Complex Diaphragms With Combined Openings and Offsets - The Analysis of Irregular Shaped Structures - page 310

Section B:

d 300

2

d = 25 12 () = 30 in − 15 . ′′ = − 15 . = 148 5 . in

2

I 3 = 2165 298 52940 374 (. )( .)

2

= , , in

4

L = 15 ft

1

w = 105 plf

A short member is installed at the right end of sections A and B to separate the two
members and connect them to the member between grid lines A and C, which has a
moment of inertia equal to I 1 . The support condition for section A is a pinned connection.
The support conditions for section B and the right end of the longer member at grid line A
are rollers.
The computer output shows that the reaction to grid line A is 21,253 lb. The reaction
to section A (SW6) is 14,623 lb, and the reaction to section B (SW7) is 3954 lb.
Construction of the basic diaphragm shears starting at grid line C:

VR = + R − 2 wx = 14 623 , + 3954 − 2 105 1 ( )( 5 )

C sectA sect B

=+ 15 427 , lb shearatgrid lineC

V
D

15 427
70

,

C

V == =+ 220 39 . plfunitshear at grid lineC rightside ( )

CR

VVwx
BL

=−= 15 427 , − 294 35 ( ) =+ 5137 lb shearat grid lineB left side ( )

C

V
D

5137
70

BL

v = = =+ 73 39 . plfunitshear at gr id lineB left side ( )

BL

VVP
BR

=−= 5137 − 14 631 , =− 9494 lb shearatgri d lineB rightside ( )

BL

V
D

= −

9494
70

BR

v = = 135 63 . plfunitshear at g rid lineB rightside ( )

BR

V A =−21 253 , lb shearatgrid lineA

= −

21 253
70

,

v A = 303 61 . plfunitshear at grid lineA

Section A (see Fig. 8.23): The total shear distributed to shear wall SW6 from the main
diaphragm through section A is 14,623 lb. That shear will be distributed through the area
bounded by grid lines 6 to 7 from C to E.

V = 14 623 , lb = V

E

67 −

14 623
25

,

v E = = + 584 92 . plf

VVwx
CE

=−= 14 623 , − 105 15 ( ) = 13 048 , lb

V
D

13 048
25

,

C

v == =+ 521 92 . plfunitshear at g rid lineC left ( )

C