Seismic Base Shear Examples
- Ömer Can Sagbas (Unlicensed)
Calculation the seismic base shear of a 12-story reinforced concrete office building illustrated in Figure 1 and Figure 2 using the analytical procedure of ASCE 7-10 and NYCBC referred to 2009 NEHRP Recommended Seismic Provisions: Design Examples (2012) .
Figure 1. Berkeley Building Example
Dimensions : 102 ft 6 in x 212 ft 6 in in plan
Input value of BDS
Properties | Input | Properties | Input | ||
|---|---|---|---|---|---|
Site Class | C | Seismic Force-Resisting System | SpecRCMomFrameC | ||
Ss | 1.65 | Lateral Force-Resisting System | ConcreteMomentResistingFrames | ||
S1 | 0.68 | Seismic Design Category | D | ||
Tl | 6 | Occupancy Category | Category2 | ||
R | 8 | - | - | ||
Omega | 3 | - | - | ||
Cd | 5.5 | - | - | ||
Seismic Response Parameters
Parameters | Hand Calculation | Building Design Suite |
|---|---|---|
Fa | 1.2 | 1.2 |
Fv | 1.7 | 1.7 |
Sms | 1.98 | 1.98 |
Sm1 | 1.156 | 1.156 |
Sds | 1.32 | 1.32 |
Sd1 | 0.7707 | 0.7707 |
Ts | 0.5838 | 0.5838 |
Story Weights and Masses
Floor | Weight, kips |
|---|---|
Roof | 3352 |
12 | 3675 |
11 | 3675 |
10 | 3675 |
9 | 3675 |
8 | 3675 |
7 | 3675 |
6 | 3675 |
5 | 3675 |
4 | 3675 |
3 | 3675 |
2 | 3817 |
Total | 43919 |
Development of Equivalent Lateral Forces
Parameters | Reference | Building Design Suite |
Ta | 1.55 | 1.5498 |
Cu | 1.4 | 1.4 |
Tmax | 2.17 | 2.17 |
Ct | 0.016 | 0.016 |
x | 0.9 | 0.9 |
Seismic Response Coefficient
Seismic Response Coefficient | Hand Calculation | Building Design Suite |
Cs,max | 0.0622 | 0.0622 |
Cs | 0.165 | 0.165 |
Cs,min | 0.0581 | 0.0581 |
Vertical Distribution of N-S Seismic Forces for the Berkeley Building
Building Desing Suite | ||||
Level | Height, ft | Weight, kips | Fx, kips | Oveturning Moment, ft-k |
Roof | 161 | 3352 | 467.7247 | - |
12 | 148 | 3675 | 451.0117 | - |
11 | 135 | 3675 | 392.0149 | - |
10 | 122 | 3675 | 335.9291 | - |
9 | 109 | 3675 | 282.8983 | - |
8 | 96 | 3675 | 233.0909 | - |
7 | 83 | 3675 | 186.7082 | - |
6 | 70 | 3675 | 143.9968 | - |
5 | 57 | 3675 | 105.2685 | - |
4 | 44 | 3675 | 70.9363 | - |
3 | 31 | 3675 | 41.5861 | - |
2 | 18 | 3817 | 18.8541 | - |
Total |
| 43919 | 2730.0196 | 3254988.0118 |
Verification object link
Figure 2. Honolulu Building Example
Dimensions : 102 ft 6 in x 212 ft 6 in in plan
Input value of BDS
Properties | Input | Properties | Input | ||
|---|---|---|---|---|---|
Site Class | C | Seismic Force-Resisting System | IntRCMomFrameC | ||
Ss | 0.61 | Lateral Force-Resisting System | ConcreteMomentResistingFrames | ||
S1 | 0.18 | Seismic Design Category | D | ||
Tl | 6 | Occupancy Category | Category2 | ||
R | 5 | - | - | ||
Omega | 3 | - | - | ||
Cd | 4.5 | - | - | ||
Seismic Response Parameters
Parameters | Hand Calculation | Building Design Suite |
|---|---|---|
Fa | 1.2 | 1.2 |
Fv | 1.7 | 1.7 |
Sms | 0.732 | 0.732 |
Sm1 | 0.306 | 0.306 |
Sds | 1.32 | 1.32 |
Sd1 | 0.7707 | 0.7707 |
Ts | 0.5838 | 0.5838 |
Story Weights and Masses
Floor | Weight, kips |
|---|---|
Roof | 3352 |
12 | 3675 |
11 | 3675 |
10 | 3675 |
9 | 3675 |
8 | 3675 |
7 | 3675 |
6 | 3675 |
5 | 3675 |
4 | 3675 |
3 | 3675 |
2 | 3817 |
Total | 43919 |
Development of Equivalent Lateral Forces
Parameters | Reference | Building Design Suite |
Ta | 1.55 | 1.5498 |
Cu | 1.5 | 1.496 |
Tmax | 2.35 | 2.35 |
Ct | 0.016 | 0.016 |
x | 0.9 | 0.9 |
Seismic Response Coefficient
Seismic Response Coefficient | Hand Calculation | Building Design Suite |
Cs,max | 0.0263 | 0.0263 |
Cs | 0.0263 | 0.0263 |
Cs,min | 0.0215 | 0.0215 |
Vertical Distribution of N-S and E-W Seismic Forces for the Honolulu Building
Building Desing Suite | ||||
Level | Height, ft | Weight, kips | Fx, kips | Oveturning Moment, ft-k |
Roof | 161 | 3352 | 198.0952 | - |
12 | 148 | 3675 | 191016.7 | - |
11 | 135 | 3675 | 166.0298 | - |
10 | 122 | 3675 | 142.2759 | - |
9 | 109 | 3675 | 119.8157 | - |
8 | 96 | 3675 | 98.7208 | - |
7 | 83 | 3675 | 79.0764 | - |
6 | 70 | 3675 | 60.9869 | - |
5 | 57 | 3675 | 44.5843 | - |
4 | 44 | 3675 | 30.0436 | - |
3 | 31 | 3675 | 17.6129 | - |
2 | 18 | 3817 | 7.9853 | - |
Total |
| 43919 | 1156.2436 | 137857.9815 |
Verification object link