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Influence of earthquake according to JTJ 004-89

Only horizontal seismic force is considered according to JTJ 004-89.

Seismic force on structure

Seismic force acting on structure is provided by (Art. 3.1.5):




seismic force acting at the center of gravity of the wall above the ith cross section [kN/m]



coefficient of horizontal seismic acceleration



weight of the structure above the ith cross section [kN/m]



comprehensive influence factor, usually it's 0.25



importance coefficient for seismic design



distribution coefficient of horizontal earthquake along the wall

Recommended value of distribution coefficient ψiw (Tbl. 3.1.5):

Wall Height [m]

Security level

Calculation diagram for ψiw

Highway, A class and B class motorway

C class and D class motorway

H ≤ 12

ψiw = 1

ψiw = 1

H > 12

ψiw = 1

ψiw isn't considered when H ≤ 12 m which means parameter a and b don't work when H ≤ 12 m. a is the top value of the distribution map and b is the bottom value of the distribution map.

Seismic earth pressure

When computing seismic earth pressure, Coulomb theory is used and unite weight of soil γ, internal friction angle of soil φ and angle of friction structure-soil δ is replaced by γ / cos θ, sdasdasd φ - θ, δ + θ, where θ is seismic angle (Art. 3.1.6).

Seismic angel θ is determined by different option of seismic fortification intensity.

Water influence

Water influence according to Chinese standard is a little different from the water influence according to Mononobe-Okabe or Arrango theory by reducing the water influence using comprehensive influence factor Cz.

Seismic bearing capacity of subsoil

Seismic bearing capacity of subsoil is provided by (Art. 2.2.1):




seismic bearing capacity of subsoil



adjusting coefficient for seismic bearing capacity



characteristic value of bearing capacity which has been modified by the geometry of foundation

The above formula is as same as Art. 4.2.3 in GB 50011-2010 (Code for seismic design of buildings). Suggested values of ξa by different standards can be found here.

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