Dear Kay Guanlao ,

I am afraid that I could understand your first question well. Which points are you talking about to input manually?

For your second general question. There are many ways to implement in your analytical model to predict cyclic behavior of your specimens in a true way. For instance, to take into account pinching stemming from strain penetration in anchored reinforcements, you may either use the available bond-slip models in OpenSees or utilize a zero-length spring. For the fomer Bond SP01 could be used. For the later one, moment-rotation curve could be inputted as Pinching4 Material available in Opensees. The rotation values stemmed from slip could be obtained via either strain gauge data or moment-curvature analysis.

For the contribution of the shear deformations in top displacement value of your specimen. First you need to make sure if the shear deformations were governed in your case. If so, there are several models allowing shear-flexure interaction consideration in OpenSees, either coupled or uncoupled. SFI MVLEM, and MVLEM are two popular model in this matter.

I hope these help you. If you need more information please ask your questions somehow more specific rather than general. I write here several articles that may help you.

1- Numerical Simulation of FRP-Jacketed RC Columns Subjected to Cyclic and Seismic Loading

2- Numerical Simulation of FRP-Jacketed RC Columns Subjected to Cyclic and Seismic Loading

3- Fiber element modeling for seismic performance of bridge columns made of concrete-filled FRP tubes

4- Effect of ECC jackets for enhancing the lateral cyclic behavior of RC bridge columns

5- Strain penetration effect on cyclic response of corroded RC columns

6- Cyclic shear displacement model for reinforced concrete columns

7- A computational model for reinforced concrete members confined with fiber reinforced polymer lamina: Implementation and experimental validation

8-Experimental research and finite element analysis on the seismic behavior of CFRP-strengthened severely seismic-damaged RC columns

9- CYCLIC BEHAVIOR MODELING OF RECTANGULAR RC BRIDGE PIERS USING OPENSEES

10- Cyclic Testing and Assessment of Columns Containing Recycled Concrete Debris

11-Seismic assessment of non‑engineered reinforced concrete columns in low to moderate seismic regions

12- Finite element analysis on concrete filled steel tubular concrete beam joints under cyclic loading by OPENSEES

13- Modeling of strain penetration effects in fiber-based analysis of reinforced concrete structures

Kind Regards,

Nima Kian

Thank you so much Nima Kian

In my first question, I am pertaining to the points on my envelope curve such as s1p and e1p, s2p and e2p etc. I am still not sure how I can obtain those values.

I attached a picture of my experimental cyclic stress-strain curve of my coupler. I will be modelling my coupler ( connector of rebar ) on Opensees but I am still not sure what type of uniaxial mat is best, that can match my experimental data. I'm planning to use the backbone curve of my experimental cyclic data for my analysis since I will be doing a static pushover analysis.