Seismic Retrofitting of Pilotis RC Buildings Using Steel Buckling-Restrained Braces: Influence of Brace Inclination Angle on Performance

This study investigates the influence of buckling-restrained brace (BRB) inclination on both seismic response and usable architectural space in old pilotis-type RC buildings. Four RC frames (2, 4, 6 and 8 storeys) were retrofitted using six BRB layouts: either two diagonal braces at the exterior bays or a single central brace, each inclined at 40°, 50°, or 60° to the horizontal. Nonlinear time-history analyses with 21 far-field ground motions evaluated interstorey drift, residual displacement and base shear. Based on these findings, empirical formulas are proposed for the preliminary design of BRB retrofits in pilotis-type RC buildings.