Vibration Problems and Seismic Effects - Areas of Significant Frost Penetration..

(1) Foundations supported on frozen ground may be affected by high stress-type dynamic loadings, such as shock loadings from high-yield explosions, by lower stress pulse-type loadings as from
earthquakes or impacts, or by relatively low-stress, relatively low-frequency, steady-state vibrations. In general, the same procedures used for nonfrozen soil conditions are applicable to frozen soils.  Design criteria are given in TM 5-809-10/AFM 88-3; TM 5- 856-4; TM  5-852-4/AFM  88-19.  These manuals also contain references to sources of data on the general behavior and properties of nonfrozen soils under dynamic load and discuss types of laboratory and field tests available.

However, design criteria, test techniques, and methods of analysis are not yet firmly established for engineering problems of dynamic loading of foundations.  Therefore, the Office, Chief of Engineers, ATTN: DAEN- ECE-T, WASH DC 20314, or HQUSAF/PREE, WASH DC 20332, should be notified upon initiation of design and should participate in establishing criteria and approach and in planning field and laboratory tests.

(2) All design approaches require knowledge of the response characteristics of the foundation materials,
frozen or nonfrozen, under the particular load involved.

As dynamic loadings occur in a range of stresses, frequencies, and types (shock, pulse, steadystate vibrations, etc.), and the response of the soil varies depending upon the load characteristics, the required data must be obtained from tests that produce the same responses as the actual load.  Different design criteria are used for the different types of dynamic loading, and different parameters are required.  Such properties as moduli, damping ability, and velocity of propagation vary significantly with such factors as dynamic stress, strain, frequency, temperature, and soil type and condition.  TM 5-852-4/AFM 88-19, discusses these properties for frozen ground.

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