Calibrated analytical element for lateral-strength degradation of reinforced concrete columns

An analytical element is proposed to simulate the cyclic nonlinear lateral-strength behavior of reinforced concrete columns. The element possesses a unique and novel combination of functionalities that allow increased accuracy of simulation as well as ease of use. Key functionalities are: (1) the ability to simulate cyclic as well as in-cycle strength degradation including hysteretic pinching and damage accumulation, (2) the ability to monitor column boundary condition and adjust behavior accordingly, (3) full calibration to a dataset of column tests allowing users to only define column material and geometric properties for the element to automatically determine all cyclic behavior parameters. Parameters of the material model governing the element were related through regression analyses to predictor variables to arrive at governing relations for the parameters. In the process of calibrating model parameters, correlations were uncovered that provide insight into mechanisms that affect column cyclic lateral-strength. The proposed element and material model were calibrated to simulate the seismic behavior of lightly confined reinforced concrete columns that experience flexural yielding prior to sustaining lateral-strength degradation through a shear failure mechanism. Calibration to other column types is the subject of future work.