mass eccentericity

[nimaemo1]

hi
i want to make a structure with assymetric plan by moving mass center. how can i do that?
yo know if sap does it right, torsinal mode and tansitional mode should be coupled.
but in my model, with diaphragm eccentericity , these modes arent coupled.

 

[johnbridge231]

What do you mean 'by moving mass center' ?
SAP automatically calculates the mass center according to the diaphragms in your model.

Analysis and Design of arbitrary cross sections
Reinforcement design to all major codes
Moment Curvature analysis

http://www.engissol.com/cross-section-analysis-design.html

 

[stressed]

nimaemo, I'm assuming that you're trying to comply with building code requirements regarding accidental torsional loading

With rigid diaphragm: Add eccentricity as a separate static load case. The response spectrum and eccentric load cases should then be combined with combos using eccentricity in + and - direction. Separate static cases must be run for each eccentricity considered.

With flexible or semi-rigid diaphragm: You can add accidental torsion without rigid diaphragms if you spread/distribute the torsional loading.