Page 53 - Vol.06

Building Column Spacing Beam Size Girder Size Slab
A Steel/RC 21’4” × 32’0”@85.3” c/c W27 × 84 W30 × 116 3.5” nwt concrete on 2” metal decking
(fully fitted out)
B Steel/RC 21’0” × 28’1” W21 × 44/W21 × 73 @84” c/c W24 × 76/W24 × 84 3.25” lwt concrete on 3” metal decking
(core & shell)
C RC
(fully fitted out) 21’0” × 27’0” 12”W × 14”D @42” c/c 30”W × 24”D 5” nwt concrete
D Steel/RC 28’6” × 28’6” W16 × 31 @9.5’ oc 21”W × 73”D 3.25” lwt concrete on 2” metal deck
(ductwork & partitions)
Table 6. Floor geometry and Construction

are calculated. 30000

2. Calculate 25000
SCI P076
20000
3. The peak velocity vn in each mode n AISC
at point i on the floor due to walking rms velocity, min/s 15000 BBN
at point j is calculated 10000 Arup

using where Measured
are the mode 5000
shape deflections at point i and j; 0
A B C D
and is the mode mass Floor
Figure13. Comparison of predicted vibration levels
4. The total vibration response to each
800
footfall is found by summing the
velocity responses in each mode in
the time domain. 400
• Validation and comparison with
measurements m/s 0
There’re four different Building floors
for comparison, Buildings A–C are -400
laboratories with ‘high-frequency’ floors
Walker
and Building D is a hospital with a ‘low- ambient
-800
frequency’ floor; key structural details 0 10 20 30 40 50
Time, Seconds
are given in Table 6; and the vibration Figure14. Walker-induced and ambient vibration of office building
levels in micro-inches/s for the four floors
800
are compared to the measurements in
Figure 13. The results show Arup has best
accuracy. 400

Discussion and Further
Analysis m/s 0
The walker-induced vibration of
three different floor structures is shown -400
from Figure 14 to Figure 15. Figure 14 Walker
is 9.6m*9.6m steel structure for office, ambient
-800
Figure 15 is 4.8m*4.8m RC structure, 0 10 20 30 40 50
Time, Seconds
designed as VC-B (1,000 in/s) and Figure Figure15. Walker-induced and ambient vibration of 4.8m*4.8m span floor

NEW FAB TECHNOLOGY JOURNAL APRIL 2012 53