S T R A P
***ATIR***
STRAP
for
Windows
STRUCTURAL ANALYSIS
PROGRAM
TUTORIAL
&
DEMO
Examples
- Metric units -
Version 11.5
December 2004
Version 11.5
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STRAP
Disclaimer
The STRAP programs have been written by a team of highly qualified engineers and programmers and have
been extensively tested. Nevertheless, the authors of the software do not assume responsibility for the validity
of the results obtained from the programs or for the accuracy of this documentation.
The following examples demonstrate various program options used for
defining the geometry and loads for structural models and for
displaying their results. These examples were designed as teaching
aids only and should not be considered as a guide for accurate
modeling of similar structures
The authors remind the user that the programs are to be used as a tool for structural analysis, and that the
engineering judgement of the user is the final arbiter in the development of a suitable model and the
interpretation of the results.
The user must verify his own results
Windows is a registered trademark of Microsoft Corp.
AutoCAD is a registered trademark of Autodesk Inc.
Acrobat is a registered trademark of Adobe Systems Inc.
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Table of Contents
1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
1.1
Installing the Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
1.2
Hints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
2 Demo examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
2.1
Demo 1 - Plane Frame . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
2.2
Demo 2 - Plane Grid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-8
2.3
Demo 3 - Space Frame . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-12
2.4
Demo 4 - Chess Loads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-17
2.5
Demo 5 - Finite element results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-20
2.6
Demo 6 - Result Combinations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-22
2.7
Demo 7 - Structural steel design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-25
2.8
Demo 8 - Reinforced concrete design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-29
2.9
Demo 9 - Light gauge steel design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-32
2.10
Demo 10 - Bridge loading analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-37
2.11
Demo 11 - Bridge analysis – Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-39
Miscellaneous . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-58
3.1
Defining new models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-58
3.2
How to Use HELP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-59
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1 General
This DEMO version is a limited version of the STRAP analysis and design program.
New models with up to 12 nodes may be defined, solved and saved. For instructions, refer to section 3.1.
The DEMO includes:
• the files of 11 existing models; these models already contain more than 12 nodes and additional nodes may
be defined. However, revisions to the geometry and loading will not be saved.
• detailed instructions for defining the geometry or loading of models or viewing their results (Demo 2.1 to
Demo 2.11).
The 11 existing models are:
•
“DEMO - Empty model” :
an ‘empty’ model i.e. it contains no existing geometry. It may be used to define any model up to the program
capacity (32,000 nodes), e.g. the models in Demo 2.1, Demo 2.2 and Demo 2.3. However the geometry
will not be saved.
•
“DEMO 4...” to “DEMO 11...” :
the models corresponding to Demo 2.4 to Demo 2.11. These Demo examples describe the definition of
loads, viewing of results and use of the design postprocessors.
•
“Ramp”, “Stadium”, etc.
4 large solved models, intended primarily for displaying results.
Note:
• The Windows version of STRAP provides the user with extensive on-line Help; the entire User's Manual
is an integral part of the program and may be displayed at any time. For instructions, refer to section 3.2.
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1.1
Installing the Program
Before starting the program installation, make sure that you have all the hardware required to run STRAP:
• A personal computer with Windows 95/98/2000/NT
• At least 35 MB of free space on your hard disk
The files on the STRAP installation diskettes or CD are in compressed format; they are copied to the hard disk
by an installation program. The program cannot be installed by copying the files from the diskettes or CD.
To install the program::
•
•
•
Insert the CD in its drive.
Follow the instructions on the CD case back cover
Follow the instructions displayed on the screen:
Then define the program directory and select the modules to be installed:
The program should be installed in a separate directory (the installation program will open a new directory if
the directory with the name entered does not exist).
To change the program folder, click
Set the required program modules
to , Note that the entire program
does not have to be installed, a
useful feature for updates.
Click
installation.
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1.2
•
Hints
Help
Note that Help is available at any point by pressing the
for the current option. Refer to 3.2.
key; the program will display the manual page
•
Undo
If you made a mistake, simply click the Undo option in the menu bar at the top of the screen; the program
will delete the previous definition step.
•
Icon bar
Note the row of small icons below the menu bar at the top of the screen. Clicking an icon provides access
to many of the program options. Place the on an icon to display a ‘hint’ explaining its function.
•
Zoom
Click the Zoom option in the menu bar at the top of the screen and try the Number of Windows option.
This option creates a ‘split screen’ showing different views of the model. Each view can be rotated to a
different angle, have a different zoom and display different information.
Any of the windows may be the ‘active’ one; move the into a window and double click the mouse. When
you define part of the geometry in the active window, all of the other windows are updated simultaneously.
•
Display
Click the Display option in the menu bar at the top of the screen to display various information about the
model - node, beam and property group numbers, support location and type, spring location, etc.
Verify node coordinates by selecting Define/revise dimension lines; the program will display the distances
between nodes that you select. The lines may be vertical, horizontal or parallel to any pair of nodes.
•
Print graphics
Select the Output option on the menu bar and click on Print drawing. The current display will be printed
to the scale and with the title that you define.
•
File management
The program provides complete file management capabilities (backup, restore, delete, etc.); select the Files
option in the menu bar in the program’s initial screen (STRAP models list).
•
Create your own model
To create a new model of your own, simply Exit to the STRAP models list, select Files in the menu bar and
click New model. Remember that only models with 12 nodes or less can be saved in the Demo version.
Refer to 3.1.
Try the Models wizard option - you only have to type in a few parameters to create standard structural models.
Note that the models available in the preprocessor are dependant on the Model type specified - click the
Wizard button and the program will display the models that may be defined.
•
Beam/element properties
Beam properties (section properties, dimensions or steel section) are defined for property groups; each
beam is then assigned to a group. Revise the whole group instead of making tedious member by member
changes.
Click the Display option in the menu bar and select Property name to verify that the correct property was
assigned to all of the beams in the model.
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2 Demo examples
Select the STRAP icon in the Windows Program Manager screen:
The program Main Menu and model list is displayed. The model list initially contains the names of the models
supplied with the Demo. Remember that the geometry and loads of these models may be revised but the
revisions will not be saved.
To select an existing model:
• move the to the model name in the list and click the mouse; the model name will be highlighted.
• follow the detailed instructions in each of the Demo examples.
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2.1
Demo 1 - Plane Frame
Define the following plane frame using the Models wizard.
Demo 1 is a simple example that demonstrates the following:
•
Definition of a simple plane frame, using STRAP’s model wizard library.
STRAP contains a library of standard structures that enables the user to easily and quickly define the model
geometry and loads by entering a small number of parameters. The library can be extended to include
additional model types.
•
Utilization of STRAP’s “copy” feature for defining the diagonals in the upper stories.
STRAP’s “copy” commands are powerful and sophisticated. The program refrains from duplicating existing
beams. In our example, the program will duplicate only the diagonals and not the other existing members
(beams and columns).
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Define the model:
•
Main Menu
-
double-click DEMO - Empty model in the model list. This is an empty demo model that allows you to define
any size model up to the program capacity.
•
Preliminary Menu:
Arrange the menu as follows:
Revise the model units (if necessary)
Set the model type to Plane frame
Click
•
Model wizard:
-
Click
-
Define the plane frame parameters:
to continue
Type in the number of bays
Type in the number of storeys
Type in the bay width
Type in the storey height
Click the
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-
Define the section type for beams:
Click the
icon
Select American (if necessary)
-
Click UB in the section type list and 406x140x39 in the section list.
Select Steel
Define X3 as the major axis
Click the
button
icon and select UC and 356x368x129.
-
For columns, click the
-
Define dead, live and wind loads and load factors for combinations.
The model wizard creates standard load cases from the basic load data. For the plane frame wizard, nine
cases are created - Press
to display more details.
Note that loads defined by a wizard in the Demo version are not saved and cannot be displayed. Loads for
this frame are also defined in Demo 4.
-
Define dead and live load:
Type in the dead load value
Type in the live load value
Type in the self weight factor
Click the
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-
Define Wind loads:
Type in the wind loads
Click the
-
button
Define combination factors:
Enter the load factors
Click the
button
-
The program now creates the model according to the parameters and displays it on the screen with the
following Dialog Box at the bottom:
-
To revise the dimension of the third bay to 7.5 m, click the
-
Move the to the horizontal dimension line so that the dimension of the third bay is highlighted with the
rectangular blip; click the mouse.
button.
Enter the new dimension
Click the
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Select This dimension only
-
Press Esc (right click the mouse) to end the revision of dimensions.
-
Click the
•
Geometry
-
click
-
To define the bracing, click the
-
Click the
-
move the
into the Dialog box at the bottom of the screen and set Prop.= 3; click
-
move the
move the
adjacent to node 3 so that the node is highlighted with a
adjacent to node 9 so that the node is highlighted with a
button to leave the Model Wizard. The program now enters the regular geometry module.
in the menu bar to display the node numbers
icon in the Main menu
icon in the Beam options menu at the side of the screen
Screen
.
; click the mouse
; click the mouse
the program creates a beam linking nodes 3 and 9.
-
In a similar manner, create a beam linking nodes 4 and 8.
Copy the bracing to all floors:
-
Click the
icon
-
Click the
icon
- Click the
icon in the Copy options menu at the side of the screen
Click Individual nodes
adjacent to node 3 so that the node is highlighted with a
-
move the
-
Similarly select nodes 4, 8 and 9
-
after the node 9 has been selected, click the mouse again without moving the crosshair (or click the
End selection button in the Dialog box at the bottom of the screen).
-
Select the reference node: move the
mouse
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; click the mouse
adjacent to node 3 so that the node is highlighted with a
2-6
; click the
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-
Select the new location of the reference node: click the
button and select node 8.
Set Number of copies to 2
Select Automatic numbering
Select Automatic numbering
-
click
; the program creates and draws the new bracing
Define the section properties of the bracing:
-
Click the
icon.
-
Click the
icon.
-
Click the
icon.
Select 3 – Undefined.
Click Define/revise
-
click the
-
Click the
-
Click the
icon and select 2L and 150x150x10; click
button to complete the property definition.
icon
You have now completed the definition of the geometry and the loads. To select the next Demo model:
- click File in the top menu bar
- select STRAP model list in the pull-down menu.
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2.2
Demo 2 - Plane Grid
Define the grid of finite elements shown in Figure D.2.
Demo 2 demonstrates STRAP’s powerful features of automatically generating a mesh of elements. The user
can define an area of any shape (which may also include holes in it) and the size of the elements that he wants.
The program identifies existing supports (e.g. columns) and includes them in the mesh nodes.
When defining a mesh area adjacent to an already defined mesh, the program will take care of a smooth
connection between the elements of the two areas.
Figure D.2
•
Main Menu
double-click DEMO - Empty model in the models list. This is an empty demo model that allows you to define
any size model up to the program capacity.
•
Preliminary Menu
-
set the default Units to meter and kN , the Display width range from -5 to 60 and the Display height range
from -5 to 40 (if necessary).
-
set the Model type to
-
click the
•
Geometry
Grid
button
Define the grid of support nodes:
-
click the
icon
-
click the
icon
Select Equally spaced
and click the
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-
The base line starts at coordinates (0,0); type 0 (the cursor automatically enters the X1= box) and
press [Enter]. The cursor moves to the X2= box; type 0 and press [Enter]. Press [Enter] or click the
button.
(Alternatively - move the on the screen so that the coordinate in the Dialog box at the bottom of the screen are X1=0.
and X2=0.; click the mouse.)
-
The base line ends at coordinates (50,0); type 50 and press [Enter]. The cursor moves to the X2= box; type
0 and press [Enter]. Press [Enter] three times or click the
button.
(Alternatively - move the on the screen so that the coordinate in the Dialog box at the bottom of the screen are X1=50
and X2=0.; click the mouse.)
-
Specify 5 segments and click the
-
Define the nodes on the grid height line as Equally spaced and click the
-
The height line ends at coordinates (50,32.5); type 50 and press [Enter]. The cursor moves to the X2= box;
button
type 32.5 and press [Enter]. Press [Enter] three times or click the
button
button.
(Alternatively -
move the on the screen so that the coordinates in the Dialog box at the bottom of the screen are X1=50
and X2=32.5 (or dX1=0 and dX2=32.5); click the mouse.)
Specify 5 segments and click the
on the screen.
button; the program creates a grid of nodes and displays them
Note that nodes not attached to elements are ignored by the program.
-
Click the
icon.
Define the supports:
-
Click the
icon.
-
Click the
icon in the Restraints option menu at the side of the screen.
Click Select all nodes
the program creates the pinned supports ; click
on the nodes.
Version 11.5
in the icon bar at the to p of the screen to draw them
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-
Click the
icon.
Define the mesh of elements:
-
click the
icon
-
click the
icon
Select Generate nodes
Select Rectangular
and click the
-
button
Define the contour line enclosing the floor area:
move the adjacent to node A1 (Figure D.2b) so that the node is highlighted with a ; click the mouse.
Similarly select nodes A2 to A8 and A1 (again) to close the contour.
Click Define contour of a hole
-
move the adjacent to node B1 so that the node is highlighted with a ; click the mouse. Similarly select
nodes B2, B3, B4 and B1 (again) to close the contour of the opening.
-
Select
-
Arrange the mesh parameters menu as follows:
End contour definition
Set the Grid step to 2.0
Set the Grid step to 1.3
Set Align grid with existing nodes
Click the
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-
The program superimposes the preliminary mesh (6.0 x 4.0) on the area defined by the contour.
-
Click the
button.
The elements as displayed in Figure D.2b are generated. Note that the existing elements in the contour area
are erased.
-
button when the program asks Is the mesh OK?
Click the
Define the element thickness:
-
click the
icon.
-
double-click the 1 - Undefined line (all elements were assigned to Property Group no.1 by default)
-
Set the Thickness = 25 (cm.)
-
click the
-
Click the
-
Click the
button
End
button to complete the property definition.
icon
You have now completed the definition of the geometry.
To select the next Demo model -
click File in the top menu bar
-
select STRAP model list in the pull-down menu.
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2.3
Demo 3 - Space Frame
In Demo 3 we will define a space structure.
In this Demo you will learn how to use STRAP’s more advanced features to quickly and easily define this
complex space frame.
Note: You are advised to run this DEMO after trying Demo 1.
The demo demonstrates the following features of STRAP:
•
Definition of a single frame by using a Model Wizard (similar to Demo 1).
•
Duplication of the single frame to form the space model.
•
Definition of the transverse truss as a submodel, also using a model wizard.
The submodel feature enables to define part of the structure as a separate model and then add it to the main
model at specified locations. Similar to the Copy option, the program does not generate double members.
•
Working in two windows (split screen). The whole model is displayed in one window. In the other one, the
transverse truss is displayed and selected for duplication.
•
The Mirror option for copying the transverse truss.
To define the model:
•
Main Menu
-
Double-click DEMO-Empty model in the model list.
•
Preliminary Menu
-
Set the Model Type to
-
Click the
•
Models wizard
-
Click the Frame truss button
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Space frame
icon
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-
Specify the parameters:
Click the
Skip all
button
-
click
twice as we will not define section properties and loads in the Wizard.
-
The program displays the model, click
•
Copy the frame truss
-
click
in the menu bar to display the node numbers (note that it will be very convenient to switch the
node numbers on/off many times during the course of building this model; these instructions will not mention
it every time)
-
Click the
icon in the main menu.
-
Click the
icon in the copy options menu
-
Click the
-
Select a reference mode: move the
mouse.
-
Define the new location of the reference node:
-
Click the
-
Type the coordinates X1=0, X2=0, X3=8 in the box at the bottom of the screen.
-
Click
Select all nodes
by coordinates
to continue
button
adjacent to node 1 so that the node is highlighted with a
; click the
button
to continue
Set Number of copies = 3
For convenience in identifying nodes in parallel trusses,
set increment = 100
click the
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-
The program creates the new trusses. Click the
to rotate the model to the isometric view.
button in the icon bar twice and the
-
Click the
•
Restraints
-
Click
-
Click the
icon.
-
Click the
icon in the Restraints option menu at the side of the screen.
-
Click the
•
Definition of the transverse truss:
-
Click the
-
Click the
-
Click the
-
Define one bay only (4 panels):
icon.
in the icon bar; note that restraints we not copied. To define them on the copied trusses -
Individual nodes
button and select the 12 new base nodes.
icon.
Model wizard
button in the submodel menu
icon
Click the
-
the program displays the model, click
-
Click the
icon.
-
Click the
icon.
-
Click the
-
Click the
Select all nodes
button
to continue
The Wizard defines by default two support restraints (Click
is a submodel, we have to delete them.
Version 11.5
button once
in the icon to display them). As our structure
button
icon.
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Copy the truss to create 3 bays:
-
Click the
icon in the main menu
-
Click the
icon in the copy options menu
-
Click the
-
Select a reference node: move the adjacent to node 1 (lower left corner of the submodel) so that the node
is highlighted a ; click the mouse.
-
Define the new location of the reference node: click the
-
move the adjacent to node 5 (lower right corner of the submodel) so that the node is highlighted with a
click the mouse.
-
Set Number of copies = 2 and click the
-
Click the full drawing icon
Select all nodes
button
at an existing node
button
;
button; the program creates and draws the truss.
in the icon bar at the top of the screen.
Add the submodel to the main model:
-
Click the
icon.
-
Click the
icon.
-
Select reference nodes: move the
with a ; click the mouse
-
Select nodes 1 and 6
-
Define the new location of the reference nodes:
-
Select nodes 318 (the ridge of the bottom chord of the first frame), 18 (the ridge of the bottom chord of the
last frame) and 32 (the ridge of the top chord of the last frame) or type the node numbers in the Dialog box
at the bottom of the screen.
•
Duplicate the transverse truss
adjacent to node 22 (at lower right end) so that the node is highlighted
We will use the Zoom option - Number of windows - to simplify the node selection procedure.
-
Select Zoom in the menu bar at the top of the screen.
-
move the
-
move the adjacent to the right window and double-click the mouse or click the title bar; the “focus” will now
be on this right window (note that the title bar is shaded!)
-
Select Zoom in the menu bar.
-
Create a window about the transverse truss.
-
Select Remove in the menu bar at the top of the screen then select Limit display to a plane
-
Select any 3 nodes in the truss plane (nodes 318, 18, 32 for example)
adjacent to - Number of windows - and then click Display 2 geometry windows
Copy the transverse truss:
-
Click the
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-
Click the
icon in the copy menu.
-
Click the
-
Select a reference node: select node 318 (the bottom node of the transverse truss, at the near end).
Select all nodes
button
Define the new location of the reference node:
at an existing node
-
Click the
button
-
Move the adjacent to the left window and double click the mouse (to shift the focus to the left Window) then
select node 316 (two nodes to the left from node 318).
-
Set Number of copies = 3 and click the
•
Duplicate the transverse trusses to the other side
button
Complete the definition of the secondary trusses by creating a mirror image of the entire model!
-
Click the
icon.
-
Click the
-
Select a reference node: select node 301 (the bottom left node of the left leg)
-
Define the new location of the reference node:
-
Click the
-
Click the
Select all nodes
button
at an existing node
button and select node 346 (the bottom right node of the right leg).
button to copy the trusses
Please note that although we selected the entire model, the program copied the transverse trusses only
because it automatically eliminates double members generated by the command.
To select another model:
-
Click the File in the top menu bar.
-
Select STRAP models list in the pull-down menu.
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2.4
Demo 4 - Chess Loads
In this Demo we will create the following load cases for the frame defined in DEMO1:
This Demo demonstrates STRAP’s unique “Chess load” option that automatically generates the critical loading
cases from basic Dead load and Live load cases (a & b in the drawings).
The program by itself identifies the continuous beams and applies the dead load and live load to the appropriate
spans and with the correct load factors. The program is smart enough to identify intermediate nodes if defined
and ignore them when applying the load.
•
define the dead loads shown in Figure (a) in load case 1
•
define all live loads shown in Figure (b) in load case 2
•
use the program Chess loads option to automatically create load cases (c), (d) and (e).
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•
Main Menu
-
highlight DEMO 4 - plane frame - LOADS in the model list
-
Click the
•
Load case 1 - dead loads
-
Click the
-
enter the load case tile; type Dead loads and click the
-
specify
-
Click the
-
Specify
-
Select the “parallel” beam (the load will be applied only to beams parallel to this one); move the adjacent
to any horizontal beam so that the beam is highlighted with a ; click the mouse.
-
Type in the uniform load =-21 (check that Direction: FX2) and click
-
The program creates the loads and draws them on the screen. Click the
•
Load case 2 - live loads
-
Click the
-
enter the load case tile; type Live loads and click the
-
proceed as described for Load case 1, except enter a uniform load = -13
-
to define the point loads, click the
-
Click the
-
Click the
-
Select one of the exterior roof beams; move the adjacent to any horizontal beam so that the beam is
highlighted with a ; click the mouse. Repeat for the other exterior roof beam.
-
Click the
-
Type in the point load =-24 (check that Direction: FX2 and that Fraction = 0.5) and click
continue
-
The program creates the loads and draws them on the screen. Click the
•
Chess loads
Version 11.5
icon in the side menu.
icon.
Beam loads and click the
button
icon
icon.
Select only beams parallel to a beam and click the
Select all beams
button
to continue
icon.
icon.
button
icon
icon.
Individual beams
End selection
button
button
2-18
End
to
icon.
12/04
STRAP
-
Click the
icon in the main menu.
-
The program correctly assumes that load case 1 contains all of the dead loads and that load case 2 contains
all of the live loads. Correct the maximum/minimum load factors if necessary; click
-
The program displays the series of generated load cases; click
to continue.
to continue after each case.
Check the loads in the generated load cases:
-
Click the
icon in the main menu and select the load case to be displayed, or
-
select Output in the top menu bar, then Display load commands and select the load case to be displayed.
You have now completed the definition of the loads. To select the next Demo model -
click File in the top menu bar
-
select STRAP model list in the pull-down menu.
Version 11.5
2-19
12/04
STRAP
2.5
Demo 5 - Finite element results
For the plane grid defined in Demo 2, display graphic results for finite elements.
The graphic results for elements can be displayed in any one of three ways:
•
Results at element centres
display the model geometry with the numerical value of the result written at the centre of each element.
•
Contour map
display the model geometry with a contour map of the results superimposed. Each line of the contour map
gives the location of a specified value of the result.
•
Results along a line
display the results plotted along a section through the model.
For example:
Figure D5 - Finite Element Results
Version 11.5
2-20
12/04
STRAP
•
Main Menu
-
highlight Demo 5 - grid - mesh - RESULTS in the model list
-
click Results in the menu bar at the top of the screen
•
Results at element centres
-
select
-
Specify:
-
click the
-
Click
•
Contour map
-
Click the
-
Specify:
and
Draw and click the
icon
button; the program displays the results as shown in Figure D5a.
in the icon bar to zoom in on any part of the model (Figure D5a shows the lower-left corner).
icon.
Fill contour regions with colour
-
click the
button; the program displays the results as shown in Figure D.5b.
•
Results along a line
-
Click the
-
Specify:
-
click the
Define a section line
-
click the
Parallel to X1
-
Move the to any point on the first interior horizontal line, i.e. so that X2=7 is displayed in the bottom dialog
box. Click the mouse.
-
Define additional section lines or click the
-
click the
icon.
button; define the horizontal section line shown in Figure D.5c.
button
End
button
button; the program draws moment diagrams along the sections as shown in Figure D.5c.
To select the next Demo model –
-
click File in the top menu bar
-
select STRAP model list in the pull-down menu.
Version 11.5
2-21
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STRAP
2.6
Demo 6 - Result Combinations
For the plane frame defined in Demo 1 and Demo 3, display results for beams.
The example will demonstrate the use of the Combinations options to create a series of combinations
1.2D+1.2W+1.2L (BS8110), each combining the wind load case with one of the staggered load cases.
Please note the following:
•
In STRAP, unlike some other programs, you do not have to define the combinations along with the basic
loading cases. You can define them after the solution and change them as you like without solving the model
again.
•
STRAP also has an option to define a “group” of load cases. If a group is added to a combination definition,
the program will either:
- automatically generate a different combination for each load in the group.
- add the sum of the load cases in the group to the combination.
Using this feature when applicable can reduce the work required to create large numbers of loading
combinations.
•
Main Menu
Define the group:
-
highlight DEMO 6 - plane frame - Results in the model list
-
click Results in the menu bar
•
Combinations
-
click Combinations in the menu bar
-
click Define/revise groups in the pull-down menu
-
click the
-
Click the first -UNDEFINED- group in the list, type in a group name and click the
Add/revise a group
button
button
Click each of the Staggered load no. n so
that YES is displayed on the right-hand
side of the table opposite these cases.
click the
-
click the
Generate a combination for each load in the group
-
click the
End
Version 11.5
button
button
button
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STRAP
Define the combinations:
-
click Combinations in the menu bar
-
click Define/Revise combinations in the pull-down menu
-
in the following menu: move the to column "9:wind" for combination no.1 (first row), click the mouse and
type 1.2. Press [Enter]; the crosshair moves into the adjacent column "group 1"; type 1.2.
-
click anywhere else in the menu; the program creates the title "9*1.2+g1 *1.2" in the title column.
-
click the
button. The program generates ‘n’ load combinations, where ‘n’ = the number of staggered
load cases defined.
•
Tabular results
-
Specify
-
Specify
-
click the
button; the program displays a table showing the moment, shear and axial force at both
beam ends as well as the maximum span result.
-
Click Exit in the menu bar of the table window to return to the main menu
•
Graphic results
-
Specify
-
Specify:
and
Tables and click the
icon
Sort results by elements/nodes
Beam results: End and max. in span
Draw and click the
icon
Combination; select any combination from the pull-down list box
-
click the
•
Graphic results - Single beam
-
Display all envelope results for the beams on the first floor:
Version 11.5
button; the program superimposes the result diagram on the model geometry.
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STRAP
-
Specify
-
Specify:
Single beam and click the
icon
Select result types
Select Display a line of beams
click the
-
button.
move the adjacent to beam 5 (start of line) so that it is highlighted with a ; click the mouse. Similarly
select beam 8 (end of line); the program draws envelope diagrams for all result types for the selected line
of beam.
To select the next Demo model –
-
click File in the top menu bar
-
select STRAP model list in the pull-down menu.
Version 11.5
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STRAP
2.7
Demo 7 - Structural steel design
The model geometry as defined in STRAP does not provide sufficient information for the postprocessor to carry
out an accurate design.
For example, Figure D.7b shows a typical steel frame elevation. Figure D.7a shows the same frame as
analyzed in STRAP. It is obvious that the postprocessor is unable to determine which STRAP members form
continuous beams (chains of members must be designed as a single unit by the Postprocessor), the location
of intermediate supports for lateral-torsional buckling and axial buckling as well as design constraints.
Figure D7 - Steel Postprocessor - Design Example
Define the following design data:
•
Sections:
- beams
- columns
- bracing
Limit selection to:
- UB shapes
- UC shapes
- double angles
•
Identical beams:
- Column 11-12-13
- Column 15-16-17-18
- Column 19-20-22
- Bracing 23 and 24
specified as an identical group
specified as an identical group
specified as an identical group
specified as an identical group
•
Intermediate supports:
Members 4,7,8: "Continuous" support for +z major axis bending, major and minor axis buckling. The support
is provided by the floor slab.
•
Combined beams:
Members 11,12: Beam 3 provides buckling support only for the major axis of this column, i.e. members
11 and 12 act as a single unit for minor axis buckling. Define major axis buckling and
-z bending supports at the common node.
Version 11.5
2-25
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STRAP
Define the model:
•
Main Menu
-
highlight Demo 7 - steel postprocessor in the model list
-
click Design in the menu bar at the top of the screen
-
click Steel postprocessor in the pull-down menu
•
General
-
specify the
-
Note the default parameters listed at the bottom of the screen. They automatically apply to all members in
the model.
-
To change the default parameters, click the
-
To define different parameters for a specific member, click the
•
Section types
British section table (the first time that the postprocessor is run on the model)
icon.
icon.
The program can select the lightest section from a list (type or group) or check a specified section.
-
Click the
icon in the side menu
-
Specify
-
Click
-
Select Display in the menu bar and Section type/group/check in the pulldown menu; UB is displayed
adjacent to every beam.
-
Click the
-
Specify
-
Set
-
Click the
-
Click the
-
Select the two diagonal bracing members.
•
Identical
-
Click the
-
Click the
-
Specify
-
Create a window about the lower end of all the columns. Note that each column forms a separate “identical”
group
Limit section to section type and select UB; click the
button
Select all beams
icon in the side menu
Limit section to section type and select UC; click the
Select only beams parallel to a beam, click
Version 11.5
Select all beams
button
and select any column member
icon and select 2L in the listbox; Click
Individual beams
button
icon in the side menu
Define lines of identical beams
button
One node in the window/polygon and click the
2-26
Select by window
button
12/04
STRAP
-
Click the
-
Click the
Select a series of identical beams
-
Click the
Individual beams
•
Supports
-
Click the
-
Specify the following supports:
-
Click the
-
Click the
Individual beams
-
Click the
End
•
Combined beams
-
Combine members 11 and 12 to form a single design unit and specify the major axis support provided by
beam 3.
-
Click the
-
Specify the following supports at the common nodes:
-
Click the
-
Select beams 11 and 12: click on beam 11, click on beam 12 and then click on beam 12 again to end the
selection.
•
Compute
-
click the
icon and click the
button; the program now selects the lightest section according to
the user defined parameters. All load combination are checked for axial, bending, shear, LTB and combined
stress capacity and for slenderness and deflection limitations.
-
The program displays a table showing for each member the section selected, the critical combination, the
slenderness, deflection and the capacity ratios (actual/capacity) for each of the design checks.
-
click Exit in the menu bar.
Version 11.5
icon
button
button and select the two diagonal members.
icon in the side menu
Continuous support
button
button and select beams 4, 7, and 8.
button
icon in the side menu
Select each beams individually
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STRAP
•
Graphic results
-
click Results in the menu bar.
-
click Display selected sections in the menu bar. The program superimposes the names of the selected
sections on the model geometry.
-
click Results in the menu bar.
-
click Display capacity in the menu bar.
-
specify
-
click the Result type box and select Axial force+moment from the list displayed (or any other type).
-
click the
button; the program superimposes the capacity percentage on the model geometry. Note
the colour coding of the members and the text.
Colour by capacity and
Display % of capacity
To select the next Demo model –
-
click File in the top menu bar
-
select STRAP model list in the pull-down menu.
Version 11.5
2-28
12/04
STRAP
2.8
Demo 8 - Reinforced concrete design
Design the beams and columns of the frame shown in Figure D.8 and create a column schedule.
Figure D.8 - Concrete Postprocessor - Design Example
Beams and columns are designed separately; each has its own default parameters. The continuous beams
and columns must be defined by the user
•
Main Menu
-
highlight Demo 8 - concrete postprocessor in the model list
-
click Design in the menu bar at the top of the screen
-
click Concrete postprocessor in the pulldown menu
Note:
-
Note the Height axis = X2 parameter. The program assumes by default that all members parallel to this
axis are columns and that all members perpendicular to this axis are beams.
-
beam default parameters are listed at the bottom of the screen. They automatically apply to all beams in
the model. If you specify
columns in the side menu, different parameters will be displayed.
To change the default parameters, click the
icon.
To define different parameters for a specific member, click the
icon.
Beams
Beams in the side menu
-
Specify
•
Parameters
-
click the
-
Specify Shear reinforcement as:
Links only
Diameter: Min=8 Max=8
Shear reduction
-
click the
Version 11.5
button and the
tab
button
2-29
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STRAP
•
Define
Define the continuous beams in the model. The program assumes that beams are perpendicular to the
“Height axis” and can create them automatically.
-
Click the
icon
-
click the
-
click the
-
move the adjacent to any beam so that the beam is highlighted with a
displays the continuous beam schematically.
-
click the
-
display more beams or click the
•
Compute
-
Click the
-
Specify
For all defined beams and click the
button. The program calculates moment and shear
reinforcement for all of the beams and displays a summary table listing the results.
-
click Exit in the table menu bar
•
Results
-
select Results in the menu bar at the top of the screen
-
select Display detailed results in the pull-down menu
-
move the
-
Specify
-
The program displays the detailed results for the beam. Scroll though them.
-
click Exit in the table menu bar
Automatic definition of all beams
Display/revise beams
End
button.
button.
; click the mouse. The program
button.
End
button.
icon
adjacent to any beam so that the beam is highlighted with a
Display envelope only and click the
; click the mouse.
button.
Columns
Columns in the side menu
-
Specify
•
Default parameters
-
Click the
-
Specify
-
Click the
Version 11.5
icon
tab
2-30
12/04
STRAP
-
Specify the column lap and link details
-
click the
•
Define
button.
Define the continuous columns in the model. The program assumes that columns are parallel to the “Height
axis” and can create them automatically.
-
Click the
-
click the
-
click the
-
move the adjacent to any column so that the column is highlighted with a
displays the continuous column schematically.
-
click the
-
display more columns or click the
•
Compute
-
Click the
-
Specify For all defined columns and click the
button. The program calculates reinforcement for
all of the columns and displays a summary table listing the results.
-
click Exit in the table menu bar
•
Results
-
select Results in the menu bar at the top of the screen
-
select Display detailed results in the pull-down menu
-
move the
-
Specify
-
The program displays the detailed results for the column. Scroll though them.
-
click Exit in the table menu bar
•
Column schedule
-
Click the
-
click the
-
type in the table name, select the table size and orientation.
-
Click
Edit
-
click
Select all beams
Version 11.5
icon
Automatic definition of all columns
Display/revise columns
End
button.
button.
; click the mouse. The program
button.
End
button.
icon
adjacent to any column so that the beam is highlighted with a
Design combination only and click the
; click the mouse.
button.
icon
New table
button.
to include all columns in the table
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12/04
STRAP
-
specify the schedule format parameters:
-
click the
button to display the schedule.
The schedule is displayed without the elevations and with diamond-shaped additional links. Let’s add the
elevation for column 4 and revise the links to rectangular ones.
-
Click the
icon.
-
Click and highlight COL 4 in the table and click the
a new line is added to the table.
-
click the
-
Click the
icon.
-
Click the
icon.
-
Click the
-
click
-
click the
-
Click
Add elevation
button on the right of the dialog box;
button to display the schedule again with the elevation for column 4.
Link types
Select all beams
End
Edit
Use rectangular links where possible
button and select
to revise all the columns in the model
button and click the
icon
To display the revised schedule.
To select the next Demo model –
-
click File in the top menu bar
-
select STRAP model list in the pull-down menu.
Version 11.5
2-32
12/04
STRAP
2.9
Demo 9 - Light gauge steel design
Figure D9 - Light Gauge Steel Design
This demo demonstrates the definition and design of a structure fabricated from Cold-formed (light gauge) steel
sections.
The program designs cold formed sections according to one of the following codes:
•
•
AISI ASD or LRFD specification - 1996.
AISI ASD specification - 1986 with the 1989 addendum.
The user may use the standard section tables included in the program or define his own sections.
Note that structures with both cold-formed and hot-rolled sections may be designed by the program.
The following design data will be defined in the demo:
Sections:
- truss members :
- Columns
:
limit sections to C+Lips
limit sections to CDEE
Identical beams:
- Members 23-24 specified as an identical group.
- Members 7-8-9-10-11-12-21-22 specified as an identical group.
- Members 1-2-3-4-5-6 specified as identical group.
Intermediate supports:
Members 7-8-9-10-11-12:
Members 23-24:
Combined beams:
Members 1-2-3; 4-5-6:
Version 11.5
support for +Z major axis bending ,
minor axis buckling.
support for +Z major axis bending.
minor axis buckling.
Define major axis buckling at the common nodes.
2-33
12/04
STRAP
Define the model:
•
Sections
-
Select Files in the menu bar of the STRAP models list.
-
Move the
-
Select File in the menu at the top of the screen.
-
Select Edit cold form table file.
-
Select Edit in the menu bar at the top of the screen.
-
Select Add section type in the pull down menu.
-
Click the
-
Select: 2C sections with lips front to front
-
Type the Section type name as - DCEE (notice that DCEE in the section type menu is highlighted).
-
Click the
-
Select Edit in the menu bar and Select Add section to current type.
to Utilities and select Create/Edit a steel section table.
button to open the section shape pull-down-menu
button
Enter the dimensions
Click the
button
-
Click
in the section data table
-
Click File in the menu bar
-
Click Exit in the file menu.
•
Main Menu
-
Highlight Demo 9 - Cold Formed in the model list.
-
Click Design in the menu bar at the top of the screen.
-
Click Steel postprocessor in the pull-down menu.
•
Default parameters
-
Note the current default parameters listed at the bottom of the screen. To change a parameter, click the
icon in the side menu
Version 11.5
2-34
12/04
STRAP
-
specify a new value for Fy:
Click the Steel grade tab
select “User defined” in the “Steel grade” list
box and type “50” in the adjacent “Fy=“ text
box.
-
Click
•
Sections
-
Click the
-
Specify
Limit section to section type and select C+Lips; click the
-
Specify
both nodes in the Window/polygon and click
-
Create a window about the truss.
-
Click the
-
Click the
-
Select the two column members.
icon in the side menu
button
Select by window
icon and select DCEE section type; Click
Individual beams
button
To display and check the last definition:
-
Click Display in the menu bar at the top of the screen
-
Click Section Type/Group/Check in the pull-down menu
-
(To Delete the section type from the display use the same option again)
•
Identical
-
Click the
-
Click the
Select a series of identical beams
-
Click the
Individual beams
-
Click the
-
Click the
-
Click the
icon in the side menu
button
button and select the two columns (members 23,24)
icon
Define lines of identical beams
Individual beams
button
button and select the beam members 21,22 and 1.
Note that each beam forms a separate identical group. (use “Display” option)
Version 11.5
2-35
12/04
STRAP
•
Supports
-
Click the
-
Specify the following supports:
-
Click the
-
Click the
-
Specify Distance from beam start = 4.5
-
Click the
-
Click the
-
Specify the following supports:
-
Click the
-
Click the
-
Specify Distance from beam start = 3.0
-
Click the
-
Specify Distance from beam start = 6.0
-
Click the
Next support
button
Specify Distance from beam start = 9.0
-
Click the
Next support
-
Click the
End
-
Use the “Display” option to check your definition
•
Combined beams
icon in the side menu
Intermediate supports
Individual beams
End
button
button and select the beams 7-8-9-10-11-12.
button
icon
Intermediate supports
Individual beams
Next support
button
button and select the columns 23, 24.
button
button
button
Combine members 1-2-3 and 4-5-6 to form a single design unit:
-
Click the
-
Specify the following supports at the common nodes:
Version 11.5
icon in the side menu
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12/04
STRAP
Select start and end beams in a line
-
Click the
-
Select beams 1 and 3
-
Click the
-
Specify the following supports at the common nodes:
-
Click the
-
Select beams 4 and 6.
-
Use the “Display” option to check your definition.
•
Compute
-
Click the
-
Click the
button; the program now selects the lightest section according to the user defined
parameters and slenderness and deflection limitations.
-
The program displays a table showing for each member the section selected, the critical combination, the
slenderness, deflection and the capacity ratios (actual/capacity) for each of the design checks.
-
Click Exit in the table menu bar.
•
Results
-
Select Results in the menu bar
-
Select Display detailed results in the pull-down menu.
-
Move the
-
Specify
-
The program displays the detailed results for the column. Scroll through them.
-
click Exit in the menu bar.
icon in the side menu
Select start and end beams in a line
icon in the side menu
adjacent to column 23 so that the column is highlighted with a
Design combination only and click the
; click the mouse.
button
To select the next Demo model -
Click File in the top menu bar.
-
Select STRAP model list in the pull-down menu.
Version 11.5
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STRAP
2.10
Demo 10 - Bridge loading analysis
The bridge module automatically calculates the critical loading pattern that generates the max/minresults for
any result type at any point on the bridge.
Analyze the bridge shown in Figure D10.1
Figure D10.1 - Bridge example, Lanes
•
General
-
Divide the bridge into lanes and then divide each lane into strips perpendicular to the axis of the lane.
-
Solve the model: the program automatically applies a unit load to each strip in a separate load case (no. of
load cases = no. of strips). The program uses the results of those cases to calculate worst case effects by
means of superposition.
-
Define lane loads: specify the vehicle loads and the distributed loads required by the codes on each of the
lanes.
-
Create load cases: tell the program how to arrange the various lane loads to create the design load cases.
-
Transfer results to STRAP: append a load case to the STRAP results files that contains an envelope of the
maximum results for vehicle load.
-
Create combinations of the vehicle results and the self-weight and temperature loads.
•
Main Menu
-
Highlight Demo10 – Two lanes bridge in the model list.
-
Click Design in the menu bar and Bridge module in the pull-down menu.
•
Lanes
-
The bridge consists of 2 parallel lanes, each 9 feet wide. They are defined by specifying the center line axis
and width.
Select Lanes
-
Click the
-
Click Node 5 to specify the start of lane.
-
Click Node 8 to specify the end of lane.
Version 11.5
icon to define lane 1.
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STRAP
-
Define the lane parameters:
Type in lane Width and the center line Offset (the
offset of the lane center from the line connecting
start and end nodes)
Type in the number of strips
Click End definition
-
Similarly define lane 2 between nodes 13 and 16.
•
Load distribution
The generated loads may be applied to nodes, elements or selected beams.
-
Select Options in the menu bar.
-
Select Load direction to specify the Global direction of applied loads.
-
Select Global X3 direction
Select Options in the menu bar.
-
Select Loads distribution in the pull down menu.
Click All beams
Click the
•
button
Solve the model
STRAP will create one case for each strip in the model (a unit load is applied to the strip), i.e. 240 load
cases will be solved in this model.
-
Demo version:
The large number of load cases exceeds the limit of the Demo version. To continue, please go to Demo
11 which is identical to this model but includes the result files.
-
Regular version:
Select File in the menu bar and Solve in the pulldown menu and then continue according to the
instructions in Demo 11.
Version 11.5
2-39
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STRAP
2.11
Demo 11 - Bridge analysis – Results
•
Main Menu
-
Highlight Demo 11 – Two lanes bridge – Results.
-
Click Design in the menu bar and Bridge model in the pull down menu.
•
Display influence lines
Display influence lines for any STRAP beam ,element or node for any result type. For example, display the
influence line for M2 moment at the center of beam 111.
-
Select Results in the menu bar:
Select Draw influence lines
Select Beam results
Select M2
At the midpoint of the span
Click the
-
To select beam 111, highlight it with the
-
The program displays the following influence line:
Version 11.5
button
and click the left button of the mouse.
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STRAP
•
Define lane loads
-
Specify the vehicle loads applied to the lanes. The following lane loads may be defined: uniform, vehicle,
knife-edge loads.
Select Lane load
-
Click the
icon
Type in Load case name
Type in Uniform load
Select a load reduction (vs. length) factor
table
Select a Vehicle group
Type in Knife edge load value(applied by
the program as a uniform load to a strip)
Click the
•
button
Define load cases
Assign a lane load to each lane to define a load case. The program applies the load to each of the strips along
the length of the lanes; only those loads that contribute to the requested maximum/minimum result are used.
Select load cases
Version 11.5
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-
Click the
icon
-
Define three load cases:
1 - apply lane load A to lane 1 only.
2 - apply lane load A to lane 2 only.
3 - apply lane load A to both lane 1 and lane 2.
-
Define load case 1 and 2:
Create the load cases by specifying all possible permutations of the lane loads on the selected lanes. The
program will create load cases by interchanging the lane loads.
Select lane load A
Select lane 1
Specify all possible permutations
on lanes 1 and 2
Click the Assign button
Click the
-
button
Define load case no. 3.
Select lane load A
Select lane 1 and 2
Click the Assign button
Click the
•
button
Display selected results
The program displays the loads applied to the various strips that are required to generate the
maximum/minimum result. For example, display the maximum absolute value for Mx result in the center
of element 58.
-
Select Results in the menu bar.
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Select Draw applied loads for selected results
Select Absolute value maximum
Click the
button
Select Element results
Select Result type and Location
Click the
button
-
To select element 58 click the mouse.
-
The program displays the location of the loads applied to achieve the max results.
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•
Transfer results to STRAP
Create a single STRAP load case consisting of a maximum result envelope for all results types (moment,
shear, etc.). Note that you can create separate load cases for each result type.
The program will search for the critical load pattern for each result type for each node, element and beam
(1/10th of span). The results will be transferred to the STRAP results file.
-
Select Results in the menu bar.
-
select Update STRAP result file.
Select envelope result type
Type in name
Click the
button
The program runs about one MILLION comparisons for each beam in this model for computing the envelope
and takes a few minutes to complete the calculation.
-
Select File in the menu bar.
-
Select STRAP results to return to the STRAP results screen.
•
Combinations
The model also contains other load types e.g. self-weight and temperature (already defined). Let's now
define factored loading combinations of these loads with the vehicle loads envelope.
-
Select Combinations in the menu bar
Define/revise combinations
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-
Click the
button to exit from table.
-
To display results:
click Draw
click the
icon
Select Display type
Select Result type
Select Load combination
Select Fill contour regions with color
Click the
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2.12
Space Frame with Wall Elements
Define the geometry of the following 10-storey building that includes four walls extending the full height of the
structure:
Note:
• this example explains how to define the geometry; for dynamic analysis and interpretation of the results,
refer to
• The model is used for dynamic analysis only:
- the slabs are defined with dummy elements; the in-plane rigidity is provided by rigid links.
- columns are not defined because their contribution to the lateral stiffness is negligible.
To define the model:
•
Main Menu
-
Double-click DEMO-Empty model in the model list.
•
Preliminary Menu
-
Set the Model Type to
-
click the
•
Geometry
Space frame
button
Define the wall reference nodes 1, 2, 3, 4 at ground level (X3=0.0):
-
click the
icon
-
click the
icon
-
Node 1: Move the crosshair to X1 = 0.0, X2 = 8.0, X3 = 0.0 and click the mouse.
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Node 2: Move the crosshair to X1 = 24.0, X2 = 20.0, X3 = 0.0 and click the mouse.
-
Node 3: Move the crosshair to X1 = 24.0, X2 =
-
Node 4: Move the crosshair to X1 = 9.15, X2 = 13.85, X3 = 0.0 and click the mouse.
-
Click End definition
0.0, X3 = 0.0 and click the mouse.
Define the supports:
-
Click the
icon.
-
Click the
icon.
-
Click the
icon.
-
Click the
Select all nodes
button
Copy the nodes to all 10 floors:
-
Click the
icon
-
Click the
icon
- Click the
icon in the Copy options menu at the side of the screen
Select all nodes
-
Click the
-
select any of the 4 nodes as the reference node
-
Click the
-
Define the floor levels at 3.0 m intervals (X3): Press the left mouse button and do not release; move the
into the X3 edit box (note that the coordinates will not change) and type 3.0:
-
set Number of copies: 10 and click
-
click the Isometric View icon
by coordinates
button
button
in the icon bar to display the entire model.
Define the wall sections:
-
Click the
icon
-
Click the
icon
- Click the
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Select the section:
Select section 1
Click Edit/add section
-
Define the properties and dimensions of Wall 1; the wall consists of one segment only and we will define
the segment end at DX=0, DY=400:
Specify thickness = 300
Specify DY = 4000mm
and press [Enter]
The segment is drawn in the
center box as
Click Close
Define Wall 2 section:
- Click the
icon in the menu at the side of the screen
-
Highlight section no . 2 and click Edit/add section
-
The wall is composed of two segments; the first ends at DX=4000; DY=0. Set the Thickness = 300, type
in DX = 4000 and press [Enter]; the first segment is drawn in the center box:
-
the second segment is offset DX=0, DY=3000 from the end of the first segment. The cursor is already in
the DY= box; type 3000 and press [Enter]; the second segment is added to the display:
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Note the “reference point” at the first corner denoted by the .
This is the point where the wall section will be attached to nodes
in the structural model. Referring to the floor plan at the
beginning of this example, it is apparent that Walls 2a/2b will be
attached at the corner joining the two segments in the section.
To move the reference point, click
; move the
to the new location so that it is highlighted with the ; click the
mouse. The
will now appear at the correct location.
-
Click Close
Define Wall 3 section:
-
Wall 3 is created by defining nine segments in the following order:
Note:
- segments 3 and 5 are coupling beams
- segment 9 bisects segments 4 and 8 and
divides them each into two new
segments.
- Click the
icon in the menu at the side of the screen
-
Highlight section no . 3 and click Edit/add section
-
Segment 1:
Specify thickness = 300
Specify DY = -2000mm
and press [Enter]
The segment is drawn in the center box:
-
Segment 2:
Specify DX = 1000mm and press [Enter]. The segment is drawn:
-
Segment 3 (coupling beam):
Specify
Coupling beam
H= 800 mm
Specify DX = 1000mm
and press [Enter]
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Segment 4:
Specify
Wall and DX = 2000
-
Segment 5:
Specify
Coupling beam and DX = 1000
-
Segment 6:
Specify
Wall and DX = 1000
-
Segment 7:
Specify
Wall and DY = 2000
-
Segment 8:
This segment ends at the start of segment 1
-
Specify
Another segment end
Click Select segment end
move the
-
to the start of Segment 1 so that it is highlighted with the
; click the mouse.
Segment 9:
Specify Thickness = 600 mm
This segment starts at the mid-point of segment 4 and ends at the mid-point of segment 8
Click Within a segment
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move the
adjacent to segment 4 so that it is
highlighted with the ; click the mouse.
Specify the location along segment 4:
Enter the distance from the start of the segment to the
mid-point.
Now define the end-point of the segment:
Specify
Within another segment
Click Select segment end
Move the adjacent to segment 8 so that it is highlighted with the ; click the mouse. Specify the location
of the end point of segment 9 at the mid-point of section 8, as explained above for the start point.
-
Section 3 is now complete; Click Close.
Now we will attach the three wall sections to the model:
-
click the node number icon
numbers to the display:
-
click
-
select the wall section:
-
attach section 1 to line 1-41:
move the
in the icon bar to add the node
adjacent to node 1 so that it is highlighted with the
; click the mouse; move the adjacent to node 41 so that it
is highlighted with the ; click the mouse;
The program adds the wall section to the line 1-41.
-
attach section 2 to line 2-42:
Specify Sect =2 and select nodes 2 and 42. Note that the
orientation of the wall is not correct. We will rotate it after the
other three walls have been attached.
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-
attach section 2 to line 3-43:
Specify Sect =2 and select nodes 3 and 43
-
attach section 3 to line 4-44:
Specify Sect =3 and select nodes 4 and 44
-
click the node number icon
, the Isometric View icon
displayed on theX1-X2 without numbering or restraints:
and the Restraints icon
. The model is
All of the walls are oriented correctly except Wall2a (check the
coordinates of the wall corners by clicking on the
Data icon )
-
Rotate Wall 2a:
click the Isometric View icon
-
click
-
the wall may be flipped or rotated:
icon
Specify
Flip about X axis
-
Click Select by window
-
Create a window around Wall 2a; the program flips it into its correct position.
Define the floor slabs:
The floor slabs are modeled by dummy elements since the model will be solved only for dynamic loads. The
elements are necessary in order to define the masses, but the size of the elements is not important.
We will define the slab at X3=3.00 and copy it to the other 10 levels.
-
Click on Remove in the toolbar at the top of the screen
-
Select Limit display to a plane
-
Select any three nodes at X3 = +3.00
-
click the Isometric View icon
to display theX1-X2 plane
Define the nodes at the X1=0 corners of the slab
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-
click the
icon
-
click the
icon
-
Type in the coordinates X1 = 0.0, X2 = 0.0, X3 = 3.0 in the dialog box at the bottom of the screen
-
Type in the coordinates X1 = 0.0, X2 = 20.0, X3 = 3.0 in the dialog box
Define the element mesh:
-
click the
icon
-
click the
icon
Click OK
-
Select the four corner nodes and end the selection by clicking the first corner again
Select End contour definition
Specify Grid steps: X = 2.4, Y=2.0 and click OK
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-
click
in the Elements menu
-
click Dummy element
-
Select meshes
-
select any two nodes in the mesh
-
Click on Remove in the toolbar at the top of the screen
-
Select Limit display to a plane
Cancel last plane selection
-
click the Isometric View icon
Copy the slab to the other nine levels:
-
Click the
icon in the main menu.
-
Click the
icon in the copy options menu
-
Click the
By levels
-
Select level X3 as the height axis; select X3 = +3.00 and click
-
Select a reference mode: move the
with a ; click the mouse.
Version 11.5
button
adjacent to the node in the left corner so that the node is highlighted
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-
Define the new location of the reference node:
-
Click the
-
Click and hold the left mouse button and drag the cursor into the dialog box at the bottom of the screen the coordinate values in the box will not change as the cursor moves. Type the coordinates X3=6.0.
-
specify No. of copies = 9
-
Click
by coordinates
button
to continue
Define Rigid links in the slab plane:
-
Rotate the model so that it is displayed on the X1-X3 plane. Select Rotate in the toolbar, specify X1-X2 and
enter the rotation values X1 = -90, Y = 0, Z = 0
-
Click the
icon in the main menu.
-
Click the
icon in the Restraints options menu
Select X1-X2 plane
Select Selected nodes with same X3 coordinates
-
Select the nodes in the entire model, except the support nodes at X3=0.0
The geometry of the model is now complete. Refer to the next example for the dynamic analysis of this model.
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2.13
Wall elements - dynamic analysis
This example is a continuation of Example 2.12. The files for this model contain the geometry as defined as
well as the following static loads applied to all floor slabs on all levels:
- Dead = 8.0 kN/m2
- Live = 1.5 kN/m2
The mass used for the dynamic analysis will be based on these static loads.
Main Menu:
-
highlight DEMO 13 - WALLS - DYNAMIC in the model list
-
click on Dynamics in the toolbar and Weight data in the pulldown menu.
-
click the
icon
-
click the
icon
-
Select File in the toolbar and Solve the model in the pulldown menu.
-
Select Seismic analysis in the tool bar and Method for combining modes in the pulldown menu
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-
Select Seismic analysis in the tool bar and Parameters in the pulldown menu
(If UBC is not displayed in the title of the
box, click Select another code and select
UBC 1997)
-
click the Tables -
icon
The results for all wall segments are displayed on the screen.
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Add the dynamic results to the static results file:
-
Select Seismic analysis in the toolbar and Update static results files in the pulldown menu
Display the results in STRAP:
-
Select File in the toolbar and Static results in the pulldown menu
-
click the Graphics -
icon
The moments in the walls are displayed.
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3 Miscellaneous
3.1
Defining new models
New models with up to 12 nodes may be defined, saved and solved.
-
select Files in the menu bar
-
select New model in the pull-down menu.
-
Revise model title if necessary:
-
arrange the preliminary geometry menu:
Select the default units
Enter the model title
click Continue to proceed to geometry
Select the model type
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3.2
How to Use HELP
The windows version of STRAP provides the user with extensive on-line Help; the entire User's Manual is an
integral part of the program and may be displayed at any time.
STRAP Help uses the standard Windows Help format; a window containing the Help is displayed on the right
half of the screen.
There are two ways to call Help while running the program:
•
press the
•
click the Help option in the menu bar at the top of the screen and select Contents in the pull-down
menu: The Table of Contents of the full STRAP User's Manual is then displayed; select any topic in the list.
Version 11.5
key: Help for the current option will be displayed.
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