Hello, I'm modeling a shear critical normal strength concrete beam for my final research project. I model a FE beam using Abaqus. and add material models using CDP. but the problem is my model stiffness is much larger than the actual experimental beam. so I deleted the CDP and checked for the elastic region. but the problem is the same. then I model another beam using another experimental data. it also shows a high stiffness.  here I attached the curve I got and the blue color line is the line shoud i get. please help