Tall tower with lower car parks

[andrew17]

design a 15 story tower with very large area of low rised shopping area (5 story).

if running in a modal response method, do i need to worry about lower area with different period (much less)?

right now the Tx=2s is governed by the tall tower i believe.

for example, if i remove the tower above parking area, Tx will become 0.4s, so it has higher design acceleration but less mass participating lateral movement.

is it worth to check the structure without the tall tower? Or modal response method will distribute a suitable acceleration to different floor height/joints, so the low rised parking area will get an appropriate design force automatically?

please share your understanding if you have designed multi-tower structure with common base floors.

 

[chekre]

Your model should include all the elements of the substructure as well as the superstructurr.
Morover, u have to consider the backstay effect in the podiums since there will a sudden change in stiffness between the basement level and the first floor of your tower.