Applies To 
 Environment: N/A
 Area: STAAD.Pro Analysis
 Subarea: STAAD.Pro Direct Analysis
 Original Author:Bentley Technical Support Group

The AISC 360-16 Specification, Chapter C, specifies that the stability shall be provided for the structure as a whole and for each of its elements. That means the stability needs to be maintained for the individual members, connections, joints and other building elements as well as the structural system as a whole.

The code recommends using any method that ensures the stability of the structure as a whole and for individual building elements and meets with all the following requirements are permitted.

  1. Flexural, shear and axial member deformations and all other deformations that contribute to displacements of the structure.
  2. Second-order effects (both P-∆ and P- Ϩ effects)
  3. Initial geometric imperfections
  4. Stiffness reduction due to inelasticity
  5. Uncertainty in stiffness and strength

The Direct Analysis Method (DAM), as described in the AISC 360-16 Specification, Chapter C (Design for Stability), satisfies all the aforementioned conditions. Use the following resources to learn how the Direct Analysis Method has been implemented into STAAD.Pro:


Frequently Asked Questions (FAQs)

This page contains a list of FAQs related to DIRECT ANALYSIS in STAAD.Pro. Click on the links below to view the details on each topic

  1. Steel and Concrete Structures: How can I analyze a model that contains both steel and concrete elements? I want to use the direct analysis method to analyze the steel structural elements and P-Delta for the concrete elements. Each design will also have their own set of load combinations.
  2. Deflections: In a direct analysis, are the beam deflections for serviceability checks computed using the unreduced E and I values?
  3. Member Tension or Compression: Can I use the Member Tension or Member Compression Specification with a Direct Analysis?
  4. Inactive Members: Can I run a direct analysis with the inactive member specification applied to some members?
  5. FLEX and Tau-B: What is the value that I have to enter for the FLEX parameter? Why does the Tau-b value change from iteration to iteration?
  6. Second Order Drift/First Order Drift: How can I find the second order drift/first order drift ratio using STAAD.Pro?
  7. Iterations: Can you explain the iteration options with the PERFORM DIRECT ANALYSIS command?
  8. DAM and ASD: For a direct analysis using the ASD method, does STAAD automatically factor the loads by 1.6 and divide the results by 1.6?
  9. Response Spectrum Loading: Can I use a response spectrum load case in a Direct Analysis?
  10. FYLD Parameter: Has the FYLD parameter within the Direct Analysis Definition been deprecated?
  11. Benchmark/Example Problems: Do you have any examples of implementing the DAM into STAAD.Pro?
  12. [[How to resolve "Direct PDelta is divergent" errors during direct analysis.]]