Dynamic Analysis of Independent Support Earthquake Excitation (CRYNOS) - CAESAR II - Reference Data

CAESAR II Applications Guide (2019 Service Pack 1)

PPMProduct
CAESAR II
PPMCategory_custom
Reference Data
Version_CAESAR
11.0 (2019)

This example explains how to model a cryogenic piping system in accordance with B31.3 using specific ground, building, and envelope spectra. The two analyses that are run in this example assume the pipe (structural steel) supports are rigid and include the flexibility of the structural steel supports by including the steel frames in the analysis. Finally, compare the results from the two analyses. The design parameters are:

  • Ambient temperature: 100°F

  • Operating temperature: -59°F

  • Pipe: 8-inches Sch 10S

  • Insulation: 4-inches 22.3 lb/cu feet

  • Insulation: 0.232 SG

  • Columns: W14x82

  • Beams: W10x12

The isometric of the complete model is shown in the following figure. This drawing shows the piping, pipe supports, and the structural steel frames

.

The following table lists the excitation spectra to be applied to this model:

Ground Response Spectra Ground Response

Building Response Spectra Building Response

Envelope Response Spectra Envelope Response

T sec

V in/sec

T sec

V in/sec

T sec

V in/sec

0.05

0.787

0.05

0.787

0.05

0.787

0.2

7.874

0.2

1.3

0.2

7.874

0.5

21.653

0.5

3.4

0.5

21.653

1

39.37

1

27.3

1

39.37

2

18.89

2

30.4

2

30.4

3.5

43.7

3.5

21.12

3.5

43.7

5

11.8

5

21.3

5

21.3

10

5.9

10

5.359

10

5.9

The necessity for the various spectra can be best understood by investigating the difference between independent support excitation and uniform support excitation. These excitation methods are shown in the following figures.

For the analysis with steel supports, the structural steel must be included as part of the piping model. Click Environment > Include Structural Input Files. The structural data input is shown below:

SECID=1, W14 X 82; COLUMN CROSS SECTION

SECID=2, W10 X 12; BEAM CROSS SECTION

MATID=1, YM=29E6 POIS=0.3 G=11E6 DENS=0.283

DEFAULT SECID=1

ANGLE=90

EDIM 1038 1039 DY=15-0; DEFINE ALL COLUMNS

EDIM 1043 1044 DY=15-0

EDIM 1048 1049 DY=15-0

EDIM 1053 1054 DY=15-0

DEFAULT SECID=2

ANGLE=0

EDIM 1039 1040 DZ=-2-0;DEFINE ALL BEAMS

EDIM 1044 1045 DZ=-2-0

EDIM 1054 1055 DZ=-2-0

FIX 1038 ALL

FIX 1043 ALL

FIX 1048 ALL

FIX 1053 ALL_

The dynamics input for this example is summarized in the following figure:

Details of the dynamics input are shown in the next four figures.




Only the results for the uniform support excitation case are shown. Using this load case, the model with and without structural steel supports is compared. The results from these two models are shown in the following tables.


With Structure


Without Structure


With Structure


Without Structure


With Structure


Without Structure