Modelling the Shear Behavior of Short Columns under Single Curvature

Abstract

Short concrete columns are the structural members dominated with nonlinear strains distribution (D region), and they are characterized with small shear span to depth ratios. Since short columns fail in brittle shear pattern, they can not be modelled using the plane -sections-remain-plane hypothesis (beam theory). Therefore, this thesis introduces an effective and simple approach to model such members by applying the modified 3PKT theory which is originally based on a three-degree-of-freedom kinematic model for the deformation patterns in walls. This research also focuses on verifying the ability of non-linear finite element software (VecTor2) to capture the responses behaviour of short columns and compare the FEA results with both experimental and 3PKT results. Several experimental studies on short reinforcement concrete columns have been filtered to only three series of experimental studies to be placed as a test database which is applicable for the scope of the project. The series specimens are having either rectangular or square sections and their experimental test setup is a single beam configuration with aspect ratios smaller than approximately 3.0. Then, the specimens have been modeled using the two tools (3PKT-VecTor2). The results showed that both approaches successfully predicted the shear behavior of the specimens. The resulted peak load experimental to predicted ratios of VecTor2 and 3PKT approaches have a mean value of 0.87 and 0.98 with a coefficient of variation of 7.58% and 6.78 % respectively.

Short concrete columns are the structural members dominated with nonlinear strains distribution (D region), and they are characterized with small shear span to depth ratios. Since short columns fail in brittle shear pattern, they can not be modelled using the plane -sections-remain-plane hypothesis (beam theory). Therefore, this thesis introduces an effective and simple approach to model such members by applying the modified 3PKT theory which is originally based on a three-degree-of-freedom kinematic model for the deformation patterns in walls. This research also focuses on verifying the ability of non-linear finite element software (VecTor2) to capture the responses behaviour of short columns and compare the FEA results with both experimental and 3PKT results. Several experimental studies on short reinforcement concrete columns have been filtered to only three series of experimental studies to be placed as a test database which is applicable for the scope of the project. The series specimens are having either rectangular or square sections and their experimental test setup is a single beam configuration with aspect ratios smaller than approximately 3.0. Then, the specimens have been modeled using the two tools (3PKT-VecTor2). The results showed that both approaches successfully predicted the shear behavior of the specimens. The resulted peak load experimental to predicted ratios of VecTor2 and 3PKT approaches have a mean value of 0.87 and 0.98 with a coefficient of variation of 7.58% and 6.78 % respectively.