Select the seismic zone in which your vessel is operating. The seismic zones are pictured in ASCE #7 and reproduced in the accompanying illustration. A value of 0 will not increase the saddle reaction force. An Identifier of 5 (Zone 4) will produce the highest saddle load reactions. These values are derived from UBC. The basic equation for lateral G force is :
Cs = Z I C / Rw : Rw = 3, C = 2.75, I = 1.0
|
Seismic Zone |
Cs |
|---|---|
|
0 |
0.0 |
|
1 |
0.069 |
|
2a |
0.138 |
|
2b |
0.184 |
|
3 |
0.275 |
|
4 |
0.367 |
The following illustration shows a seismic risk map of the United States from the ASCE code:
