Structural Analysis Modeling of Unbonded Prestressing in Prestressed Concrete Containments

摘要

Containment structural analysts need to develop models that represent the geometry, structural details and material properties which are 'important' to the response regime being analyzed and to the goals of the analysis. With continuing advances in computational tools, the trend has been to model containments with more elements, more detail, and more comprehensiveness than ever before. The focus of this paper is on the evolution and lessons learned related to modeling of unbonded prestressing tendons (or their effects) in prestressed concrete containments.This paper presents an overview of the modeling options used by the authors or by others during many years of containment integrity research at Sandia National Laboratories. The paper then discusses the strengths, limitations, and challenges of various modeling methods, and priori tizes the levels of modeling sophistication in context with the goals of the analysis, and uncertainties of existing input and validation data A number of scale model tests and analytical efforts are cited to show trends within the industry and lessons learned.The paper also presents results of finite element analyses of a "ring model" (slice through a typical containment cylinder), comparing different prestress tendon modeling strategies. These range from simulation as embedded rebar with and without stress variation due to friction, to discrete tendon models with explicit representation of friction using contact surfaces.