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Vertical Seismic Response Spectrum Analysis (

  • The vertical earthquake effect is calculated automatically for the specified elements using the vertical elastic spectrum specified in 2.3.5 .

  • Elements to be used in the vertical elastic design spectrum are under user control.


D = Strength Excess Coefficient
R = Structural System Behavior Coefficient

It has been determined that the vertical earthquake effect, which was first used with TBDY 2018 , has an effect on the building behavior as a certain proportion of the horizontal earthquake effect, as a result of the experiments and monitoring the movements of the buildings under earthquakes. According to the regulation, it is calculated in 2 different ways. It is calculated by using the spectrum only for elements with certain properties, and as a certain ratio of the constant load for all other elements. Elements with specific propertiesVertical Earthquake Effects is described in theVertical Earthquake Effects section.

TBDY 2018 The element described in (a) - (d) should be selected, and the option Use spectrum for vertical earthquake effects should be activated in the 'TBDY 2018' tab in its properties. If the analysis is made after the selection is activated, the modal-vertical status in the modal analysis title of the structure tree can be examined, and the information is also included in the subtitle of loading states and loading combinations in the optional report.

Vertical spectrum is used only for selected elements. The acquisition of the vertical elastic design spectrum is explained in detail in the section Vertical Design Response Spectrum. According to the regulations, R = 1 and D = 1 are used in its account.

In cases where the vertical earthquake effect is calculated with the spectrum, the mode representing the vertical movement on the relevant element should be calculated. Even if the number of modes is sufficient for horizontal earthquake effect, if the relevant mode is not available, the targeted mode number should be increased and the relevant mode should be included in the calculation. Otherwise, internal forces and displacements for vertical earthquakes affecting the element cannot be calculated correctly.

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