Time-Variant Performance of Concrete Sewer Pipes Undergoing Biogenic Sulfuric Acid Degradation

Abstract

The paper presents a methodology for the advanced design of buried concrete pipes or assessment of their performance that enables realistic decisions to be taken concerning the safe and cost-effective operation of sewage pipe systems during their service life. In this respect, the influence of microbiologically induced corrosion (MIC) on bearing capacity is modeled as a time-dependant and stochastic problem. The potential of the approach is shown by performing parametric studies concerning the crushing strength of both uncorroded and corroded pipes and by comparing these results with results from tests. Also, a complex analysis of a concrete buried pipe is presented via combined use of finite-element software for concrete structures, its randomization, and degradation phenomena modeling. Using statistical processing, the reliability level can be assessed based on a relevant limit state, and a service-life prognosis can be made. This is in contrast to current methods developed worldwide for the design or assessment of buried concrete sewage pipes based in practice on simplified models; thus, reliability level and service-life issues are not treated.