some of the City's most recognized places. The 24, 30, and 36-inch water lines were constructed over 50 years ago and consist of cast iron material with caulked joints. Coupons cut from the existing line indicate the existing pipeline is structurally sound. However, the leak history of these lines indicates that a disproportionate amount of effort is required by City forces to maintain these lines, making them a maintenance burden for the City. Based on a preliminary analysis, it was determined most cost effective to rehabilitate the line was by installing interior joint seals. This paper will review the issues involved in the recommendation to rehabilitate the line. Additionally, it will present the challenges to take the existing line temporarily out of service during installation of the internal joint seals. Complicating the project design efforts, the project required extensive coordination with TxDOT and carefully planned traffic control measures. Special provisions were incorporated into the project to address concerns and minimize impacts to the local residents, retail facilities and businesses. Finally, the paper will summarize some of the lessons learned by undertaking a project with these types of constraints.