Inelastic deformation behaviour of RC bridge piers
Author: Duc Thong Tran
Language: English
Abstract
The framework of this thesis are the papers, Inelastic Deformation Analysis of Reinforced Concrete Bridge Piers, Part 1 & 2, published in the ACI Structural Journal from Bimschas et al.. The papers present a concept to describe the flexural behaviour of RC members throughout all load stages. It is proposed to take tension shift into account by means of discontinuous stress fields. This work consists of two parts: 1) further experimental validation of the concept; 2) application of the concept within the context of plastic hinge models.
Part 1: Two static-cycling experiments performed at ETH Zurich are used to validate the concept. It is shown that the global response can be predicted accurately until concrete peak strength is reached, whereas for the general case, the post-peak behaviour can not be predicted yet. It is also shown that the corresponding strains in tension and curvature χ can be predicted accurately, while the compression chord behaviour can not be captured in the base region. Main reason for both is that the analysis can not consider global softening behaviour forcing the use of a modified concrete law with post-peak plateau.
Part 2: An approach is presented which only focuses on the tension chord behaviour, assuming that for low normal force levels, deformation results mainly from elongation of the longitudinal reinforcement. Thereafter, a plastic hinge model is presented, and the corresponding plastic hinge length Lp is derived for a one rebar layer model. The parameter study shows that Lp is sensitive to the normal force level and the aspect ratio and insensitive to the longitudinal and transversal reinforcement ratio.
