Numerical and analytical investigation of load transfer through eccentric columns with different cross sections

Abstract

Eccentric columns are not a common feature in concrete building structures. However, late changes in floor layouts and constraints due to available spaces may enforce structural designers to use eccentric columns to transfer vertical load. The load paths of the eccentric column connections can create complications. Due to the sudden changes in geometry, additional stresses are developed at the slab- column connection and a discontinuity region is created in which the strain distribution becomes highly nonlinear and unpredictable. The strut and tie method has been extensively used in analysing such complicated structural elements over the years. This method has its own limitations and is based on simplifications including the definition of the load path. This simplified method can under or over predict the design capacities of such columns, which can be inefficient or inadequate for current design requirements. The objective of this study is to comprehensively investigate the load transfer mechanism for vertical loads of eccentric columns using an advanced finite element approach. Clear identification of the load path, effective cross-sectional area for load transfer and alternative design guidelines for column-slab joint are evaluated and the preliminary work is presented in this paper.