G.17.4.1.8 Lateral Load Distribution
Lateral loads can be applied by any one of the following three methods per Section 3.3.3.2.3 of FEMA 356.
Method 1
The vertical distribution of the base shear shall be as specified in this section for all buildings. The lateral load applied at any floor level x shall be determined in accordance with equation (1-8-1) and equation (1-8-2):
| Fx = CvxV | (1-8-1) |
| = |
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Method 2
A vertical distribution proportional to the shape of the fundamental mode in the direction under consideration is performed. Use of this distribution shall be permitted only when more than 75% of the total mass participates in the fundamental mode in the direction under consideration, and the uniform distribution is also used.
| (1-8-3) |
Method 3
A vertical distribution is performed consisting of lateral forces at each level proportional to the total mass at each level .
| (1-8-4) |
| = | ||
| = | = 2.0 for T ≥ 2.5 seconds = 1.0 for T ≤ 0.5 seconds | |
| = | ||
| = | ||
| = | ||
| = | ||
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