Technical Information
Structural Testing
Tests in the Large Soil Cell Laboratory a Utah State University (USU, 1993) showed that a 27” ID Liner with grout of compressive strength of 8.600 psf improved the zero deflection load capacity of a fully deteriorated (broken by 4 longitudinal cracks) of 30” unreinforced concrete pipe by over 3,000 psf (4,600 psf vs. 1,500 psf).
Effects of Danby Liner
Increase in Strength at d =0, P' = 3100 psf
Increase in Stiffness – Ration of Slopes = m'/m = 1.4
Load Deflection Data for Lined and Unlined Pipes
In a more standard test for rigid pipes, the Danby Liner was subjected to D-Load (three edge bearing) testing supervised by the County Sanitation Districts of Los Angeles County (Rialto, 1993). These tests were conducted on old 24” RCP which had been salvaged when it was replaced. The upper half (approximately) of the pipe circumference was corroded away by 1.25” – 1.50” of the original 3” wall thickness. One 4 foot section was lined with a 21” liner covering the full (360º) circumference. A second 4 foot section was lined over 270º (90º at the invert was not lined) resulting in a vertical diameter of 23” and a horizontal diameter of 22”. The D-Load strength of the full (360º) Danby lined pipe was 2.17 times that of the unlined mating 4 foot section which was cut from the same original 8 foot pipe. The partial (270º) liner was 1.93 times as strong as its unlined mate.