Draft

2.3LateralLoads 45

5. Thetotalverticalloadis

W= 2 ((200+ 0:5(400))(20)= 16000lbs (2.17)

6. Thetotalseismicbaseshearis

V =

ZIC

RW

=

(0:3)(1:25)(2:75)

12

= 0: 086 W (2.18-a)

= (0:086)(16000)= 1375 lbs (2.18-b)

7. 
   

   SinceT < 0 :7 sec.thereis nowhiplash.

   
   


8. 
   

   Theloadoneach
   oor is thus givenby

   
   

F 2 =

(1375)(24)

12 + 24

= 916.7lbs (2.19-a)

F 1 =

(1375)(12)

12 + 24

= 458.3lbs (2.19-b)

Example2-4: Earthquake Loadona TallBuilding,(Schueller1996)

Determinetheapproximatecriticallateralloadingfora 25 storey, ductile,rigidspaceframe

concretestructurein theshortdirection.Therigidframesarespaced 25 ft apartin thecross

sectionand20 ft in thelongitudinaldirection.Theplandimensionof thebuildingis 175x100ft,

andthestructureis 25(12)=300ft high.Thisocebuildingis locatedin an urbanenvironment

witha windvelocity of 70 mphandin seismiczone4. For thisinvestigation,an averagebuilding

totaldeadloadof 192psfis used.Soilconditionsareunknown.

470 k

2638 k

1523 k

2(300)/3=200’

300/2=150’

25(12)=300’

84000 k

3108 k

5(20)=100’

7(25)=175’