Buckling experiments on polyethylene liners with egg-shaped cross-sections

摘要

ABSTRACT: In Germany, egg-shaped concrete and masonry sewers can be renovated with shortnthermoplastic liners of corresponding cross-sections. The decisive variable for dimensioning of thenwall thickness is the groundwater pressure on the liner surface. The necessary calculations are, asna rule, executed by data processing procedures. Buckling experiments are important for thendevelopment of the theoretical approaches. The specific material behaviour of thermoplastics, andnin particular their creep tendency, is considered in the experimental planning. In total, the resultsnof 11 buckling experiments with different imperfections (none, annular gap or local imperfection)nconcurred with the buckling pressures determined by calculation. Ten small-scale experiments andnone full-scale test were carried out at constant external pressure as creep tests of over 2–3 h innduration. The evaluation of the 11 experiments shows that the application of the German designncode ATV-M 127-2 for the calculation of the stability of egg-shaped profiles subjected to waternpressure (host pipe states I and II) is suitable. The small-scale experiments showed that lessnextensive set-ups still supply useful information when examining the load-carrying capacity of non-ncircular liners. Such experiments could be carried out within the framework of first examinationsnand for quality assurance.