RC wall shear-flexure interaction: Analytical and experimental responses

Analytical and experimental investigations were conducted to develop a modeling approach that integrates flexure and shear interaction to obtain a reliable prediction of the inelastic response of reinforced concrete walls. The model incorporates RC panel behavior described by a rotating-angle model into the fiber-based Multiple Vertical Line Element Model (MVLEM). Model responses were compared with experimentally obtained responses for panels under pure shear, as well as for slender and short walls. The model produces good correlation with panels under pure shear and for slender walls, where the model was able to predict the nonlinear shear responses reasonably well. For short walls, accurate predictions of overall load-displacement response were obtained for walls with relative higher shear span ratio (1.0 to 0.69). Discrepancies were observed in shorter walls due to the assumption of zero-horizontal-stress, because the constraining effect from wall ends reduces the horizontal strains and increases the shear strength compared to the zero-horizontal-stress assumption. Data collected in an experimental program carried out as part of this study were used to improve model response predictions by modifying some of the model assumptions.; The experimental program consisted of four spandrels and six piers that were three-quarter scale replicas of typical wall segments in older California buildings (∼1960). The experimental program was designed to provide information on the degradation of lateral load at large deformations and collapse in the case of piers with axial load. Detailed instrumentation was provided on the test specimens to measure average horizontal strain, distribution of horizontal strain, and distribution of shear strain to study the sensitivity of the predicted model responses to various assumptions. Detailed calibration of the model was conducted by comparing the analytically predicted and experimentally observed behavior of short RC walls. Model accuracy was improved by using an average horizontal strain, whereas other parameter variations, such as distribution of shear or horizontal strain, had less impact.