Taiwan  [ Back to Seismic Design Code Index ]   [ Back to Country Index ]
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Holizontal Basic Shear



Z = seismic zone factor
K = framing coefficient
C = seismic force coefficient
I  = occupancy importance factor
W = total dead load

For warehouses or storage facilities, W is the total dead load and at least one-fourth of the design live load. For water towers or water tanks, W is the total dead load and the total weight of the contained water (e.g., tank completely filled).


Basic Seismic Coefficient The seismic force coefficient C for Taipei (the nation's capital and principal metropolitan area) is given by 


T = the fundamental period of vibration

For other regions of the country, C can be determined from



Seismic Zone

Table 1
Seismic Zone Factor (Z)

Seismic Zone

Zone Factor Z

W (weak earthquakes)
(moderate earthquakes)
(strong earthquakes)


Fig 1   Seismic map of  Taiwan



Importance Factor

Table 2
Occupancy importance Factor

I = 1.50

For essential structures that must remain operational at all times; e.g., fire and police stations, hospitals, power and water-supply plants, and structures containing natural gas and gasoline storage facilities.

I = 1.25

For public buildings such as schools, gymnasiums, museums, galleries, libraries, conference rooms, theaters, ballrooms, auditoriums, and any other similar structures that may house more than 300 people.

I = 1.00

For all other structures.



Structural Performance
Table 3
Framing Coefficient

K = 0.67

For ductile moment-resisting frames

K = 0.80

For ductile moment-resisting frames with shear walls or lateral bracing systems, K = 0.80 provided that one of the following conditions is met:

1.        Frames interact with shear walls or lateral braces structurally, and the total lateral force is resisted by each component proportionally to the component stillness.

2.        Shear walls or lateral braces function separately from the ductile frames, but resist the total lateral force.

3.        Ductile frames resist at least one-fourth of the total lateral force.

K = 1.33 For structural systems resisting the lateral force totally by shear walls,
K = 1.00 For structures other than those described above
K = 2.00 For nonstructural systems

I = 2.50


For water towers and water tanks that have cross-lateral bracing and are supported by four or more legs not attached to the structural system (i.e., the legs are attached to the ground)
 However, in this case, K times C must not be less than 0.23.