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TR.5 Set Command Specification

This command allows you to set various general specifications for the analysis/design run.

General Format

SET { NL i1 | {DISPLACEMENT i2 | PDELTA TOLERANCE i9} | SDAMP i3 | WARP i4 | ITERLIM i5 | PRINT i7 | NOPRINT DIRECT | SHEAR | ECHO { ON | OFF } | GUI i6 | { Z | Y } UP | DEFLECTION CUTOFF  f1 | FLOOR LOAD TOLERANCE f2 | EIGEN METHOD { LANCZOS | RITZ} }

Where:

Description

The following SET commands contain values with associated units and should appear after a UNIT command and before the first JOINT command.

Table 1. Commonly used SET commands which take units
Command Parameter Description
SET NL i1 The SET NL command is used in a multiple analysis run if you want to add more primary load cases after one analysis has been performed. Specifically, for those examples which use the CHANGE command (see TR.38 Change Specification), if you want to add more primary load cases, the NL value should be set to the maximum number (or slightly more) with the SET NL command. The program will then be able to set aside additional memory space for information to be added later. This command should be provided before any joint, member or load specifications.

The value for i1 is the maximum number of primary load cases (NL). This value should not be much greater than the maximum number of primary load cases actually used in the model.

SET DISPLACEMENT

i2 For PDELTA ANALYSIS with CONVERGE option there are two convergence methodologies to choose from (refer to TR.37.2 P-Delta Analysis Options for additional information)
  1. The SET DISPLACEMENT i2 command is used to specify the convergence tolerance. If the Euclidean norm RMS displacement of two consecutive iterations changes less than the value entered, then that load case is converged. This command should be placed before the JOINT COORDINATE specification. The default tolerance value, i2 , is equal to the maximum span of structure divided by 120. The convergence tolerance for the Euclidean norm is difficult to know, so using this option is not recommended.
  2. The SET PDELTA TOL i9 command selects this second method. Default tolerance value, i9 , is 0.01 inch. If the maximum change in each displacement dof from two consecutive iterations is less than ftol, then that load case is converged. This command should be placed before the JOINT COORDINATE specification and after a UNIT command.
Note: Both i2 and i9 are the P-Delta Convergence criteria input. There are two methods available, enter SET DISPLACEMENT i2 or SET PDELTA TOL i9 . Enter only one.
  • i2 = If the change in the Euclidean norm of the displacement vector from one PDELTA iteration to the next is less than this convergence tolerance value; then the iteration has converged for the case being analyzed.
  • i9 = If the maximum absolute change in displacement of each dof from one PDELTA iteration to the next is less than this convergence tolerance value; then the iteration has converged for the case being analyzed.

PDELTA TOLERANCE

i9
SET DEFLECTION CUTOFF f1 Used to arrest huge displacements in minor axis due to small delta effects.

f1 = If the absolute value of the maximum section displacement is less than f1 after two iterations; then it is converged. Rapidly diverging minor axis displacement will not occur until after two iterations. f1 is in current length units.

SET FLOOR LOAD TOLERANCE f2

Used to specify the tolerance for out of plane nodes in a floor load. The value is given as a length, in current units. The default is take as 0.01% of the length of the longest beam of the beams in the floor load command.

For example, if a floor group is used, then beams in the floor group are used in the computation. Similarly, when a Y range is used, beams within that range are used.

Refer to TR.32.4.3 Floor Load Specification for details on specifying a plane for floor loads.

f2 = tolerance value used

The following SET commands have dimensionless input

Table 2. Other commonly used SET commands
Command Parameter Description
SET SDAMP i3 The SET SDAMP command will allow the damping of springs to be considered in computing the composite modal damping for each mode in a dynamic solution. This command is not used unless CDAMP ratios are also entered for the members and elements in the CONSTANTS command. Composite damping is generally only used if there are many modes in the dynamic solution and there are a wide range of damping ratios in the springs, members, or elements.

i3 = the damping ratio to be used for all springs in computing the modal composite damping in dynamics.

SET WARP i4 The SET WARP command will allow the I section member end warping restraint to be considered in calculating the torsional stiffness rigidity. Full or partial or no warping restraint are allowed.
SET ITERLIM i5

The SET ITERLIM command is for raising the maximum iteration limit above the default of 10 in tension/compression iterations. Since this iterative procedure will not necessarily converge, this option of more iterations may not help and should be used with caution. The minimum iteration limit that may be entered is 3.

After any tension/compression analysis, the output file (file extension .ANL) should be scanned for warnings of non-convergence. Do not use results from non-converged cases.

i5 = Maximum number of tension/compression iterations.

SET PRINT i7 The following values can be used to suppress the described warnings or include the described additional results in the output:
  • 1 = Omit zero stiffness message, Rotational zero stiffness message due to solids, and "Node not connected. OK if master/slave" message.
  • 2 = Omit Member in list does not exist message.
  • 3 = Omit joint not connected message.
  • 5 = Turn off floor load message.
  • 8 = Omit self weight warnings.
  • 10 = Turns on some iteration messages in direct analysis.
  • 17 = Write rotational masses to mass text file; otherwise only translational masses written. Print scaled modal results for RSA and some force data by floor for RSA.

i7 = Used to suppress some warning messages or to include additional output.

SET NOPRINT DIRECT (n/a) Used to turn off the tau-b details in the output file when running a Direct Analysis (refer to TR.37.5 Direct Analysis).
SET SHEAR (n/a) The SET SHEAR command is for omitting the additional pure shear distortion stiffness terms in forming beam member stiffnesses. With this command you can exactly match simple textbook beam theory results.
SET ECHO (n/a) The SET ECHO ON command will activate and the SET ECHO OFF command will deactivate the echoing of input file commands in the output file. In the absence of the SET ECHO command, input file commands will be echoed back to the output file.
SET GUI i6 After the calculations are completed, and before the Analysis window is closed, the program creates several files for the purpose of displaying results in the post processing mode. In large models, this can be a time consuming process. If the user's goal is to look at results in the output file only (file extension .ANL) and does not intend to go into the post-processing mode, he/she could instruct the program to skip the process of creating those files. The SET GUI 1 may be specified immediately before the FINISH command, or somewhere near the beginning of the file after STAAD SPACE.

i6 = 1, Bypass forming data and files needed for post-processing.

SET { Z | Y } UP (n/a)

By default, the Y-axis is the vertical axis. However, the SET Z UP command may be used to model situations where Z-axis represents the vertical axis (direction of gravity load) of the structure. This situation may arise if the input geometry is created through some CAD software. This command will affect the default BETA angle specification. However, BETA can be set to a certain value for all members parallel to a particular global axis by using the MEMBER X (or Y or Z) type of listing. For additional information, see the CONSTANTs specification (see TR.26 Specifying and Assigning Material Constants).

Note: Both options follow the "right hand rule."

Global axis orientation options in STAAD.Pro

The SET Z UP Command directly influences the values of the following input:
  1. JOINT COORDINATE
  2. Input for the PERFORM ROTATION Command
  3. BETA ANGLE
Note: The following features of STAAD cannot be used with the SET Z UP command:
  • Automatic Generation of Spring Supports for Mat Foundations
SET STAR i Instructs the program which solver to use. Refer to TR.0 STAAD Commands and Input Instructions for additional information.
  • 3 = STAAD Advanced Solver (in-core) - default
  • 4 = STAAD Advanced Solver (out-of-core)
Note: When SET STAR 3 is used and if the following limits are exceeded, then the solver will automatically switch to out-of-core:
  1. Number of nodes >30,000
  2. Number of nodes times the number of active primary load cases > 1,600,000
SET EIGEN METHOD { LANCZOS | RITZ } (n/a)

LANCZOS — Instructs the solver to use Arnoldi/Lanczos method for extraction of eigen vectors.

RITZ — Use load dependent Ritz vectors method for extraction of eigen vectors.

The use of either the Arnoldi/Lanczos method or the Ritz method require a STAAD.Pro Advanced license. If neither method is specified, the default method of Subspace-iteration is used.

Note: SET EIGEN METHOD RITZ is not supported by pushover analysis or steady state analysis. In the case of a pushover analysis, this is because the lateral load distribution is based on the eigen vector. If the command is present, a warning message is given in the output.

Less frequently used SET commands

The following table contains a list of less frequently used SET commands

Command Default Description
SET INTERPOLATION { LIN | LOG }   LIN or LOG for spectra
SET NOSECT   No section results will be calculated
SET PLATE FLATNESS TOLERANCE f  

Used to so specify a tolerance for the plate warping check. By default, plate warping is reported when there is a 30 degree angle (or larger) between the normal to two triangles which are formed by splitting a quad element. This splitting can be done two ways so there are four triangles. If any have more than the tolerance angle (in degrees) between them, then an error is reported.

The value f is given in degrees.

SET INPLANE ROTATION   In-plane rotation (MX) in plates will be ignored.
SET NANGLE    
SET ENDFACTOR f   1.0 or -1.0 for combining spectrum cases
SET PROFILE s2   A command to define the path of the folder that contains the collection of databases of section property data in SQLite (.DB3) files. Note also that the GUI will use this as the location of the section profile databases.
SET NOWARNING   Switches off some warning messages.
SET USE DLL   Used plugin .dll for design (ACI code only)
SET RIGID DIAPHRAGM i 150

The number of diaphragms used. This command is used to reserve memory for the maximum number of diaphragms that may be defined in the model.

See section TR.28.2 Floor Diaphragm for more information on defining and using floor diaphragms in an analysis.
SET INCLINED REACTION   To obtain reactions at inclined supports in the inclined axis system.
SET GROUP DUPLICATES   Followed by an integer value which is used to specify the number of groups to which one model entity (node, member, plate, or solid object) may belong. Must be in the range of four to 100, inclusive. The default value is 10 groups.
SET CG TXT   Used to print section forces for generated load combinations to an external text file. See TR.35 Load Combination Specification for additional details. This command should be used only for review of data and not in normal circumstances as the resulting text file can be very large.
SET RS TXT   Used to print section forces for each of the modes for response spectrum load cases to an external text file. See TR.35 Load Combination Specification for additional details. This command should be used only for review of data and not in normal circumstances as the resulting text file can be very large.
SET NF TXT   Used to print section forces for each member corresponding to the critical load combination generation case to an external text file. See TR.35 Load Combination Specification for additional details. This command should be used only for review of data and not in normal circumstances as the resulting text file can be very large.
SET THCOPYS i  

i = 4 (default)

i = number of TYPES that a given node-dof may be a part of in time history loading.

SET WARNING { ON | OFF }   Used to suppress warnings in the output (.anl) file when set to OFF (ON is default).
SET NOTE { ON | OFF }   Used to suppress notes in the output (.anl) file when set to OFF (ON is default).
SET DIVISION i   Set the number of divisions used in meshing for surfaces (default is 10)
SET MULTI { 1 | 2 }   If multi-linear analysis fails to converge, try entering SET MULTI 2 and re-running.
SET PARTICIPATION FACTOR   Compute participation factors as a numeric value in addition to the percentage of total mass usually displayed.
SET BUCKLING MODES i   Number of buckling modes computed with advanced solver. Default is i= 4.
SET BYPASS { DIS | FOR | EJS | EJF }  

Bypass generating certain outputs for the graphical user interface.

  • DIS = section displacements
  • FOR = section force
  • EJS = plate nodal stress
  • EJF = plate nodal force
SET LOAD PLATE   Include loads applied to inactive plates.