What is Nehrp class?
The NEHRP is a national agency of the United State of America who provide the recommended provision for seismic regulations for new buildings and other structure. The resulting map will help the city assess its earthquake shaking vulnerability and mitigation.
What is soil shear wave velocity?
Shear wave velocity is a measure of the mechanical property of soil and can be measured in field and laboratory. Shear wave velocity measurement is used along with other parameters from other tests such as standard penetration test blow count, cone penetration resistance, etc.
How do you calculate shear wave velocity of soil?
The velocity at which shear waves propagate through bulk matter is called the shear wave velocity. It depends on the shear modulus and density of the material. Mathematically, that’s: Vs = √(G / ρ) .
What is average shear wave velocity?
The average shear-wave velocity to a depth of 30 m (Vs,30) is a commonly used parameter in seismic guidelines such as the National Earthquake Hazards Reduction Program (NEHRP) (1997).
Is Sandstone prone to liquefaction?
Low liquefaction potential includes NEHRP Soil Class B (consisting of rock: sandstone, limestone, shale). Moderate liquefaction potential includes NEHRP Soil Class C (hard or stiff soil, or gravel) and part of NEHRP Soil Class D (stiff soil, stiff clay, and some gravel).
What is shear wave velocity used for?
The shear wave velocity of soil and rock is one of the key components in establishing the design response spectra, and therefore the seismic design forces, for a building, bridge, or other structure. The shear wave velocity can be measured from in-situ field tests, such as cross-hole or downhole testing.
What is shear wave test?
MASW is a geophysical method of mapping the stiffness properties of soil in an 2D profile. The method is based on measuring the lower frequency surface waves in the range 3-30 Hz (Park et al., 2007). Execution of the test is easy and quick which makes it very economical compared to other field methods.
How do you calculate shear modulus of soil?
To find bulk and shear modulus of soil you need to find deformation modulus and poisson’s ratio by plate load test ..then you can use these value to find bulk and shear modulus . Some software has inbuilt capability to calculate bulk and shear modulus from deformation modulus and poission’s ratio.
How do you calculate average wave velocity?
Wave speed is the distance a wave travels in a given amount of time, such as the number of meters it travels per second. Wave speed is related to wavelength and wave frequency by the equation: Speed = Wavelength x Frequency. This equation can be used to calculate wave speed when wavelength and frequency are known.
What is liquefaction potential of soil?
In this report, liquefaction potential refers to any of the entire spectrum of events resulting from the application of seismic shear stresses to saturated cohesionless soil deposits that could ultimately give rise to a loss of shearing resistance or to the development of excessive strains.
What type of soil is prone to liquefaction?
Poorly drained fine-grained soils such as sandy, silty, and gravelly soils are the most susceptible to liquefaction. Granular soils are made up of a mix of soil and pore spaces. When earthquake shock occurs in waterlogged soils, the water-filled pore spaces collapse, which decreases the overall volume of the soil.
What is the velocity of a typical SH wave in Kentucky?
Sites away from the active floodplains in western Kentucky and western Tennessee, the SH-wave velocities of the upper 30 m of soils typically ranged from mid-200 to mid-300 m/s.
What is the average SH-wave velocity in the Mississippi River floodplain?
Based on the average SH-wave velocities of the upper 30 m of the soils, sites in the Mississippi River floodplain portion of the study area are predominantly classified as Site Class D (180-360 m/s) in accordance with the 1997 NEHRP provisions.
What is the SH-wave velocity of a typical SH wave?
Several sites in western Kentucky had averaged SH-wave velocities greater than 360 m/s, thereby qualifying them as Site Class C (360-760 m/s) in accordance with the 1997 NEHRP provisions.