# Determination of Earthquake Performance of Existing Buildings

**15.8. DETERMINING THE EARTHQUAKE PERFORMANCE OF EXISTING BUILDINGS**

**15.8.1. Seismic Performance Targeted in Existing or to be Strengthened Buildings**

The earthquake ground motion levels to be taken as a basis in determining the earthquake performance of existing or to be strengthened buildings and the minimum performance targets for buildings at these earthquake ground motion levels are given in **Table 3.4** .

**15.8.2. Earthquake Performance of Existing or to be Reinforced Buildings**

The earthquake performance of existing buildings is related to the condition of the expected damages in the building under the effect of the earthquake applied and it is defined on the basis of four different damage situations. **The** earthquake performance level of the building is determined by applying the calculation methods defined in **15.5** and **15.6** and deciding on the employee performances according to **15.7** . The rules to be applied to determine the earthquake performance of buildings are given below. The rules given here are valid for reinforced concrete, pre-engineered reinforced concrete and steel buildings. The rules to be applied in masonry buildings are given in **15.8.8** .

**15.8.3. Limited Damage Performance Level in Existing Buildings**

As a result of the calculations made for each earthquake direction applied on any floor of reinforced concrete buildings, maximum 20% of the beams can pass into the *Distinct Damage Zone* , but all other bearing elements are in the *Limited Damage Zone* . Provided that brittle damaged elements, if any, are reinforced, such buildings are considered to have a *Limited Damage Performance Level* . These exceptions do not apply to steel and prefabricated reinforced concrete buildings.

**15.8.4. Controlled Damage Performance Level in Existing Buildings**

Provided that brittle damaged elements, if any, are reinforced, buildings that meet the following conditions are considered to be at the *Controlled Damage Performance Level* :

**(a)** As a result of the calculations made for each earthquake direction applied in any floor of reinforced concrete buildings, at most 35% of the beams and vertical elements (columns, walls and reinforced partitions, excluding secondary (not included in the horizontal load bearing system) beams) walls) as many as defined in paragraph **(b)** below may pass into the *Forward Damage Zone* . These exceptions do not apply to steel and prefabricated reinforced concrete buildings.

**(b) The** total contribution of the vertical elements in the *Advanced Damage Zone* to the shear force carried by the vertical elements in each floor should be less than 20%. The ratio of the total shear forces of the vertical elements in the *Advanced Damage Zone* on the top floor to the sum of the shear forces of all vertical elements at that floor may be at most 40%.

**(c)** All other bearing elements are in the *Restricted Damage Zone* or *Significant Damage Zone* . However, the ratio of the shear forces carried by the vertical elements of which the *Distinct Damage Limit is* exceeded in both of the lower and upper sections of any floor to the shear force carried by all vertical elements in that floor should not exceed 30% (In the calculation with the linear method, at both of the lower and upper nodes Columns with more than one **Equation (7.3)** are not included in this calculation).

**15.8.5. Migration Prevention Performance Level in Existing Buildings**

Provided that all the *fragile* damaged elements are in the *Immigration Area* , the buildings that *meet the* following conditions are considered to be at the *Prevention of Migration Performance Level* :

**(a)** As a result of the calculations made for each earthquake direction applied in any floor of reinforced concrete buildings, excluding secondary (not included in the horizontal load bearing system) beams, at most 20% of the beams can pass into the *Collapse Zone* . These exceptions do not apply to steel and prefabricated reinforced concrete buildings.

**(b)** All other bearing elements are in the *Restricted Damage Zone* , *Significant Damage Zone* or *Advanced Damage Zone* . However, the ratio of the shear forces carried by the vertical elements of which the *Distinctive Damage Limit is* exceeded in both of the lower and upper sections of any floor to the shear force carried by all vertical elements in that floor should not exceed 30% (In the calculation with the linear method, at both the lower and upper nodes than **Eq. (7.3)** "column is a provided not be included in this calculation).

**(c)** The use of the building in its current state is harmful in terms of life safety.

**15.8.6. Immigration Status**

*If the building* fails to achieve the Migration *Prevention Performance Level* , it is in *Immigration Status* . The use of the building is harmful in terms of life safety.

**Next Topic**