Local Restraints Report - CAESAR II - Help

CAESAR II Users Guide

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CAESAR II
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CAESAR II Version
12

Generates a restraint report where the loads and moments are aligned with the local element coordinate system. This is particularly useful when addressing skewed nozzles, where the axial, longitudinal and circumferential results are needed. As an example, consider the small system shown below:

This system consists of two small horizontal lines anchored at both ends. The last element of each line is skewed 45 degrees in the X-Z plane. At the end of this skewed line is an axial restraint, as illustrated in the following figure:

The typical Global Restraint report for this system displays in the following table. At node 140, this report shows two equal loads in the (global) X and Z directions. These values (24,463) are the global component loads acting on the skewed restraint. The actual magnitude of the restraint load, acting in-line with the pipe can be found by performing the SRSS of these component loads, which yields 34595. This value is the load on the restraint acting axially with the pipe.

Operating Case Restraint Loads – Global Coordinate System

NODE

FX lb.

FY lb.

FZ lb.

MX ft.lb.

MY ft.lb.

MZ ft.lb.

100

-24463

-514

66

1340.5

-273.3

-6418.6

Rigid ANC

119

0

0

-24528

0.0

0.0

0.0

Rigid Z

140

24463

0

24463

0.0

0.0

0.0

Flex X

200

-24463

-514

66

1340.5

-273.3

-6418.6

Rigid ANC

219

0

0

-24528

0.0

0.0

0.0

Rigid Z

240

24463

0

24463

0.0

0.0

0.0

Flex X

The process of performing SRSS or sine/cosine operations to obtain restraint loads in the element coordinate system can be tedious. As an alternative, generate a restraint report where all loads are aligned with the associated element coordinate system. The report for the same small job displays in the table below.

Operating Case Restraint Loads – Local Element Coordinate System

NODE

fx lb.

fy lb.

fz lb.

mx ft.lb.

my ft.lb.

mz ft.lb.

100

-24463

66

514

1340.5

-6418.6

273.3

Rigid ANC

119

0

-24528

0

0.0

0.0

0.0

Rigid Z

140

34595

0

0

0.0

0.0

0.0

Flex X

200

-24463

66

514

1340.5

-6418.6

273.3

Rigid ANC

219

-17344

-17344

0

0.0

0.0

0.0

Rigid Z

240

34595

0

0

0.0

0.0

0.0

Flex X

In reviewing the relationship between the local versus global restraint loads note the following:

The global FY (vertical) load at node 100 of -514 translates to a local fz load. For details on the global to local coordinate system relations, see Technical Discussions. (These two values are shown in the tables in bold.)

At node 140, the skewed axial restraint, the first table showing the global coordinate system loads reports the two equal component loads. The second table showing the local loads, reports only the resultant axial load at the restraint. (These values are shown in the tables in bold.)