|
|
|
|
|
User-input dead loads are to be manually calculated from distribution of area loads from floors and roofs to line loads on walls. It is also possible to specify the load supported by walls and/or the wall self-weight and have the program generate these loads.
Load Combination Factor
For wind design of hold-downs, the counteracting factor 0.9 from NBC Table 4.1.3.2.-A, Case 4, is applied to the dead load component of tension force, as per NBC 4.1.3.2.(5), and the factor 1.25 is applied for compressive design at the other end of the segment. For seismic design, a factor of 1.0 is applied at both the tension and compression ends, as per Table 4.1.3.2.-A, Case 5.
For the hold-down elongation and wood crushing terms in the deflection calculation, a factor of 1.0 is used, as per O86-14 5.2.4.2. combination 5.
Building Masses vs Dead Loads
IMPORTANT: The generation of building masses for seismic load generation does not affect the value of dead loads on shear lines for hold-down force calculations. Because Shearwalls does not at present have a gravity load distribution system to determine which elements support the building mass of the floors, it is necessary to apply the dead loads directly on the wall lines as line loads resulting from the area and loads on roofs and floors. This can be done manually on each shearline, or you can generate dead loads on the shear lines using the wall self-weights and supported weights you have assigned to each wall or shearline.