Pakistan Table 1

Seismic coefficient Cv

Soil Profile Type1 Seismic Zone Factor, Z2
Z = 0.075 Z = 0.15 Z = 0.2 Z = 0.3 Z = 0.4
SA 0.06 0.12 0.16 0.24 0.32Nv
SB 0.08 0.15 0.20 0.30 0.40Nv
SC 0.13 0.25 0.32 0.45 0.56Nv
SD 0.18 0.32 0.40 0.54 0.64Nv
SE 0.26 0.50 0.64 0.84 0.96Nv
SF See Footnote4

1For soil profile types, see Table1-1.
2Seismic Zone factor Z shall be determined from Table7.
3For Near Source Factor Nv, see Table1-2.
4Site Specific geotechnical investigation and dynamic site response analysis shall be performed to determine seismic coefficients for Soil Profile Type SF



Pakistan Table1-1

Soil Profile Types

Soil Profile Type Soil Profile Name / Generic Description Average Properties for Top 30 M (100ft) of Soil Profile1
Shear Wave Velocity, vs m/sec (ft/sec) Standard Penetration Tests, N [or NCH for cohesionless soil layers] (blows/foot) Undrained Shear Strenght, su kPa psf
SA Hard Rock >1,500
(>4,900)
- -
SB Rock 750 to 1,500
(2,460 to 4,920)
SC Very Dense Soil and
Soft Rock
350 to 750
(1,150 to 2,460)
>50 >100
(>2,088)
SD Stiff Soil Prifile 175 to 350
(575 to 1,150)
15 to 50 50 to 100
(1,044 to 2,088)
SE1 Soft soil Profile <175
(<575)
<15 <50
(<1,044)
SF Soil requiring Site-specific Evaluation. See Footnote2.

1Soil Profile Type SE also includes any profile with more than 3 m (10 ft) of soft clay defined as a soil with a plasticity index, PI > 20,
wmc ≥ 40 percent and su > kPa (522 psf). The Plasticity Index, PI, and the moisture content, wmc, shall be determined in accordance with
the latest ASTM procedures.

2 Soils requiring site-specific evaluation:
  1.Soils vulnerable to potential failure or collapse under seismic loading such as
liquefiable soils, quick and highly sensitive clays, collapsible weakly cemented soils
2.Peats and/or highly organic clays [H > 3 m (10 ft.) of peat and/or highly organic clay
where H = thickness of soil]
3.Very high plasticity clays [H > 7.5 m (25 ft.) with PI > 75]
4.Very thick soft/medium stiff clays [H > 37 m (120 ft.)]
Exception: When the soil properties are not known in sufficient detail to determine the soil profile type, generally Type SD shall be used. Soil Profile Type SE need not be assumed for all situations unless the engineer determines that Soil Profile Type SE may be present at the site or in the event that Type SE is established by geotechnical data.


Pakistan Table1-2

Near Source Factor Nv1

Seismic Source Type4 Closest Distance to Known Seismic Source2,3
≤ 2 km 5 km 10 km &gl 15 km
A 2.0 1.6 1.2 1.0
B 1.6 1.2 1.0 1.0
C 1.0 1.0 1.0 1.0

1The Near Source Factor may be based on the linear interpolation of values for distances other than those shown in the table.
2The location and type of seismic source to be used for design shall be established based on approved geotechnical data.
3The closest distance to seismic sourve shall be taken as the minimum distance between the site and the areas described by the vertical projection of the source on the surface (i.e., surface projection of fault plane). The surface projection need not include portions of the source at depths of 10 km or greater. The largest value of the Near-Source Factor considering all sources shall be used for design.
4For Seismic Source Type, See
Table1-3.