Topic: Increased stiffness of system
i am modelling a reinforced concrete beam with ATENA sciene/GiD. It's a simple system: a short single span beam which is loaded centrically by a point load (modelled path controlled by increasing a displacement). All in all it's very similar to the GiD Tutorial.
Now, there is a load-deformation-curve given by experiments and my maximum load by ATENA is very similar to the result of these experiments. But my vertical deformation in the middle of the field is only about 50% of the experiment's deformation.
So my modelled system seems to be much stiffer than in real life. I've checked the geometry and material parameters several times. I've also tested different values for the Young's modulus but the gradient of my F-w-curve is still much bigger than the one of the experiments.
Do you know an input factor in ATENA/GiD that could lead to such a (wrongly) increase in stiffness?