The axial force in the member will be known only after analysis. So what I suppose you mean to say perhaps may be that you do not want to account for axial force in the design. Please. therefore clarify your query.
Is it for all load cases or just some specific load cases? For example, for gravity loads, if you force all columns to have no axial load resisting ability, how do you expect the load to reach the supports?
If the objective is to remove the axial capacity of just a few specific members such as a few beams, you could either release FX at one end of the member, or, use the feature called PROPERTY REDUCTION FACTOR (section 5.20.10 of the Technical Reference manual). You could set the RAX term to a small number such as 0.05. It will not completely remove the effect, but reduce it to a small value.
MEMBER CRACKED
member-list REDUCTION RAX 0.05
Dear Lose,
What I feel that Staadpro does not at all consider axial force while designing beam. Is it o k? If not. post your comments
Are you talking about concrete or steel members?
For steel members, as the interaction equations indicate, the ratio includes the contribution from the axial effect plus the bi-axial bending effect.
For concrete, when you specify DESIGN BEAM in the STAAD file, axial effect is considered only in some codes implemented in STAAD, that too, just during shear and torsion design. However, if the command is DESIGN COLUMN, axial effect is considered.
Here is a clarification: I analyzed an indeterminate frame structure by consistent deformation method by hand calculations and I neglected the axial deformation in calculating the redundant. STAAD PRO results differ from the hand calculations due to taking in consideration the axial deformation. For checking my hand calculations, I need to tell STAAD PRO to neglect the axial deformations when analyzing the structure to get the reactions. How to do this.
I know that considering the axial deformation gives more accurate results, but I want to neglect it.
Since axial deformation is obtained from the expression Delta = PL/AE, you could set A (Cross section area) for the desired members to a very large value which will then ensure that the axial deformation of those members is small.
If you are specifying the properties through the GUI, go to the General-Property page, choose Define followed by General from the right side of the screen, and fill in the proper values for IX, IY and IZ, and a large value for AX.
If you prefer typing them in the editor, the property type should be PRISMATIC, and values for AX, IX, IY and IZ should be provided as suggested above. You can refer to example problem 8 for a guideline.
SKLose, thanks a lot. I have checked it and it works.