Software Verification PROGRAM NAME: REVISION NO.:
SAP2000 0
EXAMPLE 1-020 FRAME - RESPONSE SPECTRUM ANALYSIS OF A TWO-DIMENSIONAL RIGID FRAME EXAMPLE DESCRIPTION A single-bay, two-story, two-dimensional, reinforced concrete frame is analyzed in this example. The applied loading is a response spectrum using 5% modal damping. The SRSS modal combination technique is used. The building periods, lateral displacements and bending moments in the columns and beams are compared with the independent results presented in Chopra 1995. Important Note: The analysis in Chopra uses logarithmic linear interpolation, whereas SAP2000 uses algebraic linear interpolation. Consequently, in the SAP2000 model the values of ground acceleration corresponding to the time periods of the structure are explicitly provided. Important Note: Only bending deformations are considered in the analysis. Shear and axial deformations are ignored. In SAP2000 this is achieved by setting the property modification factor for area to 100,000 and setting the property modification factor for shear area to 0. Important Note: Only the Ux, Uz and Ry degrees of freedom are active in the SAP2000 model. The building mass is only active in the X-direction; that is, vertical excitation and out-of-plane excitation of the mass are not considered. GEOMETRY, PROPERTIES AND LOADING
2EI
1
6 4
2EI 5 2m 7
2EI 6
Z
5 3
Y
1
X
240"
EI
m8
2
2 120"
EI 8
4
2EI
EI
120"
3
EI 7
Properties E =3,000 k/in2 I = 1,000 in4 Concentrated Masses 2m at joint 7 m at joint 8 m = 0.5182 kip-sec2/in
5% Damped Response Spectrum Function Period (sec) 0 0.03 0.125 0.5868 0.66 1.562 4.12 10
Accel (g) 0.5 0.5 1.355 1.355 1.355 0.576 0.218 0.037
Fixed Base Frame
EXAMPLE 1-020 - 1