RAPT User Manual Copyright PCDC

Line Loads Toolbar

The default button in the loads dialogs is always OK (shows 3D or expressed). If the focus is in an edit cell, the OK
button will always accept an Enter key press without having to move the focus to it. Pressing enter while in the edit
cells will accept the data and insert the load as defined. Adding the load can be cancelled by clicking on or moving to
and pressing enter on the Cancel Button.

If using the keyboard to navigate around the dialog, use the Tab key (forwards or Shift + Tab key (backwards) to
move the focus. Using the Tab key at the end of a row will move focus to the start of the next row.

A blank cell is regarded as having a value of zero.

Add general trapezoidal load:- Will add a linearly varying load over the length nominated. The dialog below will
be presented for input of the load start and end locations and load values. Data focus is initially in the Distance from
Last Load cell. When the start load value is initially entered, the end load value will default to the same value creating
a uniformly distributed load. The designer can over-ride this default end value to create a linearly varying load. RAPT
will refuse to add the load if the load length is negative or if one of the ends is outside the frame or if the two load
values are zero.

Add multiple trapezoidal loads:- Will add multiple linearly varying loads over the lengths nominated. The
dialog below will be presented for input of the load start, load lengths and load values. Data focus is initially in the
Distance From Last Load cell. When the start load value is initially entered, the end load value will default to the same
value creating a uniformly distributed load. The designer can over-ride this default end value to create a linearly
varying load. RAPT will refuse to add the load if the load length is negative or if one of the ends is outside the frame. A
load segment can have zero loads at both ends. RAPT will insert this as a gap in the load pattern of the length defined.

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Add Concentrated load:- Most point loads actually apply load over at least the length of the item applying the
load e.g. a transverse wall has a thickness. Many design codes also allow these loads to be distributed over an even
wider area. Even though a point load is being defined, RAPT will apply it as a distributed load over the load length.
RAPT allows the designer to define a point load with a length over which the load is applied. The load will be applied
centred at the defined load location. The designer should ensure that the full extent of the load will be within the frame
length.

As well as defining a load location and a load value the designer is asked for a Load Length. This length cannot be
zero. If a knife-edge load is required (zero load length), input it under the 7.2.4.1.1.4 Point Load input.

Add Number of Loads:- RAPT will allow the user to define a number of loads and create the space for these
loads in the data grid. No load values will be input by RAPT. The designer must add all load data for these loads. This
has been done to allow designers to copy loads from another data source (either another loads grid in RAPT or from an
external spreadsheet) into the RAPT data fields.

Delete load:- Deletes the selected loads. The loads must be selected by clicking on the load number cell. Multiple
loads and non-continuous groups of loads can be selected using the 4.4.3 Cell Selection rules.

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Copy:- Copy a selected group of loads to memory for later Paste operation. The Copy option will only be available
after a legal selection is made. Any loads in a load case can be selected by clicking the load number with the left
mouse button. Groups of loads can be selected by click and dragging the mouse. Extra loads can be added to the
selected group using Ctrl + Left Mouse key. Changes to the load arrangement after the selection is made, by adding or
removing loads or modifying concrete shapes, will void any selection.

Paste:- Paste the selected loads. The Paste Option will only be available after a legal copy has been performed
and the data grid into which the data is to be pasted is selected as follows; If a data row is selected by selecting the
load number cell, the copied loads will be inserted at the row selected and all other data rows will be moved down to
accommodate the pasted loads. If no data row is selected the copied loads will be added to the end of the existing
loads. Multiple data rows cannot be selected for the paste operation. The paste can be into any load of the same type
in any load case, e.g. moving line loads can only be copied to moving line loads. RAPT automatically creates the space
in the data grid into which the loads are to be copied, so it is not necessary to create the rows for the data to be
inserted into.

Data Definition

Left End of Load from End of Previous Load

The distance from the end of the moving line load to the left of this load to the left end of the load.

Load at Left End

Value of the load at the left end of the load in force/length.

Length of This Load

The length of this load.

Load at right end

Value of the load at the right end of the load in force/length.

Impact Factor
The Impact factor associated with this load as defined in the relevant loading code. RAPT will multiple the load by this
factor when including it in any load combination.

Description
Designer's description of the load. This is not a compulsory data field.

7.2.4.1.4.2 Moving Area Loads

A load defined as load/length2. The load value is constant over the length of the load. The load is applied over a user
defined width which can vary over the length of the load thus requiring the input of a width at the left end and a width
at the right end of the load (as shown below). Positive loads are downwards. In two-way slab analysis, line loads are
divided between column and middle strips using the factors in 7.2.4.3 frame_input_lateral_factors.htm.

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Area Loads Toolbar

The default button in the loads dialogs is always OK (shows 3D or expressed). If the focus is in an edit cell, the OK
button will always accept an Enter key press without having to move the focus to it. Pressing enter while in the edit
cells will accept the data and insert the load as defined. Adding the load can be cancelled by clicking on or moving to
and pressing enter on the Cancel Button.

If using the keyboard to navigate around the dialog, use the Tab key (forwards or Shift + Tab key (backwards) to
move the focus. Using the Tab key at the end of a row will move focus to the start of the next row.

A blank cell is regarded as having a value of zero.

Add general moving trapezoidal load:- Will add a constant load defined as load/length2 with a linearly varying
width over the length nominated. The dialog below will be presented for input of the load start and end locations, load
width values and the load. Data focus is initially in the Distance From Last Load cell. When the start load width value is
initially entered, the end load width value will default to the same value creating a uniformly distributed load. The
designer can over-ride this default end value to create a linearly varying width of load. RAPT will refuse to add the load
if the load length is negative or if one of the ends is outside the frame or if the two load width values are zero or if the
load is zero.

Add multiple moving trapezoidal loads:- Will add multiple linearly varying load width over the lengths
nominated. The dialog below will be presented for input of the load start, load lengths, load width and load values.
Data focus is initially in Distance From Last Load cell. When the start load width value is initially entered, the end load
width value will default to the same value creating a uniformly distributed load. The designer can over-ride this default
end value to create a linearly varying load width. RAPT will refuse to add the load if the load length is negative or if
one of the ends is outside the frame. A load segment can have zero load widths at both ends. RAPT will insert this as a

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gap in the load pattern of the length defined.

Add Concentrated moving load:- Most point loads actually apply load over at least the length of the item
applying the load e.g. a transverse wall has a thickness. Many design codes also allow these loads to be distributed
over an even wider area. Even though a point load is being defined, RAPT will apply it as a distributed load over the
load length.

RAPT allows the designer to define a point load as a load/width with a width of load a length over which the load is
applied. The load will be applied centred at the defined load location. The designer should ensure that the full extent of
the load will be within the frame length.
As well as defining a load location and a load value and load width, the designer is asked for a Load Length. The width
and length cannot be zero. If a knife-edge load is required (zero load length), input it under the 7.2.4.1.1.4 Point Load
input.

Add Number of moving Loads:- RAPT will allow the user to define a number of loads and create the space for
these loads in the data grid. No load values will be input by RAPT. The designer must add all load data for these loads.
This has been done to allow designers to copy loads from another data source (either another loads grid in RAPT or
from an external spreadsheet) into the RAPT data fields.

Delete load:- Deletes the selected loads. The loads must be selected by clicking on the load number cell. Multiple
loads and non-continuous groups of loads can be selected using the 4.4.3 Cell Selection rules.

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Copy:- Copy a selected group of loads for to memory for later Paste operation. The Copy option will only be
available after a legal selection is made. Any loads in a load case can be selected by clicking the load number with the
left mouse button. Groups of loads can be selected by click and dragging the mouse. Extra loads can be added to the
selected group using Ctrl + Left Mouse key. Changes to the load arrangement after the selection is made, by adding or
removing loads or modifying concrete shapes, will void any selection.

Paste:- Paste the selected loads. The Paste Option will only be available after a legal copy has been performed
and the data grid into which the data is to be pasted is selected as follows; If a data row is selected by selecting the
load number cell, the copied loads will be inserted at the row selected and all other data rows will be moved down to
accommodate the pasted loads. If no data row is selected the copied loads will be added to the end of the existing
loads. Multiple data rows cannot be selected for the paste operation. The paste can be into any load of the same type
in any load case, e.g. moving area loads can only be copied to moving area loads. RAPT automatically creates the
space in the data grid into which the loads are to be copied, so it is not necessary to create the rows for the data to be
inserted into.

Data Definition

Left End of Load from End of Previous Load

The distance from the end of the moving area load to the left of this load to the left end of the load.

Width at Left End of Load

Width of the loaded area at the left end of the load. RAPT does not attempt to relate this width to any dimension of the
structure.

Length of This Load

The length of this load.

Width at Right end of load

Width of the loaded area at the right end of the load. RAPT does not attempt to relate this width to any dimension of
the structure.

Load
The load in load/length 2 which is applied on the loaded area defined above.

Impact Factor
The Impact factor associated with this load as defined in the relevant loading code. RAPT will multiple the load by this
factor when including it in any load combination.

Description
Designer's description of the load. This is not a compulsory data field.

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7.2.4.1.4.3 Moving Point Loads
A load defined as concentrated point load. RAPT allows a concentrated load to be defined with a length over which the
load can be spread. If the Load Length is defined as zero, the load is treated as a knife-edge load so it's effect will be
concentrated at the point of application. In design, RAPT will place design points immediately to each side of the load
to trap the critical shear values. This type of load is very severe and rarely occurs like this in practice. Normally a
concentrated load will have a length of application which will tend to smooth the effect of the load and reduce the
design moments and shears caused by it. To achieve this, the user can define the load length in the Point Load screen,
or use the various versions of 7.2.4.1.1.1 Concentrated Linear Loads for Line, Area and Panel loads.
Positive loads are downwards. In two-way slab analysis, point loads are divided between column and middle strips
using the factors in 7.2.4.3 frame_input_lateral_factors.htm.

Point Loads Toolbar

The default button in the loads dialogs is always OK (shows 3D or expressed). If the focus is in an edit cell, the OK
button will always accept an Enter key press without having to move the focus to it. Pressing enter while in the edit
cells will accept the data and insert the load as defined. Adding the load can be cancelled by clicking on or moving to
and pressing enter on the Cancel Button.

If using the keyboard to navigate around the dialog, use the Tab key (forwards or Shift + Tab key (backwards) to
move the focus. Using the Tab key at the end of a row will move focus to the start of the next row.

A blank cell is regarded as having a value of zero.

Add single point load:- Will add a single point load at the location nominated. The dialog below will be
presented for input of the load location, load value and load length. Data focus is initially in the Distance from Last
Load cell. RAPT will refuse to add the load if the load or any part of the load length is outside the frame or if the load
value is zero.

Add multiple point loads:- Will add a group of point loads at the locations nominated. The dialog below will be
presented for input of the reference column number, the distance from the last load for each load (for the first load it
is the distance from the reference column) and each load value and load length. Data focus is initially in the reference
column number cell. RAPT will refuse to add a load if the load or load length is outside the frame or if the load value is

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zero.

Add Number of Loads:- RAPT will allow the user to define a number of loads and create the space for these
loads in the data grid. No load values will be input by RAPT. The designer must add all load data for these loads. This
has been done to allow designers to copy loads from another data source (either another loads grid in RAPT or from an
external spreadsheet) into the RAPT data fields. This is needed for the Windows Copy/Paste functions but is not
needed for the RAPT Copy/Paste functions described below which will automatically create the data rows as required.

Delete load:- Deletes the selected loads. The loads must be selected by clicking on the load number cell. Multiple
loads and non-continuous groups of loads can be selected using the 4.4.3 Cell Selection rules.

Copy:- Copy a selected group of loads for to memory for later Paste operation. The Copy option will only be
available after a legal selection is made. Any loads in a load case can be selected by clicking the load number with the
left mouse button. Groups of loads can be selected by click and dragging the mouse. Extra loads can be added to the
selected group using Ctrl + Left Mouse key. Changes to the load arrangement after the selection is made, by adding or
removing loads or modifying concrete shapes, will void any selection.

Paste:- Paste the selected loads. The Paste Option will only be available after a legal copy has been performed
and the data grid into which the data is to be pasted is selected as follows; If a data row is selected by selecting the
load number cell, the copied loads will be inserted at the row selected and all other data rows will be moved down to
accommodate the pasted loads. If no data row is selected the copied loads will be added to the end of the existing
loads. Multiple data rows cannot be selected for the paste operation. The paste can be into any load of the same type
in any load case, e.g. point loads can only be copied to point loads. RAPT automatically creates the space in the data
grid into which the loads are to be pasted, so it is not necessary to create the rows for the data to be inserted into
before the paste operation is performed.

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Data Definition

Distance to Load from previous load of this type

The distance from the centre of the last point load to the centre of this point load.

Load
Value of the load.

Load Length
Length the point load will be spread over, centred on the load location. If set to 0, the load will be treated as a knife-
edge point load. If a length is defined, the load will be spread as a distributed load over the length defined. This length
must be fully within the frame.

Impact Factor
The Impact factor associated with this load as defined in the relevant loading code. RAPT will multiple the load by this
factor when including it in any load combination.

Description
Designer's description of the load. This is not a compulsory data field.

7.2.4.1.4.4 Moving Loads Details

This screen allows the designer to define the way in which the moving load pattern is to move along the frame.
RAPT determines the locations to position the moving load pattern in the following manner:

1. The start end of the loading pattern in the direction of movement is placed at one full increment from the
start of the frame in that direction of movement. The load pattern is then moved in the direction of
movement in increments until the entire moving load pattern clears the far end of the frame. If the designer
places limits on the extent over which the load is to be able to travel, the loading pattern will only be placed
on the frame once the complete pattern can fit in between the limits defined.
2. Special locations at each support as defined below.

The centre of the moving load pattern is determined as the mid-length between the start of the first load and the end
of the last load in the pattern.
Special Locations:
RAPT determines the load locations required for Special Positions to achieve the following

1. All point loads are placed at the special location.

2. The 1/3rd points and locations of all distributed loads are placed at the special location.
3. The mid point between the end of one load (or a point load location) and the start of the next load is placed
at the special location

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Data Definition

Number of equally Spaced Points in each Span to Locate Moving Load Pattern
In each span, RAPT will initially determine the increment of movement of the moving load pattern by dividing the span
length by the number of equally spaced points in each span.

Maximum Increment for Each Move

The Maximum Increment of Movement will be used to limit the increment of movement of the moving load pattern
determined based on the number of points above.
Direction in which Load is to Move
RAPT offers 3 direction of movement options listed below.

1. Left to Right:- The defined moving load pattern will be placed at the locations defined above.
2. Right to left:- The moving load pattern will be turned around and placed at the locations defined above to
simulate the same pattern travelling from right to left.
3. Return:- Both options 1 and 2 will be used.

Limit Left Extent of Moving Load

Allows the designer to define an area at the left end if the frame on which the moving load does not travel. The
moving load pattern will not be placed on the frame until the complete length of the load pattern is clear of this length
of the frame.
Left Extent Reference Column
Distance from Left Reference Column To Left Load Extent Limit
The location of the left end extent limit of the load pattern.

Limit Right Extent of Moving Load

Allows the designer to define an area at the left end if the frame on which the moving load does not travel. The
moving load pattern will not be placed on the frame until the complete length of the load pattern is clear of this length
of the frame.

Right Extent Reference Column

Distance from Left Reference Column To Right Load Extent Limit
The location of the right end extent limit of the load pattern.

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7.2.4.2 Load Combinations

The 7.2.4.1 load cases defined by the designer must be combined in various ways to be used in the design process.
RAPT divides these combinations cases into 5 groups for design purposes.

1. 7.2.4.2.1 Ultimate:- Used for ultimate strength design for both flexure and shear. Multiple combination cases
can be defined. RAPT will use the combination cases defined here to create two ultimate design envelopes.
These are
1. Moment controlled envelope in which the extreme moments at each design location are determined
with their co-existing shears. This case is used for ultimate flexure design and ultimate shear design.
2. Shear controlled envelope in which the extreme shears at each design location are determined with
their co-existing moments. This case is used for ultimate shear design.
2. 7.2.4.2.2 Short term Service:- Used for serviceability design for flexure. Multiple combination cases can be
defined. RAPT will use the combination cases defined here to create a short term load service design
envelope.
3. 7.2.4.2.3 Permanent Service:- Used for serviceability design for flexure for some design codes. Multiple
combination cases can be defined. RAPT will use the combination cases defined here to create a permanent
load service design envelope.
4. 7.2.4.2.4 Deflection:- Used for three of the deflection cases. Individual combination cases each produce one
bending moment/shear diagram. These combination cases are not enveloped.
5. 7.2.4.2.5 Transfer Prestress:- Used for prestress transfer calculations and Transfer deflection calculation for
all members.
6. 7.2.4.2.6 Pre-Existing:- Used to define the load combination that determines the stress condition in the
concrete when strengthening works are being carried out and reinforcement of some type is being attached to
the concrete.

All of the available load cases are defined across the top of the data window. Factors can be applied to each load case
for each combination case for each design option.
For all design cases, RAPT creates a set of default combination cases based on the requirements of the relevant design
standard and the factors defined in 5.7 Design Standard->Load Combinations. These are created for the default
building type (Office) or 7.2.1 requested building type in the input dialog. The designer is free to modify these
combination factors as appropriate for the design situation. A different building type can be selected from the toolbar.
If an Alternate load case is defined in 7.2.4.1 Load Cases, it is shown in the data window with the combination values
assigned to the basic load case it is associated with in each combination case. These values are not able to be edited.
The same factor must apply to all loads of that type as an envelope of the load type is created. To change the factor
do so in the data column for the basic load case for that type (e.g. Live Load and Alternate Live Load cases).
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Load Combinations Toolbar

Add Load Combination:- Add combination case to the current design option. If a data row is selected by
clicking on the left end cell in the row, the new combination case will be added at this location and the rows at and
below this position will be shifted down. The combination case is added with all factors set to zero. The designer can
then apply factors to any of the load cases available for this design option. This option is not available for deflection
and transfer combinations.

Delete Load Combination:- Deletes the selected combination case/s from the current design option. Multiple
combination cases can be deleted at once using the selection logic in 4.4.3 Cell Selection. Program calculated cases
can be deleted. This option is not available for deflection and transfer combinations.

Change Building Type:- Resets the program defined load combinations to the defaults for the selected
building type. Any user defined combination cases will be retained. This will reset the combinations for all five design
cases, not only the one in which the toolbar button was selected. Selecting this toolbar button will indicate which
Building Type was used as the basis for the current combination case settings. The default values for each building
type are defined in 5.7 Design Standard->Load Combinations. For all except the User Defined Building Type, the
factors are shown for information purposes only. They cannot be edited in this dialog. Once the building type has been
accepted and the combination cases created with the new factors, the designer can then modify factors and add and
remove combination cases for all building types.

The building types available are:-

1. Domestic
2. Parking
3. Office
4. Retail
5. Storage
6. Roof
7. Other
8. User-Defined - Allows the designer to edit the values for each factor and create their own building type.

The load factors that can be defined are

Ultimate Load Factors

Some load types require two factors. These factors are

1. Adverse:- The load effect in question is of the same sign as the sum of remainder of the load effects at this
point and will lead to an increase in the overall effect.
2. Beneficial:- The load effect in question is of the opposite sign to the sum of remainder of the load effects at
this point and will lead to an reduction in the overall effect.

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The load types defined are

1. Prestress:- Two factors are required, one for Adverse effects and one for Beneficial. Some design codes do
not differentiate for this and a value of 1.0 is used for both factors.
2. Dead Load:- Two factors are required, one for Adverse effects and one for Beneficial. Instead of applying the
two factors for Dead Load as adverse/beneficial effects in a single calculation, RAPT will create separate
combination cases for the two factors and will create an envelope of the effects. Dead load factors apply to all
self weight and superimposed dead load cases.
3. Live Load:- Factor applied to live load cases in the Live Load Combination Cases.
4. Wind Load:- Factor applied to applied wind load to determine the ultimate wind loading. Some design
standards actually specify separate loadings for service design and ultimate design. RAPT assumes a service
wind loading is being applied and that the ultimate wind loading is determined as a factor times this.
Sometimes the factor may vary depending on the building and the wind design parameters. It is up to the
designer to make these changes for each particular design.
5. Earthquake Load:- The factor applied to the earthquake loading for ultimate strength. Some design
standards define a service loading with a multiplying factor while others define an ultimate earthquake
loading. The designer should ensure that the appropriate factor has been set for the loading type defined.

Partial Load factors

These factors are used on the live load for various conditions explained below.

1. Tc:- Combination factor. Used for live load when it is combined with other variable actions such as wind load
for ultimate strength combinations.
2. Tm:- Combined Load Multiplying factor used in some codes.
3. Ts:- Short Term Service Load factor.
4. Tl:- Long Term (Permanent) Service Load factor.

The following shows how these factors are used in relation to the various codes.

1. AS3600
Tc - Combination live load factor used in assessing the design load for strength
Tm - Multiplying factor = 1.
Ts - Short term live load factor used in assessing the design load for serviceability
Tl - Long term live load factor used in assessing the design load for serviceability
2. Eurocode2
Tc - (To in Eurocode2) Combination coefficient for representative value of a variable action. [See Eurocode1
8.4 & Table 3, Notation)
Tm - Multiplying factor = 1.
Ts - (T1 in Eurocode2) Combination coefficient for frequent value of a variable action.
Tl - (T2 in Eurocode2) Combination coefficient for quasi-permanent value of a variable action.
3. ACI318
Tc - Combination factor = 1.
Tm - Multiplying factor used in assessing the design load for strength. [See ACI318 Clause 9.2.2 & 9.2.3 - Tm
= 0.75].
Ts - Short term live load factor used in assessing the design load for serviceability.
Tl - Long term live load factor used in assessing the design load for serviceability.
4. BS8110, CP65, CP2004, IS456/IS1343 & SABS0100
Tc - Combination factor = 1.
Tm - Multiplying factor used in assessing the design load for strength. [See BS8110 Table 2.1 Case 3 - *m =
1.2].
Ts - Short term live load factor used in assessing the design load for serviceability.
Tl - Long term live load factor used in assessing the design load for serviceability.

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7.2.4.2.1 Load Combinations - Ultimate

7.2.4.2 TOOLBAR

Data Definition
Down the left side the combination cases are listed with a number and a description. Across the top of the data view,
the available load cases are listed. A column of data will be made available for each load case defined in the 7.2.4.1
Load Cases data screens. If the member is prestressed, extra columns will be available for factors for prestressing
effects.

As load cases are added in the 7.2.4.1 Load Cases window, they will be added to new columns in this window. If the
load case is of a known type it will be given default values for the current building type from the Building Type Data. If
the load case is not of a known type, it will be assigned a column of data but all factors will be zero. Factors must be
added by the designer to the combination cases as required for this load case.

Each combination case can have a different multiplying factor applied to each load case. The exception to this is
Alternate Cases The values for Alternate Cases are read only and are not able to be edited. The same factor must
apply to all loads of that type as an envelope of the load type is created. To change the factor, do so in the data
column for the basic load case for that type (e.g. for Live Load and Alternate Live Load cases use the Live Load factor
in each combination case). This will change the load factor for all related load cases.

Description
A text field allowing the designer to name each combination case. Program defined combination cases are named
automatically and the name cannot be modified. The names used for the default combination cases are

1. Live Load:- Cases from the relevant design standard which combine dead loads and live loads.
2. Dead Load:- Cases from the relevant design standard which combine dead loads only. For design standards
that do not define such a combination, RAPT uses the average of the DL and LL factors and applies this factor
to the dead loads only.
3. Wind Load:- Cases from the relevant design standard which combine dead loads, live loads and wind loads.
4. Earthquake:- Cases from the relevant design standard which combine dead loads, live loads and
earthquake loads.

Prestress Secondary Adverse

Prestress Secondary Beneficial
For ultimate strength, only the long term Secondary Prestress load case can be selected. Some Design Standards
place different factors on this depending on whether or not the secondary prestress effect at a point increases the
applied moment (Adverse) or reduces the applied moment (Beneficial). RAPT will apply whichever of these factors is
appropriate at each design location.
The other load cases are self-explanatory.

In design, two envelopes of the effects of all of the combination cases will be calculated, one based on an envelope of
moments and the second based on an envelope of shears. These will be available for viewing in the output.

7.2.4.2 Frame Definition and Design: Load Combinations 4