Improved geometric design of earthquake-resistant RC slender structural walls. I: Parametric study

In multistoried RC wall-frame buildings, properly designed and detailed RC slender structural walls significantly improve earthquake resistance. In walls on isolated spread footings with marginal taper, severe stress concentration is observed at the wall-footing junction during earthquake shaking. In this paper, new tapered configurations are proposed in the bottom portion of walls with and without enlarged boundary elements. Analytical correlations are derived among salient structural and soil parameters of the tapered wall-footing. An extensive parametric study is carried out through linear-elastic finite-element analysis of an isolated wall-footing system under estimated actual vertical and lateral forces. Under the estimated forces, significant loss of contact is observed at the bottom of the wall-footing; thus, soil or rock anchors need to be provided to ensure stability of the wall-footings during strong shaking. Force flow from wall to footing improves significantly in the proposed integrated wall-footing system. In the wall, the region of the inelastic response and possible seismic damage is expected to occur above the tapered region and away from the footing level. Permissible parametric limits are also proposed through the observed stress-deformationresponse. © 2014 American Society of Civil Engineers.