CE 463.3 – Advanced Structural Analysis Lab 1

COLLEGE OF
ENGINEERING
Department of Civil & Geological Engineering
CE 463.3 – Advanced Structural Analysis
Lab 1 – Introduction to SAP2000
January 09th, 2013
T.A: Ouafi Saha
Professor: M. Boulfiza
Objectives:
• Give an over view of the basic commands of SAP2000
• Use of SAP2000 to solve various structural problems
• Develop the ability to continue a self-learning process
• Check and solve assignment questions
1. Introduction to Computation Modeling in Engineering:
Conceptual Design
Modeling
Physical, Mathematical, Computational
Operational and Economical
Simulation
Experimental, Analytical and Computational
Analysis
Listing, Photography,
Computer graphics and Virtual reality
Design
Prototyping
Testing
Fabrication
Engineering process from Conceptual idea to Fabrication
(The Finite Element Method – A Practical Course. by G.R. Liu, S.S. Quek)
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2. Computation Hardware tool:
Input
Central Unit
Output
Simplified scheme for Computer
3. Computation Software tool:
Pre-Processor
Import, Interactive
Processor
Interpretation of data, Detection of Errors,
Formation of Sys. Eq., Solve Sys., Iteration
Post-Processor
Visualization, Design
Simplified scheme of a computer software
4. SAP2000:
SAP2000 is a program based on The Finite Element Method (FEM). It is one of a long list of software
packages having the FEM as their kernel. A non-exhaustive list is available at this address:
http://en.wikipedia.org/wiki/List_of_finite_element_software_packages
The program is edited by a company named CSI (Computer and Structure Inc.) founded in 1975. The
very first version of SAP was SAP, followed later by SOLIDSAP and SAP IV. With the development
of PC computers, SAP was released in two major versions SAP80 and SAP90. Basically these two
versions and the previous ones were based on TEXT files for both input and output. In 1996 the first
version of SAP2000 was released, it had an integrated graphical user interface working completely
under Microsoft Windows.
The choice of SAP2000 in this course is mainly due to its civil engineering orientation and to its
relative ease of use. SAP2000 has an integrated graphical user interface similar to some older versions
of Autocad’s interface.
Various documents and tutorials are available:
• Built-in help and PDF documentation.
• http://www.csiberkeley.com/sap2000/watch-and-learn
• A search in google or youtube with keywords “sap2000 tutorial” leads to plenty of documents
and videos, but try to start with the easiest ones.
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5. Basic Steps to Solve a Structural Problem using SAP2000:
1. Start-up by choosing units, setting up grids or by choosing a model from the library
2. Define materials, element properties, loading patterns, analysis cases and combinations
3. Draw the model using the powerful graphical interface and selection and editing tools
4. Assign displacement boundary conditions (supports)
5. Assign loads (forces, moments, displacements, pressure, temperature…)
6. SOLVE system, use simplification if possible
7. Display Output in graphical and/or tabular form
8. Analyze results
6. Examples:
6.1. Simply supported beam http://www.youtube.com/watch?v=IrYnpP2vDp0
Units kN, m, C
Material Concrete, Section 30x50cm2, each segment is 1.5m,
Two possible ways to model
Steps:
Start SAP2000 by using: internet explorer pointing at the url address http://www.engr.usask.ca/vdi/ or
http://www.engr.usask.ca/engr-apps/ , you can also save the link to your desktop and execute it.
Login using your nsid.
Choose New model
> select appropriate units and click on grid only
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In the next dialog box enter the appropriate values
Close 3D window and choose
view for the 2D view
Select Define > Section Porpertires > Frame Sections… then click on Add New Properties
Select Concrete and Rectangular section
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Name the section Beam and enter 0.5 as Depth and 0.3 as Width
Click on Ok twice
as five consecutive elements, starting from the origin to each next key point, make
Draw the Beam
sure the section in the flying box is Beam. End drawing by esc or double click.
Select Node B, Assign > Joint > Restraints… then select
Select Node F, Assign > Joint > Restraints… then select
Try a quick run and see how to neglect self-weight http://www.youtube.com/watch?v=xajE-OhAut8
Select Element A-B, Assign > Frame Loads > Distributed… enter 15 under Uniform Load
Select Element B-C, Assign > Frame Loads > Distributed… enter 15 under Uniform Load
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Select Node D, Assign > Joint Loads > Forces… enter -45 in Force Global Z
Select Node E, Assign > Joint Loads > Forces… enter -22.5 in Force Global Z
Before Solving, take a look at the final configuration, and particularly loading
Menu Display > Show Load Assigns > Frame/Cable/Tendon…
The screen should show a beam like the following
Our beam can be treated in two dimensions as a 3 DOF system. This can considerably reduce the size
of the problem for a very fine mesh (high number of elements and nodes).
Menu Analyze > Set Analysis Options… Click on Plane Frame
You can see that the only active DOF’s available are the two translations X and Z and one rotation RY.
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Now we can run the Analysis
or F5 or Menu > Analysis > Run Analysis…
Make sure to turn off the analysis of Modal Case
Click on Run Now
You will be prompted to save your work if it has not been done yet.
It is recommended to save your work on a regular basis.
Now, it is time to analyze our results and decide if they are acceptable or need to be reviewed in some
way.
Check deformed shape,
Support reactions
Internal forces and moments
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6.2. Simply supported Beam http://www.youtube.com/watch?v=tYOByVFtGRU
12m
Units kN, m, C
Neglect self-weight
8m
Material E=200 000 MPa, Section I=2000 106 mm4, find vertical displacement at the concentrated load.
The model definition is done following the same steps as in the previous examples. However, three
specific points need more details.
Material definition:
Go to menu Define > Materials … then click on Add New material
Material name
Based on Other
Put 0 to avoid
self-weight
E=200 000 MPa
Same as 200e9 n m
Section definition:
Menu Define > Section Properties > Frame Sections … then click on Add New Property …
Section type
Other
General
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All values can be 0
except
6
4
I33=2000 10 mm
Change default
name FSEC1 to
your preferred
Select Material
MAT defined in
previous step
Make sure your beam has the section SEC defined above and that this section is made of the particular
material MAT. Make sure to not include self-weight as well by putting material weight = 0.
Neglect self-weight
Menu Define > Load Patterns …
Change Self Weight Multiplier to 0 in the DEAD load pattern and click on Modify Load Pattern, then
OK.
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Run your Analysis. Then display the moment diagram.
Show Forces/Stresses >
Frames/Cables …
Choose Moment 3-3
Location 12m
Deflection
0.0384m
Usually we use
Absolute. But for
this example there
is no difference
A better way to do it is by defining our structure with nodes at the desired locations, if necessary. In
this case add a node at the location 12m.
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6.3. Simply loaded Frame
4m
4m
C
4m
2m
A
Material E=200 000 MPa
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4
Geometrie I = 500 10 mm
2
A = 2000 mm
At least two ways to define our structure are possible; with and without a node at point C.
The steps to define the structure are almost the same as in the previous examples. Unit and Grid;
Material and Section (don’t forget to add the cross section A); Draw the structure either with a step
at point C or without; Support and Loads; Analysis of Plan Frame.
then put the
For the horizontal displacement at point A click on the Show Deformed Shape button
mouse pointer close to the point A, a bubble appears showing information about that point, the
horizontal displacement parallel to X axis is U1 = -0.008 (in this case in the opposite X direction)
because local and global axis have the same orientation for the nodes.
You can also right click on the node to see these values more precisely in a box.
These values are given relatively to the undeformed shape.
Point A (U1=Ux=-0.008, U2=Uy=0, U3=Uz=-0.09117, R1=Rx=0, R2=Ry=0.012, R3= Rz=0)
Displacements are given in the distance Unit, Rotations are given in radian according to the right hand
rule.
With a node at C
We can use the grid system X (0, 4, 8) and Z (0, 2, 4). We are not using the Y axis so fare.
The steps to find the vertical displacement at point C are the same as those for point A, the only
difference is to look for U3 = -0.04317 in the negative Z direction.
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Without a node at C
We can use the grid system X (0, 8) and Z (0, 2, 4).
In this case we do not have a node at point C and the determination of the vertical displacement is done
by displaying the information of the horizontal element (8m beam). For this purpose show the moment
3-3 diagram.
Then right click on the horizontal element. To show the detailed results
Select mid-span
Select Absolute to get
vertical displacement
with respect to the
global axis (XYZ)
Note: positive in -2
direction
If you get a little difference with the hand calculated values try to explain why.
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