Shear wall - slab connections

[johannvdm]

To model a frame with columns, slabs and a shear wall I understand that one will have to model rigid lever arms from the centre line of the shear wall being modelled and the slab elements on both sides of the shear wall to obtain the correct displacement of the slab next to the shear wall. These lever arms will have to be weightless and very stiff.

When analysed, the Max_Tol is exceeded in the permanent load phase. Could this be because there is a problem with the weightless lever arm elements?

[seismosoft]

Hi. The modelling approach you describe is correct. There could be multiple causes for a Max_Tol problem, one of which being an excessive stiffness of the rigid lever arms (as discussed in the Help System, the solver will consider elements as infinitely rigid if their stiffness is 100-250 times that of adjacent elements). If this is not what is causing the problem, then another possibility could be an excessive gravity load level. Do give it a go and then let us know.
Hint: try running an eigenvalue analysis first, to make sure that all elements are correctly connected to one and other.

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[johannvdm]

Hallo. Thank you very much. The analysis ran when I lowered the E value of the lever arms. I have connected concrete elements (material con_cc) with a lever arm with an elastic material (el_mat) chosen. No E value is assigned to the concrete material but is assigned to the reinforcing steel in the concrete sections. I have chosen the E-value of the lever arm as 250 times greater than that assigned to the reinforcing steel. Does that sound like the right approach?

[seismosoft]

The initial uncracked concrete Young Modulus is computed as described in the Help System (see eigenvalue analysis section, or refer to the original publication of this model).
To estimate the stiffness of your members, simply use one of the many classical expressions available (e.g. k=12EI/l^3 for a beam/column under double-bending).

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