Autopipe Msrs Example1Xz

8/9/2019 Autopipe Msrs Example1Xz

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Description: AutoPIPE MSRS (ISM) Sample(Multiple Support Response Spectrum / Independent Support Motion)

Product: AutoPIPE

Version number: V8i (v9.2)

Submitted by: MURevison : 0.0

Table of Contents

Description: AutoPIPE MSRS (ISM) Sample ..............................................................Product: AutoPIPE ................................................................................................

Version number: V8i (v9.2) ...................................................................................

Submitted by: MU ................................................................................................

Revison : 0.0 .......................................................................................................

Table of Contents ..............................................................................................

FlowChart of a MSRS Model .................................................................................

Introduction to MSRS .........................................................................................

Sample Model : MSRS EXAMPLE.dat .....................................................................

Define Support Groups by SAM case ..................................................................

Define Modal Analysis Parameters .....................................................................

Assign Spectra to Support Groups .....................................................................

Run MSRS Analysis ...............................................................................................

Review Load Combinations ....................................................................................

Review On-Screen Results .....................................................................................

MSRS Result Reports ............................................................................................

MSRS Participation Factors for Each Support Group .............................................

MSRS Interpolated Spectral Results for Each Support Group .................................

Frequency Report ............................................................................................

Modal Result Reports ............................................................................................

Appendix A MSRS Parameters .............................................................................

MSRS Combination Sequence For Group And Modal Responses .............................

Groups before Modes = Checked.......................................................................


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Groups before Modes = Unchecked ...................................................................

Combining Rigid Or Missing Mass Responses ......................................................

Combining Responses within Support Groups .....................................................

CR6049-2 MSRS model Load Case and combination Defintitions ...........................

Calculating Interpolated Spectral Results ...........................................................

Appendix B References .......................................................................................


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FlowChart of a MSRS Model

Define Model

Add Support Groups by SAM case,and any imposed SAM

displacements

Assign Response Spectra & MSRS

analysis parameters

Review Load Combinations

Review MSRS Reports

Run MSRS Dynamic Analysis

Define Modal Analysis Parameters

Review On Screen Results


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Introduction to MSRS

49 | WWW.BENTLEY.COM

Multiple Support Response Spectrum Sept 2009

Spectrum 1

Spectrum 2

Spectrum 3

Independent Support Motion

In the upcoming V8i (V9.2) release is Multiple Support Response Spectrum Analysis, alscommonly known as independent support motion where groups of different supports arsupported on different structures which move independently in an earthquake or offshoplatforms subjected to wave motions. We can easily show the animated motion of thistype of dynamic loading and many different modal and spectral combination methods tosatisfy NRC benchmarks.

For piping systems subjected to multiple support response spectra (MSRS) orindependent support motions (ISM), such as the case for piping systems supported ondifferent buildings or at different floor levels, the motion of one set of supports could bequite different from the other. For such systems, the inertia or dynamic response can

analyzed using a uniform response spectrum analysis with a calculated single envelopespectrum for the different support groups. The pseudo static component of relativemotion between different support groups can be calculated using seismic anchormovement (SAM) analysis. The combined response can then be calculated by adding tdynamic (Uniform Response Spectrum) and SAManalysis results. This procedure, whicis relatively simple, can lead to overly conservative results.


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More realistic results can be obtained by using AutoPIPE Independent Support Motion(ISM) response spectrum analysis. This analysis is commonly used in the nuclearindustry (NUREG CR-1677, CR-6414 and CR-6049). The governing equations of motionfor this type of analysis may be expressed as follows (NUREG/CR-6049):

Although various methods and sequences for performing these combinations arepossible, the following specific and acceptable methodology can be used per NUREG/CR6049. The combination of group modal responses is first performed in accordance witheither the Grouping Method or the Double Sum Method as described in NRC RegulatoryGuide 1.92. The resulting group responses are next combined using the SRSS method(or ABS SUM for NUREG/CR-1677) to provide the combined modal response for all

flexible modes.

The missing mass or rigid response can be added to group modal responses using theSRSS method. At the end, the total responses from each spatial direction are combineusing the SRSS method.

Note: A group is a set of foundations which have the same motion. It is common forsupport groups at the same elevation in a tiered structure.


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Sample Model:MSRS EXAMPLE.dat

Define Support Groups by SAM case

1. Select the Supports for Group 1

First CTRL + Q to de-select all pointsEither

a) Hold CTRL key and click on the supportsb) Select a range of points, segments , window select or a good selection tools is

select by elevation range. The points or range selected will be colored RED

Hint: Change the Font to Arial Black and size = 12 under View > Settings so the poin

name can be clearly seen. Sometimes easier to see in Line instead of Solid RenderedMode.


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2. Select the Supports for Group 2

a) Select a range of points by clicking on point 6 and Hold Shift key and click on thepoint 16.Note: Only SAM/MSRS displacements for the supports and anchors in the rangeare added to the Imposed Displacement grid


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a) Insert > SAM / MSRS Support Group

b) Enter 2 in the Support Group No Field under SAM Case 1

c) View the Imposed Displacement Input Grid for the defined SAM Case andassigned support group and notice supports 7, 9, 11, 13, 15 are assigned to grou#2.


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3. Repeat to add support groups 3 & 4 for anchors 17 and 21 respectively

4. Enter following Non-zero SAM displacements into the Grid

NOTE: These displacements can be evaluated as typically done for seismic anchormovement (SAM) analysis. These non-zero SAM displacements are only needed if thpseudo static response needs to be evaluated. The pseudo static response determinthe effect of different support groups moving against each other statically. Refer toseismic anchor movement analysis in the online help for more information. Whenpseudo static displacements are added, the response spectrum case is typicallycombined with the corresponding SAM case using a user combination; In this case Rand S1 can be combined using SRSS or ABS SUM method.

Input GRID


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MSRS SpectrumSupport Groups


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Define Modal Analysis Parameters

Typically 33Hz for Seismic events, print frequency after cutoff to evaluate the nextclosest frequency.


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Assign Spectra to Support Groups

1. Load < Dynamic Analysis


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2. Select Response SpectrumTABUp to 50 Uniform or MSRS cases can be defined

a) Click the DefineButton to assign X, Y, Z spectra to each Support Group withingthe SAM case S1

Note: If the Spectra are not found in the same folder as the model then they are coloreRED as below. It is important to archive all Spectra (*.SPC) files with the AutoPIPE mod


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Note1 : Relative acceleration can only be calculated for MSRS casesFor other Uniform response cases, when this option is enabled (checked) the TotalAcceleration will be calculated for the corresponding load case. The Total Acceleration calculated by adding the ZPA acceleration, at the cut-off frequency, for each direction.When this option is disabled (unchecked) the Relative Acceleration will be calculatedinstead.Note2 : Group before modes is only enable for MSRS with SRSS as the modalcombination method.

Hint: A duplicate Response case R2 can be defined with Analyze Support Group = 1group only e.g. 2 and the response of this case compare with R1 or examine theseseparate group responses only.

Run MSRS Analysis


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Review Load Combinations

Response 1 load case


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SUS + R1 Default code combination e.g. for B31.1


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Review On-Screen Results

Result > Mode Shape to view Modal results

Mode 1 at 9.36 Hz


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Result > Displacement and select Response 1 to view MSRS displacements


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MSRS Result Reports

MSRS Participation Factors for Each Support Group

MSRS Interpolated Spectral Results for Each Support Group


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Frequency Report


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Modal Result Reports

File > Print Preview Modal Report to view detailed Modal Displacement, Local Force &Moments and Acceleration results in X, Y, Z and Resultant directions at each modalfrequency for each support group.


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Appendix A MSRS Parameters

MSRS Combination Sequence For Group And Modal Responses

If the user selects MSRS with SRSS as the modal combination method, then they canselect the option Groups before Modes,which is consistent with NUREG CR-1677.

Groups before Modes = Checked

WhenGroups before Modesis selected, the combination sequence is as follows:

First, group responses for each mode are combined using across groupcombination method (Abs sum orSRSS)

Spatial or X, Y, and Z components are combined next usingSRSS

Modal responses are combined next usingSRSS

Groups before Modes = Unchecked

Otherwise for MSRS the combination is done as follows: First, modal responses are combined using the selected modal combination meth

for each support group direction

The X direction responses for different support groups are combined using theacross group combination method.The Y and Z directional responses are combinesimilarly

Spatial or X, Y, and Z components are combined usingSRSS

The latter method has the advantage of combining signed modal responses like signed

CQC Methodand signedDoublesum Method. It is also consistent with NUREG methodslike CR-6049.

Combining Rigid Or Missing Mass Responses

In all cases, rigid or missing mass MSRS responses are combined as follows: Rigid group responses for each direction are combined using the across group

combination method

Spatial or X, Y, and Z components are combined usingSRSSto get total rigidresponse

Modal and rigid responses are combined using the missing mass combination

method

Combining Responses within Support Groups

The combination method within each support group is the algebraic sum method. Thismeans if a uniform spectrum case modeled as an MSRS, with a single support group foall the supports in the model, then the results for both analyses should be the same.
http://autopipe.chm/analyze/Group_before_Modes.htmhttp://autopipe.chm/analyze/Group_before_Modes.htmhttp://autopipe.chm/analyze/Group_before_Modes.htmhttp://autopipe.chm/analyze/Group_before_Modes.htm


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Note: For uniform response spectrum, modal combination is performed first, followed bspatialSRSScombination.

CR6049-2 MSRS Load Case and combination Defintitions

Common MSRS Flexible and Rigid mode combination methodology is found in CR6049-2below


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Modal Analysis : Hot modulus = T1

Pressure Stiffening = P1

18 modes

Loads Support Group Missing Mass Modal Comb

R1 1 None GroupingR2 2 None Grouping

R3 3 None Grouping

R4 All None Grouping

R5 All None Double Sum

R6 1 ABS SUM Grouping



R9 All SRSS Grouping

R10 All SRSS Double Sum

Load Combinations

GROUPING - GROUP 1 R1



TOTAL FLEX - GROUPING R4 Lower Frequency Amplified Response - Grouping Method

TOTAL FLEX - DOUBLESUM R5 Lower Frequency Amplified Response - DOUBLESUM Method

RIGID - GROUP 1 R6-R1



RIGID - TOTAL SRSS(RIGID - GROUP 1, RIGID - GROUP 2, RIGID - GROUP 3)

TOTAL - GROUPING R9 TOTAL Response - Grouping Method

TOTAL - DOUBLESUM R10 TOTAL Response - DOUBLESUM Method


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Calculating Interpolated Spectral Results


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Appendix B References

1. Bezler, P., M. Subudhi, M. Hartzman. Piping Benchmark Problems, Volume II,Dynamic Analysis Independent Support Motion Response Spectrum Method.NUREG/CR-1677 Vol II. Brookhaven National Laboratory, 1985.

2.

Piping Benchmark Problems for the General Electric Advanced Boiling Water ReactorNUREG/CR-6049 (BNL-NUREG-52377), Brookhaven National Laboratory, January1993, Prepared for the U.S. Nuclear Regulatory Commission, by P.Bezler, G. DeGrasJ. Braverman, Y.K Wang

3. Dynamics of Structures, Theory and Applications to earthquake Engineering by AniChopra

4. "Dynamics of Structures" by Clough & Penzien

Autopipe Msrs Example1Xz

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