NL link in SAP2000

[gswarup]

Hi,
I am trying to perform a nonlinear modal time history analysis of plane RC frame building (2D frame) in SAP2000 v14. I want to model the frame as concentrated plasticity and for that I tried to use NL Link (Multi linear plastic) at beam ends. My model consists of 3-storey 2-bay frame where top beams are 250mmx300mm and for ground and 1st storey 250x400 and the column sections are 300x300 and loads are provided at joints as joint load. Beams are modeled as Mander unconfined concrete and columns are considered confined with appropriate percentage of reinforcement. To account for PMM interaction fiber hinge is considered at column base (at support location). But I am facing great difficulty to model NL link. I provided a gap equal to d(effective depth of beam) between beam end and respective column joint and connected with 2-joint NL link and chosen Takeda Hysteresis type. But there are more inputs required. I’ve chosen 3 DOF(U1, U3 and R2) and rest left unchecked but what should I put for effective stiffness and effective damping for that particular case? What will be mass and weight of link? what should I put as shear distance for U3 DOF? Does it required to put 3 rotational inertias? If so then how to calculate for this particular problem?
Can anyone help me and suggest if my procedure is right?
Many many thanks.

 

[johnbridge231]

You can have a look at the analysis reference, under the Help menu item, where almost every questions related to the technical background of the program are answered.

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

 

[gswarup]

Thanks johnbridge231.....actually the analysis was showing instability error....when defining link nonlinear property I left unchecked the DOFs u2, r1, r3....but when I fixed them all then analysis completed successfully....

is my procedure right?.....