Calculation settings (PRE-Stress)

Last modified by Fredrik Lagerström on 2022/01/04 16:48


The Calculation Settings tab has a number of options that govern the calculation, some of which may require an explanation.


The shear calculation settings defines Cot θ (“cot theta”) with θ being the angle of the concrete compression strut and the beam axis. The value affects the amount of required shear reinforcement according to EN 1992-1-1 6.2.3 and satisfies the condition


in the general case. In the case of hollowcore elements for the Swedish annex, the condition is instead 1 < cot θ < 3.

The user may choose to either calculate with shear reinforcement according to EN 1992-1-1 6.2.3 or without shear reinforcement (where this is allowed) according to EN 1992-1-1 6.2.2. The latter option also enables the option to use enhanced shear strength near supports.

The option to consider bending reinforcement is defined in EN 1992-1-1 or Sudden release is defined in EN 1992-1-1, and the special rules for monolithic constructions in EN 1992-1-1

The option 'Check vert. stresses in anchor zone...' enables the Splitting, Spalling and Bursting calculation for prestressed elements. See 3.2.4 for details.

The punching check is carried out for all point loads positioned along the hollowcore, in ultimate limit state according to EN1168 For point loads positioned close to a free edge of floor bay the capacity is reduced by a factor 2 during certain circumstances: the load is acting by more than 50% on the outermost web and placed reinforcement is insufficient. Sufficient reinforcement consist of there being at least one strand in the outermost web and transverse reinforcement is considered (at least 1.2 m fully anchored strips designed for a tensile force equal to the point load). The reduction is applied based on whether or not the reduction option is checked here.

For the Danish annex, an option to set the consequences class is offered. Note that this setting only affects material properties and not the loads themselves. This is pursuant to EN1992-1-1 (Table 2.1N) and EN1990 (Table A1.2(B+C)).

For hollow core slabs, there is an option to consider EN 1168 for calculating shear capacity close to supports. This replaces the capacity calculation according to EN 1992-1-1, expression (6.4) with corresponding expression in EN 1168

When there is active topping, EN1168 Annex F.2.2 allows for an additional way to calculate a composite shear capacity value. This value will override any other web shear capacity calculated. Ticking the box 'Composite web shear capacity according to EN1168 Annex F2.2' will enable this override.

Adjustment factors can be defined for both moment capacity and shear capacity. Modify these factors to scale (up or down) capacities calculated according to current code. This option may result in calculations on the unsafe side. The intention with these factors is to consolidate theoretical calculations with evidence from practical tests.


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PRE-Stress Documentation