Seismic Base Shear Example

Calculation the seismic base shear of a 12-story reinforced concrete office building illustrated in Figure 1 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

https://bim.aecbolt.com/platform/?application=inc&author=Verification_Examples_AEC%7CBOLT%2C+Inc&folder=Seismic+Base+Shear&obj=objid0me5wwkumthp2gorgfi2rh