# Base Shear Scale Factor

**4.8.4. Amplification of Reduced Internal Forces and Displacements According to Equivalent Base Shear Force**

**4.8.4.1 - In case ***V *_{tx }^{(X)} <E * *V *_{tE }^{(X)} for any earthquake direction ^{(X)} , all reduced internal force obtained by the modal calculation method applied according to **4.8.2** or **4.8.3** and The displacement magnitudes will be enlarged by multiplying the *equivalent base shear amplification coefficient* β _{tE }^{(X)} given by **Eq (4.31)** .

Wherein *V *_{t }^{(X)} to the lateral force Method according to **Eq. (4.21)** calculated by the *total equivalent seismic load* (base shear force), *V *_{tx }^{(X)} is **4.8.2** or **4.8.3** according *x direction* 'in It shows the *total earthquake load* obtained . γ _{The} factor of _{E} will be taken as follows:

**(a) If** at least one of the **A1** , **B2** or **B3** type irregularities defined in **Table 3.6** is present in the building, γ _{E} = 0.90 shall be taken.

**(b) If** none of the irregularities defined in **Table 3.6** are present in the building, γ _{E} = 0.80 shall be taken.

**According to** the definition given in **4.8.4.2 - 3.3.1** , in buildings with externally rigid walls surrounded by basements, the *equivalent base shear force amplification coefficient* shall be *calculated* only for the *upper part* above the basement floors of the building .

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