The objectives of this project are: to quantify the stress-transfer process in concrete columns due to creep deformations, (2) to determine if column longitudinal reinforcement can yield under the action of sustained axial loads, (3) to identify changes in column lateral strength, stiffness, and deformability, and (4) to define the influence of axial load, sustained axial loads, (3) to identify changes in column lateral strength, stiffness, and deformability, and (4) to define the influence of axial load, sustained load period, and material properties on column response to lateral loads. Laboratory specimens, comprising pairs of beam-column subassemblages will be subjected to a sustained axial load prior to the lateral load tests. A computerized nonlinear model will be developed to simulate the behavior of the columns including realistic representation of material properties, effect of transverse reinforcement, and creep effects. This is a research initiation award to develop a computational method for assessing the effect of sustained loads on the integrity of concrete columns. Use of the model will allow the user to define the strength, stiffness, and deformation limits of old concrete columns.
