User Guide

RISA-3D User’s Guide
Version 5.0
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The combinations that were entered in the spreadsheet may be edited. We will
explain all of the fields before going further.
The first field, the description, is strictly for your reference. You may enter any
descriptive label that you wish and it will be displayed with the results when the
load combination is solved.
The Solve checkbox indicates whether this combination is to be included in the
Batch or Envelope solution. RISA-3D allows you to solve a single load
combination, a batch of combinations or an envelope of multiple combinations.
The Batch solution allows you to solve multiple combinations and review all the
results together. The Envelope solution solves multiple combinations keeping
only the maximum and minimum values in the results. All of our combinations
are currently checked to be included.
The PDelta flag indicates what type of P-Delta analysis you wish to run. P-Delta
calculations account for the secondary effects resulting from load eccentricities
due to model deflections.
The SRSS field is used to combine response spectra analysis results for different
directions by taking the square root of the sum of the squares.
The remaining fields define the actual combinations with pairs of BLC columns
and Factor columns. The values should look familiar to you since they are just as
they are listed in the code.
Instead of using categories, as we have here, you may also list loads by the BLC
number. For example instead of using “LL” we could call the same load by using
the number “3”. Other options include nesting one combination within another
and including response spectra results. See the General Reference or the on-line
help file for more on this.
We will make some changes before moving on. Since we do not have an
earthquake load, snow load or rain load we will remove these combinations from
the list. We will do this by deleting lines from the spreadsheet.
Select lines 7 through 16 by clicking the mouse on the button on the left side of
row 7 (the button with a “7” on it) and drag the mouse to the button for row 16
before releasing.