Title: Finite Element Analysis of UCSD Shear Columns

Author(s): R. K. Dowell and D. R. Parker

Publication: Symposium Paper

Volume: 205

Issue:

Appears on pages(s): 121-144

Keywords: ductility; nonlinear finite element analysis; reinforced concrete; seismic loading; shear capacity; shear columns; shear shedding; shear stiffness

DOI: 10.14359/11637

Date: 1/1/2002

Abstract:
Finite element analyses were conducted of as-built and seismically retrofitted RC bridge columns tested at UCSD. The as-built columns were provided with the same rectangular cross section and shear reinforcement, resulting in approximately the same shear capacity, but were designed to fail at different levels of ductility in either a brittle or flexural shear failure. This was accomplished by adjusting the shear force demand by varying the column height (or aspect ratio) and the grade of longitudinal reinforcement. In the analysis the challenge was to capture the overall force-deformation hysteretic behavior and failure mechanism, as well as the individual deformation components of flexure and shear. The analysis focuses on the shear behavior of concrete under large tensile strains and calibrates the shear stress capacity to the concrete component of the UCSD shear model, which reduces as a function of curvature ductility at the critical section. Also, the shear modulus is reduced in proportion to the ratio of cracked to gross flexural stiffness. The results show that a relatively simple design oriented shear capacity model can be used to calibrate the required shear parameters of the 3-D plasticity concrete model. In the paper, detailed finite element analyses are conducted to assess the shear force capacity and post-peak deformation response of shear dominated RC bridge columns.