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CE 432 / 532 Spring 2007 RISA Frame Design Procedures 1 / 6

Table of Contents 1) Define your Sections for each type of member ...................................................................... 1

2) Draw your members................................................................................................................ 2

3) Set the Boundary Conditions .................................................................................................. 3

4) Input the Loads ....................................................................................................................... 4

5) Analyze the structure for the appropriate loads to compare with hand-calculations.............. 5

1) Define your Sections for each type of member

a) Display the “Data Entry” menu if it is not already displayed by clicking on the “D” icon

After solving a load combination, RISA should display the “Results” menu. If it doesn’t, you can click on the “R” icon

b) Click on “Section Sets” and type a label (e.g. “Joists”)

c) Specify the type of material


2) Draw your members

a) Turn on the “graphic editing” toolbar if it is not already by right-clicking anywhere in the middle of the screen and selecting the third item on the drop-down list.

b) Click on “Modify the Drawing Grid” icon

and type in the spacing of your joints

also specify to show grid as “Points”

c) Click on the “Draw new members” icon

Select “Assign a Section Set”

and select the appropriate set from the drop down list

Also select the appropriate member-end release codes

Click “Apply” and draw your members from node to node.


You can check that your sections are correctly assigned to your members by clicking “Plot Options”,

then “Members”, then ”Section Set” under “Labeling”.

3) Set the Boundary Conditions a) Click on the “Boundary

Conditions” icon

b) When modeling a 2-D tstructure in RISA3D, you must always restrain the model from moving out of plane. Select “Fixed” for the following displacement components: • Z Translation • X Rotation • Y Rotation

Click “Use?” for each,

Then “Apply Entries to All Selected Joints”

Then “Apply”


c) Set the boundary conditions for the supports as appropriate. For example, for a pinned joint select “Reaction” for X-Translation and Y-Translation.

4) Input the Loads a) Set up the Basic Load Cases and the Load Combinations

It’s a good idea to set up separate basic load cases without self weight and with self weight

RISA will include the self weight of all members in your model when you type a “-1” under “Y Gravity”

Combine the appropriate basic load cases in the Load Combinations dialog box. If you later want to analyze several Load Combinations at the same time, check the “Solve” box next to each load combination you want to include”

b) Input the loads for each load case graphically.

Input loads at the joints using “Joint Loads” and loads between joints using “Point Loads”.

Be careful to specify the correct Basic Load Case before drawing the loads.


5) Analyze the structure for the appropriate loads to compare with hand-calculations. a) Turn off shear deformations when

running RISA to compare against your hand calculations. Click on “Global” then the “Solution” then uncheck the “Shear Deformation” and “Torsional Warping” boxes

b) Analyze the load combination that does not include self weight.

c) If this is the first time you’ve analyzed the model, it’s a good idea to check the deflected shape of the structure. This can catch a multitude of different errors.

Click on “Plot Options”

Then “Deflection Diagrams”

The “Load Combination”

You may need to increase the Magnification Factor


d) Display the appropriate member force (axial forces, shear forces or bending moment) to compare with the hand-calcs.

Click on “Plot Options”

“Members”

“Axial” under “Member Results”

“Outline”

“Magnitudes”

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