Diaphragms With End Horizontal Offsets - The Analysis of Irregular Shaped Structures - page 118

Complex diaphragms should be analyzed in both the transverse and longitudinal
directions to ensure that the maximum chord, strut, or collector forces have been deter-
mined. Neglecting to do so can lead to the failure of a significant component. The next
two examples that follow address the analysis of the previous diaphragm loaded in the
longitudinal direction. Each example demonstrates a load path problem that occurs
when support walls are placed at different locations within the diaphragm. Example 3.2
assumes that shear walls occur at grid lines A and C only, which creates a discontinuity
in the strut at the offset. The strut is offset inward. In Example 3.3, shear walls are
placed at grid lines A, B, and C, which creates an offset shear wall condition. The walls
at lines B and C are assumed to act in the same line of lateral force resistance.
Example 3.2: Single Notched Diaphragm, Longitudinal Loading, Strut Offset in
The diaphragm shown in Fig. 3.20 can be designed by assuming that the smaller section
of the diaphragm located between grid lines A and B from 1 to 2 acts as an independent
diaphragm section. Both ends of this section are supported by struts that are tied into
the main diaphragm that lies between grid lines A and C. The strut at line B supports
one end of the diaphragm and extends into the transfer diaphragm that occurs between
F i g u r e 3.20 Single notched diaphragm, analysis in the longitudinal direction.