STAAD.Pro Help

M. To define direct analysis parameters

To define the member parameters used in an AISC 360 direct analysis, use the following procedure.

Note: The yield strength of the steel is taken from the material definition. If the material definition is not provided for a member, then a default value of Fy = 36 ksi is used.
  1. On the Loading ribbon tab, select the Direct Analysis tool in the Define Load Systems group. The Create New Load Items dialog open.
  2. Specify the initial τb value: Members whose flexural stiffness are considered to contribute to the lateral stiffness of the structure will have their flexural stiffness (EI) reduced by 0.8×τb .
    1. Select the FLEX Parameter tab.
    2. Type a FLEX value.
    3. Click Add.
  3. (Optional) Identify any axial members which contribute to the lateral stiffness of the structure:
    1. Select the AXIAL Parameter tab.
    2. Click Add.
  4. Click Close.
  5. In the Load & Definition dialog, expand the Definitions > Direct Analysis Definition group.
  6. Assign each of the FLEX and AXIAL parameters listed to the corresponding members in the model.
You must add one or more load cases with notional loads to your model for a direct analysis.