It is common for FE models to produce stiffer results compared to experimental data. However, if you want to reduce the initial stiffness, you can introduce some nonlinearity at the boundary conditions (B.C.). For instance, in reality, a fixed condition is rarely perfectly fixed—there are usually small gaps and loosening that allow for slight rotations and movements. In FE analysis, these effects are typically neglected due to the assumed rigid constraints.

To account for this, you can define nonlinear springs with high stiffness values at the relevant boundary conditions. This approach will allow some flexibility, helping to better capture the real behavior of the structure and reduce the initial stiffness in your model.

Additionally you can also make sure of elastic modulus that you have assigned your concrete.

Kind regards,

Nima

@Nima Kian Thankyou sir.

It is known that to reduce stiffness at the elastic stage in ABAQUS, you can:

1. Lower Young’s modulus to reduce material stiffness.

2. Apply a softening parameter in the material model.

3. Ensure appropriate boundary conditions to avoid over-constraining.

4. Use nonlinear material models if applicable.

5. Refine the mesh to capture more flexible behavior.

These adjustments can help achieve more realistic elastic responses in your FE analysis.

@Hasan Altawil Thankyou sir