Seismosoft | Earthquake Engineering Solutions

Hi,
I have implemented a infill frame model in Seismostruct v5.2. I did a static time history with displacement imposed, and the results was very weird. In the Strut response the maximum compressione force is 36 kN, then I suppose that the stress is F/A with A=strut Area A1 (0.101 m2), that is 356 kN/m2 = 0.356 MPa, but in the model I put 1.2 MPa!!
Also in the shear response the values aren't the same. Furthermore if i change the parameter in the shear curve (inf_shear) example: tau0 (shear bond stress) , or reduction shear factor, the result are always the same. It is absurd!
I ask me if the model that was done in Seismostruct is wrong or I have wrong something.
Excuse for my English.

GHM, hi.

As you will notice from reading the Help System:

- two internal struts are used in each direction (from the total of four struts in the model), hence, in order to assess the compression force carried out by the infill strut, you should sum the compression force values observed in the two struts in the same direction. In other words, the maximum strut force developed in your model is not 36kN, but rather 2x36=72 kN

- the compression force carried out by the infill depends on the equivalent compression strut area. So, if you set 'Strut Area 2' equal to 100% of 'Strut Area 1', so as to have no reduction of the equivalent strut area due to cracking/damage, then you will realise that the maximum compression force developed in your model is 2x60=120 kN, in correspondance to the 1.2 MPa capacity that you had defined.

- the 'shear bond strength' may indeed not have an immediately visible impact in the capacity of the infill, which tends to be instead dictated by the 'maximum shear resistance'. The same may occur with the 'reduction shear factor'.

Please do pay a read of the literature indicated in the Help System, for further details on the working of this model.

Seismosoft Support

Thank you so much for the response!