# Column Shear Design Forces

Cutting safety control of the columns is done automatically.

Shear force

*V*_{e to}be taken as basis for transverse reinforcement calculation in columns ,**Eq. It**is calculated automatically with**(7.5)**.

**For**the calculation of*M*_{a}and*M*_{u}in**Eq. (7.5)**,**7.3.7.2**is applied automatically at the lower and / or upper ends of the column, if**Equation (7.3)**is fulfilled , and**7.3.7.3 is**automatically applied if it is not .

The sum of the shear force calculated from the earthquake increased with

*D*with the vertical loads ,**Eq. If***V*_{e}calculated by**(7.5)**is smaller than*V*_{e}, this shear force is used instead of*V*_{e}condition is applied automatically.

**Equation (7.6)**is applied separately for both directions of the earthquake and the largest ∑*M*_{p}value obtained in each direction is taken as the basis in the distribution.**Eq. (7.3)**'s achieved even though the**Eq. (7.5)**' one of*M*_{a}or*M*_{ü}'are account**7.3.7.3**According done automatically.

*In the*calculation of*M*_{pa}and*M*_{pü}moments,*N*_{d}axial forces which make these moments maximum in accordance with the direction of the earthquake are taken into consideration.

Moment

*M*_{a}at the lower end of columns connected to the**foundation**is automatically calculated as moment capacities according to**7.3.7.3**.

**The**shear force calculated by**Equation (7.5)**,*V*_{e}, the shear force calculated under the combined effect of vertical loads and earthquake loads multiplied by the load coefficients, is not taken less than*V*_{d}and it is also automatically checked whether it meets the conditions given in**Eq. (7.7)**.

**In the**calculation of the transverse reinforcement in the column confinement zones defined in**7.3.4.1**, if the shear force consisting only of seismic loads is greater than half of the total shear force in seismic condition and at the same time, the condition of*N*_{d}≤ 0.05*A*_{c}f_{ck is}fulfilled, the contribution of the concrete to the shear strength*V*_{c}= 0 is taken.

**ICONS**

**A _{w }=** Effective body area of column cross-section

**f**Characteristic cylinder compressive strength of concrete

_{ck}=**f**Design compressive strength of concrete

_{cd}=**f**Design yield strength of longitudinal reinforcement

_{yd}=**L**Free height of column between beams, free span of beam between column or curtain faces

_{n }=**M**Moment at the lower end of the column's free height, based on the column shear calculation

_{a }=**M**At the upper end of the column's free height, the moment

_{ü }=**M**moment at the upper end of the column is the moment at the work floor.

_{hü (i) }= The**M**is the moment at the lower end of the column at the work floor.

_{ha (i) }= It**M**is the moment at the lower end of the column in the upper floor of the studied floor.

_{ha (i + 1)}= It**M**the moment at the upper end of the column in the lower floor of the studied floor.

_{hü (i-1)}= It is**M**The moment of bearing strength calculated according to f

_{ra}=_{cd}and f

_{yd}at the lower end of the free height of the column or curtain

**M**The moment of bearing strength calculated according to f

_{rü}=_{cd}and f

_{yd}at the upper end of the free height of the column or curtain

**M**The moment of positive or negative bearing strength calculated according to f

_{ri}=_{cd}and f

_{yd}on the column or wall face at the left end i of the beam

**M**Negative or positive moment of bearing strength calculated according to f

_{rj}=_{cd}and f

_{yd}on the column or wall face at the right end j of the beam

**V**Contribution of the concrete to the shear strength

_{c }=**V**Shear force based on column transverse reinforcement calculation

_{e }=**Shear force to be based on transverse reinforcement calculation**

**7.3.7.1 -** Shear force *V *_{e to} be taken as basis for transverse reinforcement calculation in columns , **Eq. It** is calculated by **(7.5)** .

*V *_{e} = ( *M *_{a} + M _{ü} ) **/** L _{n } **(7.5)**

It is important for the calculation of M _{a} and M _{ü} whether the sum of the bearing strength moments of the columns at the node point is 20% more than the moments of the beams in both directions of the earthquake . For this reason, it is first checked whether the equation **Equation (7.3)** is fulfilled.

( *M *_{ra} + *M *_{rü} ) ≥ 1.2 ( *M *_{ri} + *M *_{rj} ) **(7.3)**

**In case Eq. (7.3)** is not provided:

The sum of the torque capacity of the joint at the ends of beams Σ *M *_{p} torque **Eq. (7.6)** is calculated by.

∑ *M *_{p }**= ***M *_{pi} + *M *_{pj } **(7.6)**

*M *_{pa} ≈1.4 *M *_{ra} and *M *_{pi} ≈1.4 *M *_{r} can be taken. *In the* calculation of *M *_{pa} and *M *_{pü} moments, *N *_{d} axial forces which make these moments maximum in accordance with the direction of the earthquake are taken into consideration.

#### M _{u} 's account:

#### Calculation of M _{a} :

**In case Equation (7.3)** is met:

The moments calculated at the ends of the columns joining the node point are accepted as the moment capacities of the columns **. (7.5)** 't *M *_{a} and / or *M *_{ü} used instead.

*M *_{pa} ≈1.4 *M *_{ra} and *M *_{pi} ≈1.4 *M *_{r} can be taken.

#### M _{u} 's account:

#### Calculation of M _{a} :

Moment *M *_{a} at the lower end of columns connected to the foundation is also used as moment capacities.

### V _{e} 's account:

After determining M _{a} and M _{u} , Ln is calculated by considering column clear height.

*V *_{e} = ( *M *_{a} + M _{ü} ) **/** l _{n } **(7.5)**

**The** shear force calculated by **Equation (7.5)** , *V *_{e} , the vertical loads multiplied by the load factors and the shear force calculated under the combined effect of earthquake loads shall not be taken less than *V *_{d} .

And> = Vd.

And it must satisfy the conditions given by **Equation (7.7)** . If it cannot be achieved, the earthquake calculation should be repeated by increasing the column section dimensions as necessary.

Vr is the shear strength of the column section _{. }It is calculated with the following steps according to **TS500 .**

As stated in **TBDY 7.3.7.6** , in the calculation of transverse reinforcement in the column confinement zones, the contribution of concrete to the shear strength is V if the shear force consisting only of earthquake loads is greater than half of the total shear force in earthquake condition and at the same time the condition N _{d} <0.05A _{c} f _{ck is met. c} = 0 is taken.