Natural frequency of structure is a representation of the flexibility of structure which is a function of stiffness
and mass. Natural frequency can be increase by increasing the stiffness or reducing the mass. In this study, the
evaluation of natural frequency used three type of reinforced concrete frame structure that is special moment resisting
frame, dual system special moment resisting frame combine with core wall and dual system special moment resisting
frame combine with frame wall (wall integrated into moment resisting frame). Based on SNI 1726-2012, the 15th story
of appartment fictive building is located at 7046”24’ SL and 110027”7’ EL are classified as Seismic Used Group II ,
assign an Occupancy Importance Factor (I) of 1.0 and Seismic Design Category D. The response modification
coeefficients for special moment resisting frame R = 8.0 and for dual system R = 7, the system overstrength factor for
special moment resisting frame 0=3 and for dual system 0=2.5, and the deflection amplification factor Cd = 5.5 for
all type of structure. The Structural Analysis Program (SAP 2000) used to evaluated natural frequency, displacement,
drift story, axial force and moment of column. Result of this study proved that using shear wall as core wall or frame
wall increased the natural frequency and stiffness of structure. The placement of shear wall with the same mass as core
wall and frame wall give significant influence on natural frequency. The most effective type of structure to increase
natural frequency is dual system special moment resisting frame combine with frame wall because wall surface area is
larger than core wall.
Keyword :
Natural Frequency,
Moment Resisting Frame,
Core Wall,
Frame Wall,
Story Drift,
