Dynamic Stiffness Parameters for Turbine Foundation 1

[sharathkumar]

How do we calculate Dynamic Spring and Damping Constants for bedrock and soil, for the case given below.

Type of Structure : Steam Turbine Generator
Operation Speed : 3600 rpm
Foundation : Pedestal Type, 46'x106'x42'high
Existing Ground Elev. : 790.0'
Top of Rock Elev. : 786.0'
Footing bottom elev. : 778.0'
Shear wave velocity (soil): 211 m/sec
Shear wave velocity (rock): 1275 m/sec

VALUABLE GUIDANCE IS HIGHLY APPRECIATED. THANKS IN ADVANCE.

 

[jdonville]

sharathkumar,

Basically, it appears that your foundation will be on rock, so I don't see where the soil shear wave velocity even comes in to play.

Anyhow, you might want to post this in a structural or mechanical engineering forum to get a more focused and useful response.

Jeff


Jeffrey T. Donville, PE
TTL Associates, Inc.

http://www.ttlassoc.com

 

[zaqqaz]

There are several approaches:

1-use empirical equations and relations, along with CPT data.

2-Use in situ testing techniques, like SASW and MASW method to evaluate the damping of the soil. For the spring constant you can use the plate bearing method.

3-Collect samples and use Resonant column test to evaluate the G and or E and damping of the soil at different level. Using a numerical analysis with the measured values you can estimate the spring constants of the soil.