Sliding Behaviour of Steel Liners on Surrounding Concrete in c-Cross-sections of Spiral Case Structures

Abstract

A hydropower house substructure, which is also called a spiral case structure (SCS), is usually made of steel-lined concrete. The research to date has tended to focus on the material non-linearity rather than the contact non-linearity in SCSs. The aim of this study is thus to examine the contact friction between the two components of a SCS, namely, the steel liner and the concrete. A structural finite element analysis (FEA) of a SCS was performed using commercial software. The available Coulomb friction model used to describe the contact nonlinearity has been validated based on the well-known push-off tests in 1985. The findings of this study suggest that, under internal water pressure (IWP), the steel liner will significantly slide towards the membrane’s extension range along the internal surface of the surrounding concrete in a c-cross-section of a SCS. Stronger friction leads to more IWP-resisting participation by the surrounding concrete. Based on this understanding, we argue that the friction coefficient should be recognized as an important design parameter. The exterior surface condition of steel spiral cases should be given a greater role in engineering practices of SCSs.