TR.37.1 Linear Elastic Analysis
Used to perform a static, linear elastic analysis on the structure.
General Format
PERFORM ANALYSIS (PRINT { LOAD DATA | STATICS CHECK | STATICS LOAD | BOTH | ALL } )
Without one of these analysis commands, no analysis will
be performed. These
ANALYSIS
commands can be repeated if multiple analyses
are needed at different phases.
PRINT
options are available:
- If the
PRINT LOAD DATA
command is specified, the program will print an interpretation of all the load data. -
PRINT STATICS CHECK
will provide a summation of the applied loads and support reactions as well as a summation of moments of the loads and reactions taken around the origin. -
PRINT STATICS LOAD
prints everything thatPRINT STATICS CHECK
does, plus it prints a summation of all internal and external forces at each joint. This option generates a large volume of output.Note: SincePRINT STATIC LOAD
generates voluminous output, the printing of summation of internal and external forces at each joint is done for structures which have less than 1,000 joints. If the structure has 1,000 joints or more, this printing will be skipped. -
PRINT BOTH
is equivalent toPRINT LOAD DATA
plusPRINT STATICS CHECK
. -
PRINT ALL
is equivalent toPRINT LOAD DATA
plusPRINT STATICS LOAD
. - The
PRINT MODE SHAPES
command may be added separately after the Analysis command if mode shapes are desired. Refer to TR.42 Print Specifications for using additional print specifications.
Notes
This command directs the program to perform the analysis that includes:
-
Checking whether all information is provided for the analysis;
-
Forming the joint stiffness matrix;
-
Checking the stability of the structure;
-
Solving simultaneous equations, and
-
Computing the member forces and displacements.
-
If a
RESPONSE SPECTRUM
,TIME LOAD
, orGROUND MOTION
is specified within a load case or theMODAL CALCULATION
command is used, a dynamic analysis is performed.
General Analysis Comments
STAAD.Pro allows multiple analyses in the same run. Multiple analyses may be used for the following purposes:
-
Successive analysis and design cycles in the same run result in optimized design. STAAD.Pro automatically updates changes in member cross-sectional sizes. Thus the entire process is automated.
Refer to Example 1 in the Getting Started & Examples manual for detailed illustration.
-
Multiple analyses may be used for load-dependent structures. For example, structures with bracing members are analyzed in several steps. The bracing members are assumed to take Tension load only. Thus, they need to be activated and inactivated based on the direction of lateral loading.
The entire process can be modeled in one STAAD.Pro run using multiple
PERFORM ANALYSIS
commands. STAAD.Pro is capable of performing a design based on the load combinations provided.Refer to Example 4 in the Getting Started & Examples manual for detailed illustration.
-
You may also use Multiple Analyses to model change in other characteristics like supports, releases, section properties, etc.
-
Multiple Analyses may require use of additional commands like the
SET NL
command (TR.5 Set Command Specification) and theCHANGE
command. -
Analysis and
CHANGE
are required after UBC cases if the case is subsequently referred to in a Repeat Load command or if the UBC case will be re-solved after a Select command or after a Multiple analysis.