What Does Liner Flexural Strength Mean?
Liner flexural strength is the strength of a liner in terms of bending expressed as the tensile stress of the outermost fibers at the instant of failure. Flexural strength of a cured-in-place (CIPP) liner can be expressed as the load that the liner can withstand without failing. A three point bending test, similar to the modulus of elasticity, is used to determine the flexural strength of a liner. In trenchless technology, the use of CIPP liners is one of the most cost effective and efficient methods of sewer rehabilitation.
Also known as modulus of rupture, bend strength or transverse rupture strength.
Trenchlesspedia Explains Liner Flexural Strength
Before a liner is designed, a complete analysis of existing site conditions such as pipe depth, existing pipe condition, surface loading on the pipe and soil conditions. The CIPP long term creep behavior depends on the long term flexural strength of the liner. The flexural test results are used to determine the long term behavior a liner will exhibit. The test known as the three point test consists of placing, flatwise, a specimen of CIPP liner on two rigid supports and loading it at mid point until the specimen fails or reaches a strain of 5% on its outer fibers. The results are noted to analyze the behavior of the material. This test is important because it determines the strength of the material to be used for lining damaged pipes depending on the existing conditions of forces that the pipe will be subjected to from the surrounding soil, surface load and ground water.