Civil Engineering Reference
In-Depth Information
Although it would seem that by reducing the number of shear walls in the structure, the
client could save money, in actuality the costs are simply shifted from the walls into the
diaphragm. A large part of those costs is from the additional collectors and connections
required to complete the complicated load paths. Often the costs can actually be greater
than by installing more walls to eliminate or lessen the impact of the irregularities and
in turn increase redundancy.
Figure 8.30 shows the same diaphragm with wind loads applied. The reader is
encouraged to solve this problem so that a comparison can be made with seismic
loading.
8.5
Alternate Layouts
The configuration of the shear walls, openings, and offsets in the diaphragm makes
it difficult to eliminate all the irregularities by adding more walls. However, there
are several possible combinations of wall arrangements that can simplify the lat-
eral system. These options should be thoroughly investigated in the schematic
phase of the design and reviewed with the client. An excellent set of exercises
would be to analyze the diaphragm shown in Fig. 8.30 for each of the following
modifications:
1. Add a 12 ft shear wall at grid lines 2 and 8, transverse loading.
2. Add an 8 ft vertical offset at grid line 5, transverse loading.
3. Add a shear wall along grid line B from 6 to 8.
4. Remove shear walls SW6 and SW7 and add a shear wall at grid line C from 7
to 8.
5. Remove shear walls SW4 and SW8 and add a shear wall at grid line A.2 from 3
to 5.
6. Make your own configurations.
Each of these exercises will provide its own special lesson regarding the develop-
ment of complete load paths and the transfer of forces across discontinuities.
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