Structural sensitivity of circular sewer liners to geometrical imperfections

The impact of geometrical defects of liners on their structural performance has been examined in this article. The major common imperfections, such as gap, ovality and wavy imperfections, have been taken into consideration. In the first step, the influence of separate imperfections is presented. Then, the combination of coinciding defects is examined. The formula for weighted influence of individual defects has been found, based on a wide range of FEM calculations and statistical interpretation. All the examinations performed led to improving the general formula for critical groundwater pressure.