General Properties of Cross Sections#
After selection of the running mode, the properties dialog for the new cross section appears. The general properties which determine the subsequent behaviour during calculation and the design of the cross section can be set here. These settings apply for all elements in the cross section, however, some global settings can be overwritten in any individual dialog of the cross section, e.g. in order to define a different material than the reference material.
The commands and options depend on the selected running mode. For example, in the running mode thin-walled steel the options for defining reinforcement are not available.
The number of the cross section is set by calling the command and cannot be modified subsequently. If the number of the cross section should be changed later, the cross section can be copied to a new number using the Clone command (right click on the symbol of the cross section in the Sidebar).
The number of the cross section is used for the identification of the cross section in other SOFiSTiK modules. Thus, the numbers of the cross sections can not be assigned twice.
The definition of a name is optional. The name can be modified subsequently and is used to identify the cross section.
The selected material defines the default material for the individual elements of the cross section. For the use of different materials within a cross section (e.g. concrete and structural steel for a composite cross section) , then the material, which is selected here, is the reference material.
The defined material have to be used in at least one cross section element. Otherwise the calculation will end with an error message.
Reinforcement material / Link reinforcement material
In the running modes for solid sections and for composite thin-walled cross sections the material for the reinforcement is defined here. The link reinforcement material is only valid for solid sections.
The preferred type of the beam element can specify here for the cross section.
Direction of the positive y axis
This setting allows the user to switch between the positive or negative view of the cross section.
A detailed description can be found in chapters “CTRL - Control of Analysis” and “SECT - Freely defined Cross Sections” in the manual AQUA.
Suppression of the rotation of the principal axes
With this option it is possible to suppress the rotation of the principal axes (refer to manual of the program AQUA record SECT item FSYM).
Maximum length of polygon edges
If this option is activated, a maximum permitted edge length of the cross section is taken into account in the calculation. So it is possible to determine fillets with varying precision.
If this option is not activated, the default settings from AQUA are used (refer to manual of the program AQUA record CTRL item OPT HMIN).
Maximum stitch of circle arcs
If it is activated, it defines the maximum rise of the arc which is permitted for the approximation to circular arcs or fillets with polygonal geometry.
If this option is not activated, the default settings from AQUA will be used (refer to manual of the program AQUA record CTRL item OPT HTOL).
Consideration of minimum reinforcement
Controls whether minimum reinforcement should be set for the calculation of the cross section values.
A detailed description of the different options is available in the record CTRL item OPT RFCS in the manual AQUA.
Default shear cut
Defines whether shear cuts should be generated automatically for a solid concrete cross section.
This input corresponds with the option CTRL SCUT in the program AQUA (refer to manual of the program AQUA record CTRL item OPT SCUT).
Shear cuts which are generated with this option do not lie automatically at the most relevant part of the cross section. Only frequent cases are considered here. The user must ensure that the generated shear cuts are useful for the intended purpose. If necessary, the shear cuts have to be defined manually.
Standard stress points
Defines whether stress points should be generated automatically with the calculation of the cross section.
This input corresponds with the option CTRL SCUT in the AQUA input (refer to manual of the program AQUA record CTRL item OPT SCUT).
Stress points which are generated with this option do not lie automatically at the most relevant positions of the cross section. Only frequent cases are considered here. The user must ensure that the generated stress points are useful for the intended purpose. If necessary, the stress points have to be defined manually.
Calculation of Cross Section Properties
Here it is possible to define which method should be used for the calculation of the cross section properties.
A description of the options is available in record CTRL item OPT STYP in the manual AQUA .
An explanation about the methods is available in the manual of the program AQUA in chapter ‘Shear Stresses in Solid Sections’.
Following methods are possible:
Finite element method This method is the default. It is additionally possible to save the finite element mesh in a subdirectory and to set a factor for the mesh density. The plastic forces are determined approximately about scaling of the elastic shear flow. Otherwise it is also possible to determine the plastic shear capacity based on shear deformation areas.
Integral equation method
Cross Section Class 4 EN 1993-1-5
A definition of a uniform compressive stress allows to determine the effective section values according to EN 1993-1-5 for a steel cross section of the section class 4. For the most unfavourable case the yield strength of the steel material has to be defined. This possiblity is valid for solid or thin-walled composite or steel sections.
In this tab, the values of the cross section which are calculated automatically in AQUA can be overwritten manually.
This possibility should be used with caution. It is recommended to check the results carefully, because the overwriting of the actual values can have an impact on the cross section design.
In this tab, the characteristic plastic forces of a composite or steel cross section which are calculated automatically in AQUA can be overwritten manually.
This possiblity should be used with caution. It is recommended to check the results carefully, because the overwriting of the actual values can have an impact on the cross section design.
Further documentation can be found in the manual AQUA in the description for “SV – Additional Cross Section Properties”.
The reinforcement layers for the longitudinal reinforcement of the cross section can be defined here. The layers are used then for the input of the longitudinal reinforcement
in the commands
Opening in the tab Perimetric Reinforcement , Line Reinforcement and Single Reinforcement.
A detailed description for these layers can be found in the chapter “LAY - Reinforcement Layers” in the manual AQUA.
In the tab Stages, up to 9 construction stages can be defined for a cross section. The numbers of the construction stages can be between 1 and 9999. The name of the stages is optional.
The construction stages defined here can then be assigned to individual cross section parts in their respective element dialogs.
The definition of construction stages is not checked automatically for consistency! Inconsistencies in the definition of the construction stages can possibly lead to problems in the further calculations.
A detailed description can be found in the chapter “CS - Construction Stages” in the manual AQUA.
The variables which are defined here can be used only with a CABD (Computer Aided Bridge Design) license!
It is possible to define the variables here or at the axis with another unit. E.g. in the case of a cross section in mm, the variable can be input in cm or m.
The importance of the variable is described with further background information about parameterized cross sections in the manual of the program AQUA chapter “SECT - Freely defined Cross Sections” in the subchapter “Parametric Sections”.
Variables with a fixed value can be created with the button
With the button
Delete Variable the highlighted variable is deleted after a confirmation.
Variables can be imported from a definition of an axis using the button