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In this section the software for static analysis of grillage-type foundations is deployed. It serves as a “black-box” program for optimization algorithms that should yield an optimal pile placement scheme under the grillage. The main purpose of the program is to return the reactive forces at all piles, and the maximum reactive force. Besides, it computes also all other parameters of deformed state of the grillage (see readme.txt).

Grillages are the most popular and effective scheme of foundations, especially in the case of weak grounds. The grillages consist of supporting piles and connecting beams. Exhaustive technical details on the grillages can be found, e.g., in L. C. Reese, W. M. Isenhower, S.-T. Wang, Analysis and Design of Shallow and Deep Foundations, Wiley, 2005.

The optimal grillage should meet twofold criteria: the number of piles should be minimal, and connecting beams should receive minimal possible torques. In fact, here we encounter two separate optimization problems: search for the minimal number of piles and search for the minimal volume of beams. Both problems can be integrated into one with a compromise objective function. We assume that the characteristics of piles and connecting beams are given and consider here the first optimization problem.

Initial data for the grillage optimization problem are the following:

  • The geometrical scheme of connecting beams
  • Cross-section data of all beams (area, moments of inertia)
  • Material data of all beams (material in one beam is treated as isotropic)
  • Positions of immovable piles (if any)
  • Maximum allowable reactive force at any pile
  • Minimum possible distance between adjacent piles
  • Vertical and two rotational stiffnesses (along the beam and normal to the beam) of pile
  • Loading data. Active forces can be applied in the form of concentrated loads and moments at any point on beam, or in the form of distributed trapezoidal loadings at any segment of beam.

The results of optimization are the number of required piles and their positions. To solve this problem it is necessary to find such a placement of the given number of piles that reactive forces do not exceed the carrying capacities of piles. If such a placement is not possible the number of piles should be increased.

Bylos atsisiuntimui

post date title description download
08.18.2009 Fortran library Library of Fortran routines in form of dll GRILLAGE.dll
08.18.2009 Fortran library Library of Fortran routines GRILLAGE.exp
08.18.2009 Fortran library Library of Fortran routines in form of lib GRILLAGE.lib
08.18.2009 Data file archive 12 initial data files, archived data_files.tar.gz
08.18.2009 Example Black-Box Grillage analysis programs in form of "black-box" routine. Example of main Fortran program using this "black-box". Black-Box.f90
08.18.2009 Example main program Grillage analysis programs in form of independent program. Example of main Fortran program. Example_main_Program.for
08.18.2009 Initial files 12 initial data files Initial_files.rar
08.18.2009 Readme Instructions readme.txt
08.18.2009 Archive, Fortran library for Linux Library of Fortran programs for Linux grillage.tgz

System requirements:

  • MS Windows operating system,
  • Compaq Visual Fortran 6 compiler.