Geotechnical Research Centre

DYNA6.1 - Frequently Asked Questions Page 2

Does DYNA6.1 handle pile supported machinery foundations?

Yes, it does handle pile supported machinery foundations.

We have a power plant project and now designing a foundation for the gas turbine and generators. Can the software generate more than one natural frequency of the system (consists of machine + foundation + soil)?

DYNA6.1 will show at least six modes (i.e. six natural frequencies) associated with the rigid body movements. This means you will have a natural frequency along the vertical and two horizontal directions as well as torsional and two rocking directions. After you run DYNA6.1, you can plot the responses vs. frequency at the C.G. of the machine-foundation system. These responses will display peaks. The location of the peak identifies the natural frequency.

Our company has a pump foundation design that needs to be dynamic analysis.

DYNA6.1 can solve the problem you cited.  It is very widely used in the industry for similar projects.

Does DYNA6.1 software address superstructure such as for a steam turbine?

Yes, but assumes rigid body movement, which is justified in many cases depending on the dimensions of the tabletop. If you want to consider flexibility of tabletop, the program provides frequency dependent stiffness and damping constants that can be used in FE to obtain the response to the dynamic loads. In this case, DYNA6.1 can be used in the preliminary design until a foundation configuration is selected, then FE can be used to verify its suitability.

The geotechnical report includes a Cross-Hole and a Down-Hole for the dynamic properties of the soil.  The equipment (a Gas Turbine) is meant to be founded with steel pipe piles.  Is DYNA6.1 able to provide the dynamic spring constants for modeling the interaction between the steel pipe piles and the soil?

Yes, DYNA6.1 provides frequency-dependent stiffness and damping constants and accounts for the interaction between the piles (steel or concrete) and soil considering the group effect. It also accounts for the interaction of the pile cap with the adjacent soil if there is an embedded pile cap.

I would like to ask about the estimation of the liquefaction potential of soils under the effect of earthquake and other types of dynamic loading such as impact and harmonic loading.  In addition, the ability of the program to modle the coupled analysis of saturated soil in static and dynamic loading.  Does the output of your software include the coupled results of stress and pore water pressure?

DYNA6.1 performs dynamic analysis to evaluate the response of shallow and deep foundations subjected to dynamic loads (harmonic, transient, impact and random).  It does not perform static analysis or effective stress analysis and no liquefaction calculations.  It is purely linear elastic analysis.

Is the software able to analyze the effects of several machines on isolated but adjacent foundations or several adjacent machines on the same foundation?

It can calculate the response for several machines on the same foundation, but not isolated foundations.

I am studying the dynamic effect of a compressor on a pile supported foundation.  I am particularly interested in the resonance frequencies of the slab and the acting frequencies of the machine.

Indeed, DYNA6.1 is well-suited for your application and is used worldwide for this purpose.

We are interested to purchase DYNA6.1 to design and analyze dynamic equipment foundations such as STG, CTG, and fan foundations.

DYNA6.1 can be used for the design of STG, CTG and fan, motor, pump, foundations.

What are the typical input parameters one would require to use the DYNA6.1 program (i.e. CPTu charts, N60 values, densities, strengths, etc.)?

Soil parameters required are:  1.  soil shear wave velocity, Vs, which can be obtained from CPT test or through correlation with SPT N values or can be measured using seismic methods (eg. MASW); 2.  unit weight of soil; 3. Poisson's ratio; and 4. damping ratio (usually estimated between 0.02 and 0.03).  In addition, you input geometry of foundation (shallow or deep).

Note:  The program has a help menu that provides a detailed description of all input.