Analysis and Design of RPM and Other Composite Underground Pipelines

Abstract

Glass‐fiber‐reinforced plastic mortal' pipes had been in use for pressure and nonpressure underground applications since 1965. Although this material had been used on many projects, the loads imposed on these piplines had not been well understood by most design engineers and manufacturers. In addition, the individual laminate behavior of the composite pipe wall was never modeled in any of the calculations performed by the manufacturers. Also, the effects of soil‐pipe interaction were never properly addressed in the design procedures used. These practices had led to numerous premature failures of reinforced plastic mortar (RPM) pipelines in the United States and other countries and as a consequence, this product disappeared from the market in 1984. In an attempt to inform the design engineers who might be considering similar underground pipeline projects, the loadings applied on these pipelines are reviewed in this paper. A new design procedure was developed based on a composite pipe‐soil interaction finite element model. Some details of this microcomputer‐based design tool are introduced in this paper. The applicability of the new analysis and design procedure in RPM and other composite pipe design is demonstrated by a typical design application.