...
How
...
do
...
I
...
obtain
...
collector
...
forces
...
within
...
a
...
floor
...
diaphragm?
...
Answer:
...
The
...
collector
...
forces
...
within
...
a
...
floor
...
diaphragm
...
may
...
be
...
measured
...
through
...
the
...
following
...
process:
...
- Define a semi-rigid
...
- diaphragm,
...
- then
...
- apply
...
- diaphragm
...
- forces,
...
- as
...
- shown
...
- in
...
- Figure
...
- 1:
- For a given load case, display any stress or shell force, as shown in Figure 2:
- Where maximum chord forces are expected, draw or define a section cut, as shown in Figure 3:
- Moments about the Z-axis represent in-plane moments. Ensure that the resultant-force angle is 90 in order to enforce vertical line, then select Refresh, as shown in Figure 4:
- Compression and tension chord forces are then given as the value of each Z-axis moment divided by slab width, as shown in Figure 5:
- For shear and collector forces located at the connection between the diaphragm and a shear wall, draw or define a section cut next to the support which follows the wall direction, as shown in Figure 6:
- Again, ensure that the resultant-force angle is 90, and refresh as necessary. Given this example model, the shear/collector force, which is presented in F1, is 2559 lbs., as shown in Figure 7:
- Local axis of section cut 1, 2 and Z are similar to a frame element, resultant force angle indicates angle between X global axis and section cut local 1 axis
See Also
- Rigid vs. semi-rigid diaphragm article
- Accidental eccentricity design article