# Shearwall Modeling

**4.5.3. Modeling of Reinforced Concrete Hollow Shearwalls**

**4.5.3.1 -** Reinforced concrete curtains are vertical carrier system elements that generally work as *cantilevers* .

**4.5.3.2 -** Rectangular reinforced concrete walls are structural system elements defined as at least * 6* (six) ratio of length in section to thickness .

**4.5.3.3 - In** reinforced concrete walls with cross-section shape I, T, L, U or C, at least one wall arm in each direction will meet the condition given in **4.5.3.2** . Otherwise, the carrier system element will not be counted as a curtain in that direction. However, the condition given in **4.5.3.2** may not be applied in case of a curtain arm (or parts) of a *tie-beam curtain* that **meets 4.5.4.5 of the** curtain arm (or arms) in I, T, L, U or C section walls .

**4.5.3.4 - ***Shear frame* models in which the *wall end regions* defined for the reinforced concrete design of the wall section in **Chapter 7** are modeled like a column, and the body region between them as a very rigid beam, will not be used for walls.

**4.5.3.5 -** Modeling techniques in which curtain arms are modeled and calculated separately for walls with cross-section shape T, L, U or C shall not be used for curtains .

**4.5.3.6 -** Reinforced concrete walls **will** be modeled by one of the methods given in **4.5.3.7** and **4.5.3.8** .

**4.5.3.7 -** Reinforced concrete walls with rectangular cross-section shape I, T, L, U or C shall be modeled with *shell finite elements* containing degrees of freedom for both in-plane and out-of-plane displacements .

**(a) ** All 6 degrees of freedom shall be considered at the joints of shell finite elements.

**(b) ** Finite element dimensions shall be chosen in such a way that the internal force distribution is calculated with sufficient accuracy.

**(c) ***Effective cross-section stiffnesses* for in-plane and out-of-plane behavior shall be determined in accordance with **4.5.8** .

**(d) For** walls with rectangular cross-section shape, I, T, L, U or C, the resultant of the forces of the finite element node, the *equivalent rod cross-section effects* at the cross-section gravity center (bending / torsion moments, shear forces, axial force), based on the reinforced concrete section calculation. ) will be obtained as. The bending moment obtained in this way at the wall *base shall* be used as the curtain *base overturning moment M *

**in**

_{DEV}**4.3.4.5**,

**4.3.4.6**and

**4.3.4.7**.

**4.5.3.8 - Walls with a** rectangular cross-section shape, I, T, L, U or C, can be modeled as an *equivalent rod* finite element whose axis passes through the center of cross-section gravity, where the ratio of the largest curtain arm length to the total wall height in the plan does not exceed 1/2 . In this case;

**(a) The ***dependent* degrees of freedom at the joints of the wall pieces at the floor levels with the beam and / or slab finite elements in the plan shall be connected *kinematically* to the 6 *independent* degrees of freedom at the *main node,* which will be defined at the cross-section gravity center, in a way to provide the *three-dimensional rigid body motion* condition .

**(b) ***Effective cross-section stiffness* for bending and shear of walls modeled as equivalent bars shall be determined according to **4.5.8** .

**(c) ** Based on the reinforced concrete section calculation, the rod section effects (bending / torsion moments, shear forces, axial force) are obtained directly at the section center of gravity. The bending moment obtained at the wall *base will* be used as the curtain *base overturning moment M *_{DEV} in **4.3.4.5** , **4.3.4.6** and **4.3.4.7** .