Influence of Buckling
The analysis is preceded by the determination of characteristics of an ideal cross-section, in which the effect of the cement mixture cross-section is transformed into steel. The slenderness of element is determined as:
where: | lcr | - | element buckling length |
i | - | radius of gyration of the ideal cross-section |
where: | E | - | modulus of elasticity of the ideal cross-section |
I | - | moment of inertia of the ideal cross-section | |
Ncr | - | standard critical normal force, calculated in dependence on the method set in the "Micropiles" tab |
Recounted slenderness λp is determined next:
where: | Rsd | - | design strength of steel (in calculation based on the factor of safety design strength is equal to the standard strength) |
where: | Rs | - | standard strength of steel, entered in the frame "Material" |
γss | - | reliability coefficient of steel, entered in the "Micropiles" tab (limit states) |
Buckling coefficient χ is determined according to slenderness λp with the help of the following formulas:
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