TBSC 2018 Provisions on Design Shear Forces for Buildings with Rigid Basements

In this study, a representative reinforced concrete building structure incorporating laterally-rigid basement levels is first analyzed under design-level earthquake demands, by applying alternative linear elastic analysis methodologies recommended in the 2018 Turkish Building Seismic Code (TBSC 2018) for buildings with rigid basements. Subsequently, a nonlinear model of the structure is generated, and nonlinear response history analyses are conducted for the structure, under selected ground acceleration records that are scaled to represent design-level and maximum-considered ground motion levels. Nonlinear response history analysis results obtained for the seismic shear force demands developing along the stories of the building, as well as on individual structural wall cross-sections, are compared with design-basis linear elastic analysis results. Upon comparative evaluation of the analysis results, the reliability/conservatism of the alternative linear elastic analysis methodologies specified in TBSC 2018 for obtaining design-basis seismic shear force demands on buildings with rigid basements are discussed. The inconsistencies between the code-specified alternative analysis methods are identified, and potential improvements to code provisions are suggested.