# Conditions for Columns to be Stronger than Beams (Strong columns)

The condition that columns are stronger than beams is automatically controlled according to

**Equation 7.3**.

**Equation 7.3**is applied separately for each earthquake direction and for both directions of the earthquake, giving an unfavorable result.

All of the columns joining the node point

*N*_{d}≤ 0.10*A*automatically controlled._{c}f_{ck are}

**ICONS**

**A _{c} =** Cross-sectional area of the column

**f**Characteristic compressive strength of concrete

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

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

_{yd}=**M**Bearing strength calculated according to f

_{ra}=_{cd}and f

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

**M**column or in the upper end of the free height of the curtain for

_{r}=_{CDs}and f

_{yd}'calculated according to the ultimate moment

**M**Moment of positive or negative bearing capacity calculated according to f

_{r}=_{cd}and f

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

**M**Negative calculated according to f

_{rj}=_{cd}and f

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

**N**Axial force calculated under the combined effect of vertical loads and earthquake loads multiplied by the load factors.

_{d}=**V**Sum of shear forces calculated in the direction of the earthquake in all columns on the i'th floor of the building

_{ik}=**V**The sum of shear forces calculated in the direction of the earthquake considered in the columns where (M

_{is}=_{ra}+ M

_{rü}) ≥ 1.2 (M

_{ri}+ M

_{rj}) is provided at both the lower and upper joints of the building.

*At the*ends of the columns

_{meeting the}condition

*N*

_{d}≤ 0.10

*A*

_{c}f

_{ck},

**Eq.**Even if

**(7.3)**is not provided, these columns are also not taken into account in the calculation of

*V*

_{is}.

### Conditions for Columns to be Stronger than Beams (Strong columns)

The sum of the moments of bearing strength of the columns is considered to be 20% more than the moments of the beams for both directions of the earthquake **(Equation 7.3).**

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

However, whether **Equation 7.3** is fulfilled is exempted for the following conditions:

If

*N*_{d}≤ 0.10*Ac f*ck is achieved in both columns joining the node pointIn single-storey buildings and at the nodes of columns that do not continue to the upper floor of multi-storey buildings

In case the curtain where the beams are stuck working like a column in the weak direction

**It** is considered to be stronger than column beams when **equation 7.3 is** satisfied or when the exemption conditions are met.

### The situation that the columns are not stronger than the beams (Weak column)

Columns are considered to be weaker than beams when **(Equation 7.3) is** not fulfilled and exemption conditions are not met.

The following steps are applied for weak columns:

**The**validity of**Equation (7.4)**is checked.**Provided that Equation (7.4)**is fulfilled , it may be allowed that**Equation (7.3)**is not provided at some nodes above and / or below the relevant floor .

α _{i} = *V *_{is} / V _{ik} ≥ 0.70 **(7.4)**

0.70 ≤ α

_{i}≤ 1.0 interval,**Eq. The**bending moments and shear forces acting on the columns where**(7.3) is provided at**both the lower and upper joints are multiplied by the ratio (1**/**αi).If

**Equation (7.4)**is not**met for**any floor , the structure should be considered as a*frame*with*limited ductility level in*cases where the*ductility level*can be accepted as*frame*, or mixed systems of ductility level can be used in combination with walls with high ductility level or strong column by increasing the system rigidity. conditions must be met.

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