The Adverse Effects of Perimeter Frame Discontinuity on Earthquake Response of RC Buildings

Being one of the most traditional characteristics of Turkish building stock, overhang is a structural feature which adversely affects the earthquake response of reinforced concrete buildings by changing the mass distribution, plan regularity and column bending moments. Since this outward offset concerns only the perimeter beams and not the perimeter columns, a slab section between the latter remains without beams, leading thus, partly or completely, to perimeter frames that consist of slab bands instead of beams. In this paper, the application of overhang, which is frequently repeated and allowed by recent codes, has been investigated. 12 case study buildings designed according to the current and the former Turkish Earthquake Codes are analyzed with linear and nonlinear analysis tools in order to capture the real contribution of the aforementioned weakened perimeter frames and the overall earthquake response. Finally, code requirements have been investigated and design aspects have been suggested to the structural designers.