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A1- Torsion Irregularity Control

  • Torsional Irregularity Coefficient ηbi , which expresses the ratio of the maximum relative displacement of any storey to the average relative displacement at the same direction at that storey for any of two earthquake directions perpendicular to each other, is the case where ηbi is greater than 1.2.

  • According to Table 3.6 of TBDY 2018, the calculation of the relative storey drifts is made according to the Equivalent Lateral Force Procedure, taking into consideration the effects of ± 5% additional eccentricity.

  • Loadings made according to the equivalent lateral force procedure are separate and used only in the irregularity checks. These loads can be controlled from the structure tree in the program interface.

  • As per TBDY 2018, A1 irregularity is important in the selection of the linear analysis method to be applied for the building. However , as stated in the section Determining the Linear Calculation Method, Modal response spectrum analysis we use in this building can be used in all buildings in accordance with the earthquake regulations .

  • Irregularity checks are given in detail in the earthquake regulation report. As seen in the table below, there is no A1 type irregularity in the building.

  • If you want to check this report, the calculation is made on the displacement of the elements given in the report by using equivalent earthquake load loads in the perspective screen - analysis display - deformations sub-tab in the program interface.

  • For the X direction +5%, the values ​​of FX + must be checked. If we want to examine the 11th floor ∆i,max value, the values ​​read at the top joint point of the P1148 shearwall and the node connected to the 10th floor are shown in the visuals above.

i,max =66-59.7=6.3 mm

Note: It is aimed to see order accuracy in reading joint displacements through shell elements. Due to the size of the project, it is difficult to read as precisely as the values ​​printed in the reports. For this reason, the calculations given in the reports are more precise, the value found in manual calculation is approximation enough, but may not be exactly the same. This account is about 0.3%.

  • i,max and ∆i,min values ​​can be read from the program interface and all of them can be checked with excel.

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