Define a tendon profile along the length of elements. Create the tendon
profile relative to its own coordinate system, which will then be inserted
relative to the elements.
Note
1
Tendon placement can be simplified by copying, rotating and sloping tendon
profiles.
Note
2
Tendon properties can be changed at the Tendon Profile location in Works
Tree.
From the Main Menu
select Load > Prestress
Loads > Tendon Profile.
Select Static Loads
> Prestress Loads > Tendon Profile in the Menu
tab of the Tree
Menu.
Tendon Profile dialog box
Note
If a Tendon Profile is selected from the Tendon Profile List, the tendon
placement is displayed on the screen.
Click in
the Tendon Profile dialog box to enter new tendon placement. Click to change and to eliminate a previously defined
profile.
: Tendon properties
assigned to a number of Tendon Profiles can be changed at the same time.
Note
If there are a number of Profiles, which are required to have Tendon Properties
changed, this functionality allows us to change them simultaneously, rather
than changing them one by one in each profile.
Change
Tendon Property dialog box
Click on the button to Copy
or Move the inputted Tendon Profile
Copy/Move
Tendon Profile Dialog box
Mode
Copy:
Copy the selected Tendon Profile
Move:
Move the selected Tendon Profile
Translation
Select one of the following options to Copy/Move
the selected Tendon Profile
Element
Increment: Copy/Move the selected Tendon Profile as per the inputted
increment of element number. To Copy/Move the tendon profile defined with
this option, at 1, 3, 5, 7 (G1), the following conditions should be satisfied.
?The increment of each
corresponding element should be identical
For example, Tendon Profile entered in element
1, 3, 5, 7 (G1) can be Copied/Moved to element 51, 53, 55, 57 (G2) because
the increment is identical. On the other hand, the Tendon Profile cannot
be Copied/Moved to 11, 12, 13, 14 (G3) because the increment is different
for each element.
?The number of elements
to Copy/Move should be the same
For example, the Tendon Profile entered in
element 1, 3, 5, 7 (G1) can be Copied/Moved to G4 which has the same number
of elements. On the other hand, Tendon Profile cannot be Copied/Moved
to G5 since the number of elements is different.
As displayed the figure below, the length
of each element does not matter while performing the Copy/Move commands.
Element
Increment Option
Note
1. Element Increment option can be selected only when the Tendon Profile
is defined.
2. Element Increment option is a change of element that is included in
Assigned Elements and Insertion Point.
Equal Distance
Enter the absolute distance to Copy/Move
the Tendon profile to a particular location. While using this option,
the following conditions should be satisfied.
?At the distance inputted to Copy/Move the
Tendon Profile from the initial Insertion Point of the original element,
a node of the element where the Tendon Profile is to be Copied/Moved must
exist. This node will define the new Insertion Point. If this node does
not exist, then an error message will be displayed.
?If there is more than one element attached
to the initial element, then the Tendon Profile will be assigned to the
attached element that is most linear.
?If Straight/Curve type Tendon Profile is
to be Copied/Moved, then the original length and number of elements should
be equal to the length and number of elements at the new location.
New Assigned
Element: Input new Assigned Elements and Insertion Point to Copy/Move
a Tendon Profile to those elements.
Auto-Adjustment of Tendon Length
If a Tendon Profile is Copied/Moved to an
element whose total length is different from the total length of the original
element, then checking this option will automatically adjust the tendon
length based on the ratio of the original element length to the length
of the element where the Tendon Profile is copied.
Move
Move the previously defined tendon layout.
Tendon Profile Definition dialog box
Tendon Name
Note
1
Name assigned within 20 alphanumeric characters
Group
Define Tendon Groups. Once Tendon Groups
are defined, coordinates, stresses and prestress losses of tendons can
be checked by Tendon Groups. Click to the right to add new,
modify or delete previously defined Tendon Groups. Tendon Groups can be
assigned to the tendons having the same tendon property.
Tendon Property
Define the tendon properties. Click to the right to add new, modify or delete previously defined
tendon properties.
Assigned Elements
Specify the element numbers to which the
tendon will be assigned.
Use the Graphical Selection function of MIDAS/Gen
to automatically specify the numbers by selecting the elements on the
screen.
Input Type
The dimension of Tendon Profile is specified.
2-D
Tendon Profile is defined in 2-dimensional coordinates.
3-D
Tendon Profile is defined in 3-dimensional coordinates.
Curve Type
Specify the type of curvature for tendon
placement.
Spline
Calculate the minimum polynomial curvature connecting the points defining
the tendon profile and auto-place the tendons
Round
Place the tendons following the circle, which forms tangents to the straight
lines connecting the points defining the tendon profile.
Straight Length of Tendon
Specify the straight portions of the tendon
at both ends.
Begin:
at the beginning of the tendon
End: at the end of the tendon
Typical Tendon
This is a function for defining a lumped
representative tendon. If this option is checked on and the number of
tendons is inputted, the generated tendon profile is multiplied by the
inputted number of tendons when analysis is performed. For simple analysis,
such as the schematic design of a bridge, inputting 3 dimensional tendon
profiles is time consuming. Therefore, using the function of lumped representative
tendon, which defines only one tendon profile for analysis, the time required
for generating the model and performing analysis can be reduced.
After analysis is performed, the results
for only one tendon are displayed.
Transfer Length
Enter a Transfer Length. In both pretensioned
and post-tensioned beams, compressive stress due to tendon prestressing
forces is not fully distributed to the top and bottom fibers of the member
near the end anchorage zones or beam ends over a Transfer Length.
The Transfer Length can be either input by
the user or obtained by automatic calculation. For the automatic calculation
by formula, two methods are available depending on Tendon Property (Post-tension
or Pre-tension).
User Defined
Length: Enter a Transfer Length manually.
Begin:
Beginning portion of the Transfer Length
End:
End portion of the Transfer Length
Auto Calc
(0.5x(H+Bf/n): For Post-tensioning, the transfer length is auto-calculated
as below.
L=0.5x(H+Bf/n)
where, H:
Section depth, Bf: Flange width, n: Number of webs (2 for 1Cell)
Auto Calc
(65xStrand Diameter): For Pre-tensioning, the transfer length is
auto-calculated as below.
L=65xStrand Diameter
Profile
Place the tendon profile by defining the
coordinates of the tendon. The tendon coordinate system (TCS) used here
is temporary, and its origin is the starting point of the tendon, which
will be related to the elements by the profile insertion point. As many
coordinates as required to define the profile may be specified, but at
least two (start and end) points are required. The x-axis of TCS is parallel
with a Global axis in the length direction, and the z-axis of TCS coincides
with the Global Z-axis. See Tendon Shape below for further details.
x, y, z:
tendon coordinates in TCS
fix:
check in the box to specify the tangent
to the tendon curvature at the point in question.
Ry:
if "fix" is checked, the angle of the tangent line relative
to the x-axis in the TCS x-z Plane
Rz:
if "fix" is checked, the angle of the tangent line relative
to the x-axis in the TCS x-y Plane
Note
The tendon profile is created following the geometry specifications and
maintaining the least change of curvatures.
Note
When 2-D of Input Type and Round of Curve Type are used to create the Tendon
Profile shown in the figure below, it can be simply created by using the
coordinates (x1, y1), (x2, y2) and A1, A2, h1, h2, r1, r2. When the Tendon
is to be placed to the right of the entered coordinates, select Right
in the Add column. When it is to be placed to the left of the entered
coordinates, select Left in the Add column.
Input
Tendon Profile by using 2D Round
BOT:
If BOT is checked on two points of a tendon profile, whose vertical distances
from the bottom of the section (z distance) are equal, then the vertical
distance from the bottom of the section to the tendon remains the same
between the two points.
However, if the two points where BOT is checked
have different vertical distances from the bottom of the section, then
the tendon is considered to be a straight line and its coordinates are
linearly interpolated at intermediate points.
For the following cases, BOT cannot be checked
If Spline
is selected: If the corresponding points are included in a straight
line (inputted in Straight Length of Tendon) then BOT cannot be selected.
If Round
is selected: If R is inputted on the corresponding point then BOT
cannot be selected.
Point of Sym.
First:
The starting point of the current Tendon is assumed to be the axis of
symmetry.
Last:
The end point of the current Tendon is assumed to be the axis of symmetry.
: Tendon Profile is created on the basis of the selected
symmetry point (First or Last).
Tendon Shape
Straight:
the x-direction (the reference line from which tendon coordinates are
defined) of TCS for tendon placement is considered as a straight line.
Curve:
the x-direction (the reference line from which tendon coordinates are
defined) of TCS for tendon placement is considered as a curved line.
Element:
Tendon location is converted into Element Coordinate System and applied.
Note
If Element is selected in Tendon Shape, Tendon Profile moves with Element's
movement.
1. Straight
Profile Insertion Point
The origin of the tendon coordinate system (start point of tendon) is identified
and inserted into the actual location in the global coordinate system.
x Axis Direction
In the case of a Straight Tendon Shape, define the x-axis of TCS for tendon
placement.
X:
x-axis of TCS is parallel with GCS X-axis
Y:
x-axis of TCS is parallel with GCS Y-axis
Vector: define the TCS x-direction by a Vector specified
in the entry field below.
x Axis Rot.
Angle
The tendon profile placed in the table is
rotated about TCS x-axis by the Angle. This is usefully implemented when
placing a tendon on an inclined (non-vertical)
web.
Note
x
Axis Rot. Angle must be entered between -85 and +85 degrees.
Projection
The tendon profile placed in the table is
projected on the plane, which is rotated about TCS x-axis by the Angle.
Grad. Rot.
Angle
The tendon placement is rotated about the GCS Y or Z-axis. This is a useful
feature when attempting to place the tendon along the element, which is
inclined along its local x-axis.
Note
Tendons can be placed only in beam elements. The assigned beam elements
do not necessarily have to be interconnected. We can check the Tendon
Profile in the Misc. tab of Display by checking in the
appropriate box. External tendons are assumed to retain the straight line
placing profile.
2. Curve
Profile Insertion Point
The origin of the tendon coordinate system (start point of tendon) is identified
and inserted into the actual location in the global coordinate system.
Radius Center
(X, Y)
In the case of a Curved Tendon Shape, enter the coordinates of the center
of the circle in GCS.
Offset
place the tendon at the projected location in the radial direction
Note
In the case of a Curved Tendon Shape, the tendon is placed along the circumference
of the circle defined by the radius formed by the start point of the tendon
(origin of TCS) and the center of the circle. The Offset increases or
decreases the radius by the specified magnitude while maintaining the
center of the circle. Again the tendon is placed along the changed circumference.
When several tendons are placed side by side, use the Copy function to
copy the previously entered tendon and relocate the copied tendon by Offset.
Direction
CW:
define the curve clockwise
CCW:
define the curve counter-clockwise
x Axis Rot. Angle
The tendon profile placed in the table is rotated about TCS x-axis by the
Angle. This is usefully implemented when placing a tendon on an inclined
(non-vertical) web.
Note
x
Axis Rot. Angle must be entered between -85 and +85 degrees.
Projection
The tendon profile placed in the table is projected on the plane, which
is rotated about TCS x-axis by the Angle.
Grad. Rot.
Angle
The tendon placement is rotated about the GCS Y or Z-axis. This is a useful
feature when attempting to place the tendon along the element, which is
inclined along its local x-axis.
Note
Tendons can be placed only in beam elements. The assigned beam elements
do not necessarily have to be interconnected. We can check the Tendon
Profile in the Misc. tab of Display by checking in the appropriate box. External tendons
are assumed to retain the straight line placing profile.
3. Element
Profile
Insertion Point
The origin of the tendon coordinate system (start point of tendon) is identified
and inserted into the actual location in the global coordinate system.
End-I of Elem.: I-end of the specified
Element is referenced as the insertion point.
End-J of
Elem.: J-end of the specified Element is referenced as the insertion
point.
x Axis Direction
In the case of a Straight Tendon Shape, define the x-axis of TCS for tendon
placement.
I->J
of Elem.: The x-axis in TCS is defined in the direction from the
I-end to J-end of the element.
J->I
of Elem.: The x-axis in TCS is defined in the direction from the
J-end to I-end of the element.
x Axis Rot.
Angle
The tendon profile placed in the table is rotated about TCS x-axis by the
Angle. This is usefully implemented when placing a tendon on an inclined
(non-vertical) web.
Note
x Axis Rot. Angle must be
entered between -85 and +85 degrees.
Projection
The tendon profile placed in the table is projected on the plane, which
is rotated about TCS x-axis by the Angle.
Offset:Tendon Offset is defined in the Element
Coordinate System (ECS).
y:
Distance by which the tendon profile is moved in the ECS y-axis direction
z:
Distance by which the tendon profile is moved in the ECS z-axis direction
in
the Tendon Profile dialog box to enter new tendon placement. Click 
to change and 
to eliminate a previously defined
profile.
: Tendon properties
assigned to a number of Tendon Profiles can be changed at the same time.
button to Copy
or Move the inputted Tendon Profile
Mode
to the right to add new,
modify or delete previously defined Tendon Groups. Tendon Groups can be
assigned to the tendons having the same tendon property.
: Tendon Profile is created on the basis of the selected
symmetry point (First or Last).
Display by checking in the
appropriate box. External tendons are assumed to retain the straight line
placing profile.