VERSION HISTORY
LIRA-FEM
Soil
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In LIRA-FEM, pile foundation calculation has been implemented according to DBN V.2.1-10-2009. Settlement of piles is calculated, including consideration of mutual influence of piles within a pile group.
Additional parameters are implemented for calculation: ultimate pile resistance Pu, proportionality limit load Pe, partial safety factors along the side surface kf and under the pile tip kp. These parameters can be determined automatically or specified manually by the user.
Calculation of pile bearing capacity is implemented: for driven, bored, cast-in-place piles, and transmission line support piles.
The obtained stiffnesses (FE 57) are used in generating the design model and allow accounting for joint behavior of piles, pile cap, foundation, and the superstructure.
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In LIRA-FEM, soil stability check around piles has been implemented under the condition of limiting design pressure [σ,z] transmitted to soil by pile side surfaces (this check shows the applicability of linear dependencies in pile calculation).
The program automatically calculates the maximum allowable pressure for each pile in the pile group, and it is possible for load cases or DCL to obtain a mosaic plot comparing actual pressures to allowable: σ,z/[σ,z].
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Implemented calculation of piles in collapsible soils considering changes in pile foundation behavior during development of subsidence deformations.
Ensured more accurate consideration of the “foundation–pile cap–structure” system interaction, including transformation of negative skin friction forces of collapsible soil layers along the pile side surface into loads on the pile and refinement of force distribution in piles and pile cap.
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Implemented automatic calculation of conditional pile embedment depth in soil L1, used in pile strength calculations within the bar element design model.
- Improved speed of displaying contour plots and soil calculation (soil calculation acceleration reaches 1.6–8 times compared to previous implementation).
- Added setting Zero side resistance of piles for fill soils. Calculation responds to the soil type flag set in the Soil characteristics table.
- For calculation of parameter αε, a unified approach has been implemented with averaging of soil proportionality coefficient K according to a triangular law at user-defined depth Lk. This value is then used in calculations of conditional embedment depth, pile pressure check on soil side surface, and other related calculations.
- Calculation of hd has also been refined: soil characteristics φI, cI, γI are averaged specifically over depth hd, improving accuracy of determining the zone where soil side resistance should be excluded from work.
- Added polygonal selection mode for load contours.
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Implemented new mosaic plots for piles:
- mosaic plots of pile effective length Ly, Lz;
- mosaic plots of negative skin friction forces Pn of collapsible soil layers along pile side surface by pile length (in FE57) and their sum (in FE57 at pile heads);
- ultimate pile pressure on soil [σ,z];
- soil bearing capacity exhaustion coefficient σ,z/[σ,z].