STAAD.Pro SELECT Command Explained with Examples

 

The STAAD.Pro SELECT command is used during steel design to perform member selection. It instructs STAAD.Pro to evaluate specified members using the results of the most recent analysis and select an appropriate steel section that satisfies the applicable design requirements.

This is an important distinction: SELECT is not simply a command for selecting members graphically in the STAAD.Pro interface. In the STAAD input language, SELECT is primarily associated with steel member selection/design. Bentley's technical documentation describes SELECT MEMBER as an operation that selects member sections based on design parameters and the applicable design code. (p.urbanpro.com)

This article explains the STAAD.Pro SELECT command syntax, selection rules, practical examples, relationship with analysis and design, and common limitations.

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1. What Is the STAAD.Pro SELECT Command?

In a typical STAAD.Pro steel design workflow, you may initially assign a trial steel section to members.

For example:

MEMBER PROPERTY
1 TO 20 TABLE ST W12X26

After analysis and design parameters have been defined, STAAD.Pro can be instructed to select a suitable section for the members:

SELECT MEMBER 1 TO 20

STAAD.Pro uses the results from the most recent analysis and the applicable design parameters to perform the selection. The program works through suitable sections and selects a section satisfying the specified design requirements. (p.urbanpro.com)

So the basic idea is:

Trial section → Analysis → Design parameters → SELECT → New selected section

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2. Basic STAAD.Pro SELECT Syntax

The basic syntax is:

SELECT MEMBER member-list

For example:

SELECT MEMBER 1 TO 10

This instructs STAAD.Pro to perform member selection for members 1 through 10.

The command can also be written in abbreviated form:

SELECT MEMB 1 TO 10

According to the STAAD.Pro technical reference, the general format allows:

SELECT MEMBER memb-list
SELECT ALL
SELECT group-name
SELECT PMEMB pmember-list

The MEMBER, ALL, or PMEMB keyword is important; SELECT by itself is not sufficient for the member-selection operation. (p.urbanpro.com)

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3. SELECT MEMBER Example

Consider a simple steel structure with 20 members.

Suppose members 1 to 12 are beams and members 13 to 20 are columns.

You can perform selection separately:

SELECT MEMBER 1 TO 12
SELECT MEMBER 13 TO 20

Or select all members:

SELECT ALL

The first approach gives you more control over which members undergo selection.

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4. Using SELECT with a GROUP

This is where the GROUP command discussed in the previous article becomes useful.

Suppose you have defined:

START GROUP DEFINITION

MEMBER
_COLUMNS 1 TO 20
_BEAMS 21 TO 60

END GROUP DEFINITION

You can then use the group name in a SELECT command:

SELECT _COLUMNS

or:

SELECT _BEAMS

This avoids repeatedly entering long member lists.

This is one of the practical reasons for using meaningful member groups in large STAAD.Pro models. The technical reference explicitly supports group names as an option in member selection. (p.urbanpro.com)

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5. SELECT ALL

If you want STAAD.Pro to perform member selection for all applicable members, you can use:

SELECT ALL

For example:

PARAMETER 1
CODE AISC UNIFIED 2016
TRACK 2.0 ALL
SELECT ALL

The exact design parameters and code depend on the project and selected design standard.

SELECT ALL is convenient for a complete design operation, but it should not be used blindly. You need to understand which members are intended to be designed and whether all members have appropriate section types and design parameters.

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6. SELECT and the Analysis Results

One of the most important points about SELECT is that member selection depends on analysis results.

The normal workflow is:

PERFORM ANALYSIS

PARAMETER
...
CHECK CODE

SELECT MEMBER ...

The technical reference states that member selection can only be performed after an analysis has been carried out. The selection uses the results of the most recent analysis. (p.urbanpro.com)

A simplified workflow is:

MODEL
   ↓
MEMBER PROPERTY
   ↓
LOADS
   ↓
PERFORM ANALYSIS
   ↓
DESIGN PARAMETERS
   ↓
SELECT MEMBER
   ↓
New section selected

This sequence matters because the design engine needs the member forces and other relevant results generated by the analysis.

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7. SELECT vs CHECK CODE

SELECT and CHECK CODE are not the same operation.

CHECK CODE

A code check evaluates the currently assigned member section against the applicable design requirements.

For example:

CHECK CODE ALL

The existing section is checked.

SELECT

The SELECT command attempts to find a suitable section based on the design requirements:

SELECT MEMBER 1 TO 20

In simplified terms:

CHECK CODE → "Does my current section pass?"

SELECT → "What suitable section should I use?"

This distinction is fundamental when interpreting STAAD.Pro steel design results.

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8. How STAAD.Pro Performs Member Selection

The selection process uses the member forces obtained from the most recent analysis and checks potential sections against the applicable design requirements.

Bentley's documentation describes the process as starting with the members in the specified selection list, gathering forces from the latest analysis for the load cases included through LOAD LIST, and then evaluating suitable sections. (Bentley Systems)

Therefore, LOAD LIST can be important when controlling which load cases are considered during the design operation.

A simplified conceptual sequence is:

Latest Analysis Results
        ↓
Load Cases Used for Design
        ↓
Design Parameters
        ↓
Candidate Sections
        ↓
Design Checks
        ↓
Suitable Section

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9. Example with Steel Design Parameters

A simplified example could look like:

PARAMETER 1
CODE AISC UNIFIED 2016
FYLD 345000 MEMB 1 TO 20
TRACK 2.0 MEMB 1 TO 20

CHECK CODE MEMB 1 TO 20
SELECT MEMBER 1 TO 20

The exact parameter values and design code should be selected according to the project requirements.

The important point is that the SELECT MEMBER command is part of the steel design workflow, not a replacement for structural analysis.

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10. SELECT and GROUP — Practical Example

Suppose a building has:

• Members 1–24 → columns

• Members 25–80 → beams

• Members 81–110 → bracing

Define the groups:

START GROUP DEFINITION

MEMBER
_COLUMNS 1 TO 24
_BEAMS 25 TO 80
_BRACING 81 TO 110

END GROUP DEFINITION

You could then use:

SELECT _COLUMNS
SELECT _BEAMS
SELECT _BRACING

This makes the design input considerably easier to read.

Instead of:

SELECT MEMBER 25 TO 80

the group name communicates the engineering purpose:

SELECT _BEAMS

That becomes particularly useful when the model contains hundreds or thousands of members.

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11. SELECT Optimized

STAAD.Pro also provides an optimized member-selection operation:

SELECT OPTIMIZED

This is different from a normal:

SELECT MEMBER ...

The technical reference describes SELECT OPTIMIZED as an optimization-based member-selection process that performs additional analysis/design iterations to reduce structural weight. (SKYSCRAPERS)

Because this process can involve additional analysis and iteration, it can take longer than ordinary member selection.

Therefore, don't assume:

SELECT OPTIMIZED

is simply a faster or "better" version of:

SELECT MEMBER

It is a different design-selection approach.

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12. What Happens After SELECT Changes the Section?

This is one of the most important practical issues.

When STAAD.Pro selects a new member section, the stiffness of the structure can change.

For example, suppose the initial model contains:

W12X26

for a beam.

After selection, STAAD.Pro might assign a different section.

That new section can have different:

• Area

• Moment of inertia

• Torsional properties

• Stiffness

• Weight

Consequently, the structural force distribution may change.

Therefore, after member sizes are changed through selection, a subsequent analysis is normally required to obtain results corresponding to the final member properties. Bentley's documentation specifically notes this requirement. (device.report)

A practical workflow is therefore:

Initial Model
      ↓
PERFORM ANALYSIS
      ↓
SELECT MEMBER
      ↓
New Sections
      ↓
PERFORM ANALYSIS
      ↓
CHECK CODE
      ↓
Review Final Results

Don't stop immediately after seeing that the selected sections pass the initial design check.

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13. Common Mistakes with SELECT

Mistake 1 — Using SELECT Before Analysis

Incorrect workflow:

SELECT MEMBER 1 TO 20
PERFORM ANALYSIS

The member-selection operation needs analysis results.

A more appropriate sequence is:

PERFORM ANALYSIS
SELECT MEMBER 1 TO 20

The technical reference explicitly states that member selection is performed after analysis. (p.urbanpro.com)

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Mistake 2 — Thinking SELECT Means Graphical Selection

STAAD.Pro has many graphical selection tools in the CONNECT Edition interface.

However:

SELECT MEMBER

in the STAAD input file refers to member selection for design.

It is not simply the same thing as clicking members in the graphical interface. STAAD.Pro's user manual separately describes graphical selection modes and tools. (studylib.net)

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Mistake 3 — Forgetting That Selection Changes the Model

A selected section can change the structural stiffness.

Therefore, don't treat the SELECT result as the final answer without performing the necessary subsequent analysis and final design verification.

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Mistake 4 — Selecting Every Member Blindly

Using:

SELECT ALL

is convenient, but not necessarily appropriate for every model.

Some members may require:

• Specific sections

• Special design parameters

• User-defined sections

• Different design treatment

• No automatic selection

The selection list should therefore reflect the intended design strategy.

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14. SELECT Command vs GROUP Command

Because these two commands are being covered together in our STAAD.Pro article series, the distinction is worth remembering.

GROUP

Creates a named collection:

START GROUP DEFINITION

MEMBER
_BEAMS 21 TO 50

END GROUP DEFINITION

SELECT

Performs member selection:

SELECT _BEAMS

So:

GROUP organizes members; SELECT performs member selection for design.

They can work together, but they serve different purposes.

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15. Quick STAAD.Pro SELECT Reference

Command	Purpose
SELECT MEMBER 1 TO 10	Select specified members for member selection
SELECT MEMB 1 TO 10	Abbreviated form
SELECT ALL	Select all applicable members
SELECT _BEAMS	Select members identified by a group
SELECT PMEMB ...	Select physical members
SELECT OPTIMIZED	Perform optimization-based member selection

The precise behavior depends on the design code, member type, section database and design parameters being used. (p.urbanpro.com)

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Conclusion

The STAAD.Pro SELECT command is a steel-design command used to perform member section selection based on the results of the most recent analysis and the applicable design requirements.

The basic syntax is:

SELECT MEMBER member-list

For example:

SELECT MEMBER 1 TO 20

or:

SELECT ALL

A particularly useful approach for larger models is combining SELECT with named groups:

SELECT _COLUMNS
SELECT _BEAMS

The most important thing to remember is that SELECT is not merely a member-selection tool. It is part of STAAD.Pro's steel member-selection/design process.

Also, because selecting a new section can change structural stiffness, the selected sections should be followed by an appropriate re-analysis and final code check before treating the design as complete. (device.report)

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