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Chapter VIII Hangers

EDC - ITBTraining on Caesar II

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B A B VIII

HANGERS

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8.1 General Information

Input Piping Model Hanger Design Control Data

Zero load constant effortsuppor

Stiff (Default) : 1.0E12

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8.2 Simple Hanger Design

No additional input

Globally (in hanger

control)locally (on eachhanger auxiliary dataarea)

Note that a number of the parametersfrom the hanger control sheet also showup on the individual hanger auxiliarydata fields.

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8.3 Single Can Design

distance betweenthe pipe support and theconcrete foundation, or

baseplate.

Indicate that the pipe is supported from below by entering a negative number in theHanger/Can Available Space field on the

hanger spreadsheet.

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8.4 Constant Effort Support Design

Constant effort support

Very small allowable travel

0.01 in

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8.5 Inputting Constant Effort Supports (No Design)

1. Enter the constant effortsupport load (per hanger)in the Predefined HangerData field.

2. Enter the number ofconstant support hangers atthe location.

Step :

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8.6 Entering Existing Springs (No Design)

1. Enter the Spring Rate andthe Theoretical Cold Load(installation load, on a perhanger basis) in thePredefined Hanger Datafields.

2. Enter the number of

Variable Support Hangersat the location.

Step :

Theoretical Cold Load = Hot Load +Travel * Spring Rate

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8.7 Multiple Can Design

Positive number

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8.8 Old Spring Redesign

the hanger table the number of springs

at the location

the old spring rate

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8.9 Pipe and Hanger Supported From Vessel

Connecting nodesassociated with hangersand cans function justlike connecting nodeswith restraints.

Connecting nodedisplacements are

incorporated in thehanger design algorithm.

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8.10 Hanger Design with Support Thermal Movement

The hanger at node 9 issupported from astructural steel extensionoff of a large verticalvessel. The vessel at the

point where the hanger isattached grows thermallyin the plus Y

direction approximately3.5 in.

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8.11 Hanger Between Two Pipes

The directive Connect Geometry through CNodes must be turned offin the

Configuration Setup to avoid plot and geometry errors.

Node on the pipe passing overhead

Rigid element

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8.12 Hanger Design with Anchors in the Vicinity

the anchor at 5 is freed in the Y-direction,the anchor at 105 is freed in all directions.

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8.13 Hanger Design with User-Specified Operating Load

In this configuration, freeing the anchors at 5 and 60 didnt help the thermal case nozzle loads.It was postulated that, due to the stiffness of the overhead branches, the hanger calculated hotload was not sufficient. The calculated hot load was 2376 lb. A new hot load of 4500 lb. is triedhere.

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8.14 Spring Can Models with Bottom -Out and Lift -Off

CapabilityGrinnell, fig.B268, size 10 : theoretical cold load: 1023 lb. spring rate : 260 lb./in. smallest load : 910 lb. largest load : 1690 lb.

Bottom out :

in4346.0260

1091023rateSpring

LoadMin.TableLoadInstalled

Lift-off :

in565.2

260

10231690

rateSpring

LoadInstalledLoadTable.Max

Value for the gaps g1 = 0.4346 g2 = 0.4346 + 9.1E-6 g3 = 2.5650

Min. Table Load : 910 = 9.1E-6 in

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Example: Input for Lift-off and Bottom-out Spring Can Model (continued)

The gap field in the restraints auxiliary data area rounds off values to 3 decimal places for display only. Internally, CAESAR II stores values to 7 digits forcalculations. Therefore the gap corresponding to the -Y restraint in this examplewas input as 0.4346 + 9.1e-06 and this value will be retained in memory for

calculations.

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8.15 Spring Hanger Model With Rods, Bottom -Out, and Lift -Off

Grinnell, fig.B268, size 10 : theoretical cold load: 101 lb. spring rate : 200 lb./in. smallest load : 600 lb. largest load : 1300 lb.

Bottom out :

in055.2260

0601011rateSpring

LoadMin.TableLoadInstalledLift-off :

in445.1200

10111300rateSpring

LoadInstalledLoadTable.Max

Value for the gaps

g1 = 0.4346 g2 = 0.4346 + 9.1E-6 g3 = 2.5650

Min. Table Load : 600 = 6.0E-6 in

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Dummy rigid modeled between nodes 10 and15. Pipe connected to the rod through a +Yrestraint.

Example: B ottom-out and L if t-off Spri ngH anger M odel with Rods

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8.16 Simple "Bottomed-Out" Spring

Gap : x (permitted travel)

Mu : F (initial load)

Note that no hanger should be entered at the same position as a bottomed-out spring.

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8.17 Modeling Spring Cans with Friction

A rigid element from the pipe center to the top of the can. Lengthequals pipe radius + insulation thickness + shoe height + anytrunnion height.

A Cnode to connect to the spring. Except for the vertical spring

stiffness, all other DOFs are rigidly connected. A rigid element representing the spring can height.

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