Non Linear Analysis Load combinations SAP 2000

[Alex786]

Dear Engineers,
I'm new to SAP , Initially i have done analysis on structure using Static Linear Analysis Option with load combinations.
I changed my Analysis Type to Static Non Linear (because i had to model cable in the structure) ,but the Load Combinations do not work and do not reflect the Non Linearity.
My Question to you is , How do we Assign Load Combinations for Non Linear analysis.
Thanks Guys !
Cheers!

 

[johnbridge231]

Linear load combinations are not valid in non linear analysis. You should convert the combination to a non-linear case and run the analysis for this one.

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]

johnbridge is correct. The load combinations need to contain a nonlinear load case. The Define>Load combinations, convert to nonlinear case option is a useful way to achieve this. However, please note that when the convert load combos to nonlinear case option is used, the nonlinear load case is set to nonlinear P-delta. That means that any nonlinear link boundary condition will be considered as well as tension/compression limits and iterative nonlinear P-delta effects. However, if your cables may experience catenary behavior, you may want to change load case(s) to nonlinear P-Delta with large displacements.

The convert (linear) load combinations to nonlinear actually does three things: 1) It takes the loads case components associated with each selected load combo and uses those cases to create a single NL load case. A single NL load case can include multiple load patterns, so it often acts like a load combination. 2) It automatically creates new load combinations with a similar name (adding NL) but with one single nonlinear load case (which again, can include multiple load patterns) in each associated load combination. 3) It automatically places these NL combos in the Design load combinations for design. I don't believe SAP2000 can design based on a load case or load pattern, you must put them within a load combination in order to design