PCF Restraint Mapping - CAESAR II - Help

The PCF_RES_MAP.TXT file defines the CAESAR II restraint types corresponding to PCF support/restraint names.

CAESAR II uses the SUPPORT mapping component to apply supports at the specified coordinates. If the software is unable to match a SUPPORT with a <SUPPORT_NAME> keyword in the PCF_RES_MAP.TXT file, only the SUPPORT-DIRECTION attribute is interpreted by the software. The SUPPORT-DIRECTION attribute must have a value of UP, DOWN, EAST, WEST, NORTH, or SOUTH.

Support configurations can vary from project-to-project. In order to fine-tune the configuration CAESAR II uses with an imported model for a given SUPPORT component, you need to map an attribute to the <SUPPORT_NAME> keyword in the PCF_RES_MAP.TXT file.

The following example displays a typical SUPPORT component. The attribute definition (VG100) for the NAME attribute is highlighted and should be used to define CAESAR II support mapping.

Remember that, as your support configuration changes, you can customize this mapping file to ensure proper import into the software.

To Modify the PCF_RES_MAP.TXT File

Locate the PCF_RES_MAP.TXT file in the CAESAR II system folder.

This file defines the CAESAR II function corresponding to PCF support/restraint names.

This is an optional task. You can review the default file and determine if you need to make changes to fit your model.

1. Open the PCF_RES_MAP.TXT file in any text editor, such as Notepad.

2. Modify any of the attribute customization options or restraint definitions.

3. Save, and close the file.

Defining PCF Keywords

In the Keyword Mapping Section, define an attribute from your PCF file to associate with the following CAESAR II keywords:

• <SUPPORT_NAME>

• <SUPPORT_TAG>

• <SUPPORT_GUID>

The CAESAR II keywords located within "<>" are used in the PCF import process. The <SUPPORT_NAME> keyword is used by CAESAR II to map the supports. The <SUPPORT_TAG> and <SUPPORT_GUID> keywords are support properties that are imported into CAESAR II.

Defining Support Mapping

In the Support Mapping Section, define the support mapping.

In the following example file, VG100 corresponds functionally to two CAESAR II supports:

• +Vertical support (weight support)

• Guide, each with friction coefficients equal to 0.3

This file supports a wide range of support functions, plus the key words MU= (for friction) and GAP= (to define gaps in the restraint).

The syntax for each support type is:

<Support Name> <N>

<Restraint Function> <MU=> <GAP=>

When creating the blank space use the Space Bar. Do not use the Tab key.

<Support Name>

CAESAR II attempts to match the <Support Name> with the attribute definition from your PCF mapping file. Any attribute definition in the PCF file that contains the <Support Name> is considered a match (it does not have to be an exact match). For example, if the <Support Name> is VG1, an attribute definition such as VG100 would be considered a match.

For optimal results, list the <Support Names> in the order from longest name to shortest name. Otherwise, if you have both VG1 and VG100 as <Support Names>, the software reads VG1 as a match before VG100 is processed.

<N>

Specifies the number of CAESAR II restraints to be placed in the corresponding Restraint auxiliary panel in the Piping Input. CAESAR II allows up to six restraints on any element.

<Restraint Function>

Specifies the purpose/type of restraint (GUI, LIM, VHGR, and so forth.), Global Axes (VERT, NS, EW, and so forth), or Local Axes (a, b, c, and so forth):

• ANC, GUI, LIM, VHGR, CHGR

Creates a CAESAR II Anchor, Guide, Axial Restraint, Variable Hanger, or Constant Hanger, respectively. The variable and constant attributes create to-be-designed hangers, which may end up as either variable or constant hangers.

• VERT, EW, NS

Indicates a translational restraint that corresponds to the compass points of the global axes (Y, X, Z respectively for the Y-up setting, and Z, X, Y respectively for the Z-up setting). See the figure below. Create one-way restraints by prefixing the attribute with "+" or "-".

• A, B, C

Indicates a translational restraint that corresponds to the local axes of the support/pipe installation. The A corresponds to the centerline of the pipe, B corresponds to the "direction" attributed to the support, and C corresponds to the cross-product of the A and B axes. As with the global restraints, one-way restraints may be created by prefixing with + or -. See the figure below.

<MU=>

Optional keyword followed by a value for adding a friction coefficient to the restraint. (This keyword is not valid with ANC, VHGR, CHGR.)

<GAP=>

Optional keyword followed by a value and set of units for adding a gap to the restraint (This keyword is not valid with ANC, VHGR, CHGR.)

The software also processes equipment nozzles designated by the END-CONNECTION-EQUIPMENT keyword as imposed thermal displacements in all degrees of freedom, all with values of 0.0. This creates an initial behavior of an anchor but allows you to easily impose actual thermal displacements when known.

Examples

The examples below illustrate typical restraint configurations, along with suggested mapping entries.

Variable Spring Hanger

These represent variable spring hangers and are mapped onto a single CAESAR II support (= VHGR). This is interpreted as a program-designed spring hanger in CAESAR II.

Constant Effort Spring Hanger

This represents a constant effort spring hanger, and thus is mapped onto a single CAESAR II support (= CHGR). This is treated as a program-designed spring hanger in CAESAR II. Note that it is identical to the VHGR shown in the figure above.

These hanger rod assemblies only resist downward (weight) loads and allow upward movement. In CAESAR II, they are typically modeled as +Y (or +Z, depending on how the vertical axis is set).

These sliding supports only resist downward (weight) loads and allow upward movement. They are represented as a single +VERT support. However, because they slide against a base, most stress analysts prefer to add a friction coefficient (MU=x.xx).

These restraints resist load/movement in both directions (so the "+" of the previous two supports is eliminated). If the restraint is always installed vertically, then use the first definition (VERT). If the restraint is installed in any direction (for example, vertically or horizontally), use the second definition B, indicating that it acts along the installed support direction. This assumes that the installed direction of the restraint is always defined as the direction from the main steel towards the pipe. Because sliding is involved, a friction coefficient is included as well.

YRIGID 1

VERT MU=0.3

or

YRIGID 1

B MU=0.3

If this restraint is always installed vertically on horizontal lines (as shown in the figure above), then the support function can always be modeled as a Guide (with sliding friction). If the restraint may be installed in any direction at all (with restraint direction corresponding to the direction of the attachment point toward the pipe), then use the second definition (C) as it represents the direction lateral to the pipe and the restraint.

UGUIDE 1

GUI MU=0.3

or

UGUIDE 1

C MU=0.3

This restraint maps to two functions:

• +VERTical

• GUIde

TEESUPPORT 2

+VERT MU=0.3

GUI MU=0.3

Because sliding is involved in both functions, friction coefficients are provided for both.

VERTLATERAL 2

VERT MU=0.3

GUI MU=0.3

or

VERTLATERAL 2

B MU=0.3

C MU=0.3

This restraint maps to two functions:

• up/down restraint

• side-to-side restraint

If it is always installed vertically, then it is defined as a VERTical and a GUIde. If it is possible that the restraint may be rotated about the pipe to be installed in any direction, then use the second definition, which represents restraint along the direction of the support as well as lateral to the support and pipe.

VERTAXIAL 2

+VERT MU=0.3

LIM MU=0.3

or

VERTAXIAL 2

+VERT MU=0.3

A MU=0.3

This restraint maps to two functions:

• +VERT support

• An axial restraint. The axial restraint can be defined equally as LIM or A (as A corresponds to restraint along the direction of the pipe centerline).

SWAYSTRUT 1

B

These represent sway struts, which may be installed in any direction, and provide restraint along the line of action of the sway strut. Assuming that the restraint direction corresponds to the direction of the sway strut, then the best way to define these restraints is B (restraint along the support direction).

ANCHOR 1

ANC

These restraints all restrict movement of the pipe in all six degrees-of-freedom, so they can be defined as Anchors ("ANC").

PENETRATION 4

+C GAP=aMM

-C GAP=bMM

-VERT GAP=cMM

+VERT GAP=dMM

In the example above, the pipe (and the local A-axis) is running into the page. With B up, +C is to the right.

Some of these can get quite complex, especially if restraints have different gaps in different directions. It may require trial and error to determine exactly how the +/- restraint directions correspond to the support direction passed in the PCF. In some cases, you may want to model the restraint behavior in CAESAR II rather than in the mapping file.