I found the mistakes. I released the freedoms of members for the main frames, so the whole building was acting as a mechanism. That's why I got huge fundemental periods.
I was also setting the loads to all horrizontal beams at both directions at a time. To correct that mistake, I selected and loaded the beams which the earthquake was alligned to. For example, x direction earthquake, x direction beams (as a part of the primary frames of course).
I hope this helps for others when doing earthquake loading.
I was also setting the loads to all horrizontal beams at both directions at a time. To correct that mistake, I selected and loaded the beams which the earthquake was alligned to. For example, x direction earthquake, x direction beams (as a part of the primary frames of course).
I hope this helps for others when doing earthquake loading.