Onshore Panel Webinar: Recent advances in CIPP and sprayed liner design
Firstly, he will describe design methods for sprayed cementitious liners when used for corrugated steel culverts, and reinforced concrete culverts and sewers. Methods are outlined for calculating moment resistance of the rehabilitated pipes, considering either bonded or unbonded interaction of the sprayed liner and the host pipe, as well as the condition of the host pipe (e.g. intact reinforced concrete pipes with leaking joints, or pipes that have cracked under service loads, or where concrete cover has been lost over the tension steel, or where the tension steel has corroded).
Rigid pipelines rehabilitated with cured in place pipe (CIPP) liners can be subjected to differential ground movements from causes such as earthworks (e.g. tunneling), slope movements, and climate change. The liner will then be subjected to longitudinal stress and strain at locations where it spans across bell and spigot joints, or new ring fractures that develop in the host pipes. Closed form and finite element solutions have been developed to provide estimates of the stress and strain in the liners – so that the potential impact of the ground deformations can be estimated. The solutions can also be used to select suitable thickness and material properties for a liner where it is to be installed to protect an existing water or sewer pipe that is expected to be subjected to temporary or permanent ground deformations.
References will be provided where details of the analyses and design methods have recently been published.
