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D1.B.1.4 Member Selection

STAAD.Pro is capable of performing design operations on specified members. Once an analysis has been performed, the program can select the most economical section (i.e., the lightest section) which fulfills the code requirements for the specified member.

The section selected will be of the same type section as originally designated for the member being designed. A wide flange will be selected to replace a wide flange, etc. Several parameters are available to guide this selection. If the PROFILE parameter is provided, the search for the lightest section is restricted to that profile. Up to three (3) profiles may be provided for any member with a section being selected from each one. Member selection can also be constrained by the parameters DMAX and DMIN which limit the maximum and minimum depth of the members. If the PROFILE parameter is provided for specified members, DMAX or DMIN parameters will be ignored by the program in selecting these members.

Member selection can be performed with all the types of steel sections listed in D1.A.4 Built-in Steel Section Library of this manual. Note that for beams with cover plates, the sizes of the cover plate are kept constant while the beam section is iterated.

Selection of members, whose properties are originally input from a user created table, will be limited to sections in that table.

Member selection cannot be performed on members whose section properties are input as prismatic.

D1.B.1.4.1 Member Selection by Optimization

Steel table properties of an entire structure can be optimized by STAAD.Pro. This optimization method involves the following steps.

  1. CHECK CODE ALL 
  2. Modify the ratios 
  3. SELECT ALL 
  4. PERFORM ANALYSIS 
  5. SELECT ALL 

An additional step of grouping may be performed if the FIXED GROUP and GROUP commands are provided (See TR.50 Group Specification). After the last step, a re-analysis is not automatically performed, so users must ensure that they specify the analysis command following the SELECT OPTIMIZE command.

D1.B.1.4.2 Deflection Check With Steel Design

This facility allows the user to consider deflection as a criteria in the CODE CHECK and MEMBER SELECTION processes. The deflection check may be controlled using the three parameters DJ1, DJ2, and DFF which are described in D1.B.1.2 Design Parameters. Deflection is used in addition to other strength and stability related criteria. The local deflection calculation is based on the latest analysis results.