CONTRIBUTIONS OF COLUMN, BEAMS, AND SLABS STIFFNESS ON SEISMIC PERFORMANCE OF HIGH RISE BUILDINGS

The stiffness of columns, beams, and slabs were reduced by 10% to 90% to show by what value each element can be contributed the overall performance of the high rise buildings under seismic load. A 13th models were analyzed using SAP2000 version14 for square and rectangular in plane 12th floors RC buildings to illustrate the contribution of column stiffness and cross section (rectangular or square), building plane, beams stiffness and slab stiffness on resistance the earthquake (El-Centro). The studied variables which show how the variation in the stiffness contribution which a comparable response is investigated are top displacement, top acceleration, base shear force, base bending moments and base normal force. The study shows that the stiffness of columns contribute by nearly 55%, beams by nearly 20% and slabs by nearly 10% of earthquake resistance of high rise buildings. Rectangular columns orientations contribute by nearly 40% of building earthquake resistance. Rectangular cross section columns must be oriented by the way that achieves the maximum resistance the earthquake loads. In buildings with slander, exterior column orientations can be enhanced the stiffness of the short direction to control the top displacements and accelerations values in both x and y directions.