DAM parameters

Notional horizontal forces

By default, notional loads can be generated along the positive and negative directions for X and Y.

For each combination, the program identifies horizontal forces, and generates the appropriate notional loads to compensate these forces.

Notional loads can be added to the combination in three ways:

• In the direction of the lateral load
  

  (a) The notional loads (NL1) are aligned with the acting lateral load (blue arrow).

  Note: The sum of all horizontal forces determines the direction of the lateral load.
• In one active direction only
  

  (b) Notional loads (NL1) are added in the direction which is closest to the lateral load (blue arrow).

• In two active directions independently
  

  (c) If the sum of horizontal forces determines that the lateral load (blue arrow) acts between the X and Y directions, then notional loads (NL1 and NL2) are created on both axes.

If a combination does not include horizontal forces, then for each of the positive and negative directions of X and Y, the program creates a copy of this combination with the adequate notional loads.

You can change the direction of the notional horizontal forces, and the gravity load multiplier in the Direct Analysis Method Parameters dialog.

Stiffness reduction

The appropriate Young's modulus is used to reduce the element thickness.

By default, restrictions apply with the ANSI/AISC 360-10 code, but user-defined values can be changed freely.

Second-order analysis (P-Delta analysis)

Because the P-Delta analysis is a nonlinear analysis, the load combinations are processed independently.

Click Second-order analysis parameters in the Direct Analysis Method Parameters dialog to modify the analysis parameters.