Dynamic Subgrade Modulus
Dynamic Subgrade Modulus
(OP)
I'm working on a project in which the structural engineer is requesting values for "dynamic subgrade modulus" for input to his computer model. This will apparently be used for modeling the dynamic response of the soil foundation. I'm not familiar with this parameter, and this is the first time this has been requested. Any help with references and/or experience with this is apppreciated!





RE: Dynamic Subgrade Modulus
RE: Dynamic Subgrade Modulus
See "Design of Structures and Foundations for Vibrating Machines," by Suresh Arya, Michael O'neill and George Pincus.
RE: Dynamic Subgrade Modulus
Get a local CPTU contractor to perform a SCPTU test.
Using a shear wave source at the ground surface, a single SCPTU test will give you all the necessary data for determining the modulus of supgrade reaction.
We have always avoid doing cross hole seismic testing due to the costs. On other projects I have compared downhole and crosshole seismic data. Both types of testing usually produce the same results.
If you have ground that is not "cone-able" then you could install casing and conduct Vs testing in a cased hole. Maybe a local geophysics company could do testing from the ground surface?
Coneboy
RE: Dynamic Subgrade Modulus
by the way, is the shear modulus often referred to as the dynamic subgrade modulus? i have thought these were two seperate "things". maybe i've misunderstood/confused something.
RE: Dynamic Subgrade Modulus
RWF7437: The reference is directed toward flexible pavement design and evaluation. The paper refers to "dynamic stiffness modulus (DSM)", which represents the average dynamic modulus of elasticity of subgrade materials.
I believe that this value is the same as the subgrade resilient modulus, Mr, which is also applicable to flexible pavements.
sdz: I do not believe that it is the dynamic shear modulus (G) that the engineer has asked for as I've given them a value for that.
coneboy: I've already provided a modulus of subgrade reaction for the design - their request is apparently about a "dynamic subgrade modulus".
msucog: Your question is mine, although I've only seen the dynamic shear modulus refered to as the dynamic shear modulus!
Still looking to clarify ......
RE: Dynamic Subgrade Modulus
RE: Dynamic Subgrade Modulus
RE: Dynamic Subgrade Modulus