F-06 (2D Steel Frame Vibration) |
  
|
F-06 (2D Steel Frame Vibration) |
|
Objective
To verify the behavior of the beam element in large 2D steel frame vibration
Problem Description
A 5-span, 12-story 2D steel frame vibrates under its own weight as shown below. All beams are W24’s and all columns are W14’s
Material properties: E = 29000 ksi, ν = 0.3, density = 483.84 lb/ft3
Interior columns: Exterior columns:
Floor 1 – 4: W14x120 Floor 1 – 4: W14x90
Floor 5 – 8: W14x90 Floor 5 – 8: W14x68
Floor 9 – 12: W14x68 Floor 9 – 12: W14x48
Beams:
Floor 1 – 4: W24x131
Floor 5 – 8: W24x104
Floor 9 – 12: W24x84
Units: Iz, Iy and J – in4, A, Ay and Az – in2
Section |
Iz |
Iy |
J |
A |
Ay |
Az |
W14X120 |
1380 |
495 |
9.37 |
35.3 |
8.555 |
23.03 |
W14X90 |
999 |
362 |
4.06 |
26.5 |
6.16 |
17.1583 |
W14X68 |
722 |
121 |
3.01 |
20 |
5.81 |
12 |
W14X48 |
484 |
51.4 |
1.45 |
14.1 |
4.692 |
7.96308 |
W24X131 |
4020 |
340 |
9.5 |
38.5 |
14.8225 |
20.64 |
W24X104 |
3100 |
259 |
4.72 |
30.6 |
12.05 |
16 |
W24X84 |
2370 |
94.4 |
3.7 |
24.7 |
11.327 |
11.5757 |
Finite Element Model
132 beam elements
Model type: 2D Frame (shear deformation included)
Results
The first three natural frequencies are compared with another program, Frame Analysis & Design (STRAAD) [Ref. 1].
Units: Hz
|
ENERCALC 3D |
Frame Analysis & Design (STRAAD) |
Mode 1 |
1.7508 |
1.7402386 |
Mode 2 |
4.6904 |
4.6629050 |
Mode 3 |
7.9692 |
7.9228372 |
Comments
The results given by ENERCALC 3D are very close to the referenced values.
Reference
[1]. “Frame Analysis & Design”, Digital Canal Corporation, Dubuque, Iowa, USA
