Complex Diaphragms With Combined Openings and Offsets - The Analysis of Irregular Shaped Structures - page 280

F i g u r e 8.6 Segmentation of the diaphragm for longitudinal loading.

diaphragms TD1 and TD2. Diaphragm section 4 is supported by shear walls located at
grid lines A and D. The chords for diaphragm 4 are located along grid lines 4 and 6.
Diaphragm 5 is supported by shear walls at grid line D and by the strut at grid line B.
The strut is connected to a collector that is embedded in diaphragm 4. The shear walls
at grid lines C and D are offset and assumed to act in the same line of resistance.

8.3 Analysis in the Transverse Direction

The diaphragm in Example 8.1 is similar to the previous diaphragm except that addi-
tional offsets and interior shear walls have been added. The diaphragm will be ana-
lyzed in both the transverse and longitudinal directions. For loading in the transverse
direction, the diaphragm is broken down into two separate diaphragms. Diaphragm 1
is supported by shear walls at grid lines 1 and 6, which has two horizontal offsets and
a large opening. Diaphragm 2 is supported by the shear walls at grid line 6 and by the
moment-resisting frame at grid line 10. This diaphragm section has an intermediate
notch and an end offset. The beams located at grid line B are full length of both dia-
phragms and will be used as collectors or chords to tie the individual sections
together.

Example 8.1: Complex Diaphragm, Analysis in the Traverse Direction
The diaphragm shown in Fig. 8.7 is 190 ft long by 90 ft deep. The shear wall at grid
line 1, SW1, is 20 ft long and contains an opening. Shear walls SW2 and SW3, located at
grid line 6, are 25 and 10 ft long, respectively. The lateral-force-resisting element at grid
line 10 is a 40 ft long moment-resisting steel frame. Assuming that wind controls the
design, a uniform load of 200 plf is applied to one side of the diaphragm sections that