Building Base and Building Height Limitation According to 12.2.1
Tp, all = Natural vibration period calculated in the same direction in the structural system.
Tp,top= Natural vibration period calculated in the same direction without taking into account all basement masses including the ground floor in the structural system.
12.2.1 Structural System Selection
The structural system limitations and the limits on structural height, hn, are contained in Table 12.2-1.