Development and Testing of an AWWA Class IV Lining System: Steel Composite Lining System

The general requirements for structural classification systems are defined in AWWA Manual M28. Currently, there is no specific protocol or procedure for development and testing of AWWA Class IV lining system. The steel composite lining system (SCL) has been developed, tested, and installed for over the past 13 years. This paper will describe the liner design methodology, the materials, component, and full-scale model testing for the SCL system, which documents the AWWA Class IV classification. Rigorous testing with innovative technology at three levels transformed the SCL system from original concept to a Class IV lining system. The data collected during each level is used to better understand the design and construction methodology and their impacts on system performance. Full-scale mockup and testing along with posttest digital twin computational modeling verifies the design approach and Class IV lining system performance. As an additional proof of performance, an instrumented installation was monitored for more than one year, in situ. The long-term measurement further verified material and system performance while in water delivery service. Not all SCL tests were successful on the path to becoming a Class IV system. The SCL story is indicative of the need for testing on all levels to make sure the system in its final form can be designed using industry standards, is constructible as designed, and provides the functionality required.