دلیل حذف دیوارهای برشی در طبقات بالاتر
Overall lateral deformations of HFs are primarily generated by shear racking (frame) and fl exural bending (bracing system or wall). Frame lateral displacements reduce as the height increases; conversely,lateral defl ections of braced frames and structural walls increase with the height. The net effect is that at lower storeys, bracing systems and walls are stiffer than frames, while, in turn, the latter possess higher stiffness at upper fl oors. This difference in lateral stiffness along the height between the structural components of HFs signifi cantly affects the distribution of seismic actions as shown, for example, in Figure A.17 . The shear resisted by the frame in HFs increases with the height, vice versa for the interacting wall. It is also observed that the total shear carried by the MRF at top storeys can exceed the applied seismic action (also referred to as ‘ negative storey shear share ’ ). Effects of negative storey.
