11.7.2.1 Members

Members

Continuous Beam

RFEM creates a continuous beam with supports, irregular spans, and a uniform cross-section. Optionally, load cases and result combinations are created as well.

2D Frame

Before you enter geometrical data and cross-section properties, select the Frame Type. The columns of the planar frame receive equal support conditions.

Tapered 2D Frame

The planar frame must be defined by its Geometry and Cross-Sections. Tapers, crane runway brackets, and eccentric joints are possible. Loads can be generated as well. The [Details] buttons provide access to the generator parameters. The frame position is important for load determination.

2D Truss

In the list, specify the Type of truss and the arrangement of the Diagonals. Then you can define the Parameters, Cross-Sections, and Member Types.

Grid

This generator creates models that have a uniform grid (for example, girder grillage). They do not need to be constructed with right angles as shown in the dialog graphic; any spatial quadrangle models are possible across the four corner points. To create a “real” beam grid, the model type should be set to 2D - in XY in the model base data (see Chapter 12.2).

• Online Manual RFEM 5 | 12 File Management | 12.2 Creating New Model

You can also use the [Details] button to generate irregular grids.

Column

In the Type dialog section, define if a center or corner column is generated. If you want to generate Loads, you have to specify their Effective Widths and Correction Factors.
For generating a gable column, the span a is required for the influence range in the longitudinal direction of the hall. The factors f₁ and f₂ are used to scale the geometric widths b₁ and b₂ for the static model or to fulfill specific code requirements (e.g. load increment factors for individual design checks).

Roof Generators

The Roof menu item provides three roof generators, which you can use to generate planar roof systems including loads (see following figures).

The [Settings] buttons in the roof dialog boxes help you to determine wind and snow loads (see Figure 11.155).

Roof → Collar roof

Roof → Rafter roof

Roof → Purlin roof

Fish Beam

To generate fish-bellied girders, which are mainly used in timber construction, the rectangular and ITS cross-section types (symmetric I-beams) are available for selection in the Cross-section type list.

3D Frame

Use this generator to create regular frame models. The columns of the frame receive equal support conditions.

3D Hall

This extensive generator creates a complete hall, including loads. Four dialog tabs are provided: Geometry/Support manages the system geometry, while Division/Arrays regulates irregular grid spacing and the arrangement of arrays. In the remaining two tabs, the Cross-Sections and Loads are defined.

3D Truss

You can use this generator to create a spatial load-bearing structure according to the Bernauer system.

3D Cell

This generator creates a spatial cell with several fields. Use the button shown on the left to open another dialog box where you can define openings as well as the grid arrangement for irregular field spacings.

Straight Stairway

In the list, select the Type of stairway, which determines the remaining parameters.

Spiral Staircase

Line

This function allows you to generate straight lines based on new or existing nodes. It is also possible to create only nodes that lie on an imaginary straight line.

Arch

First, the type of arc must be specified: circle, parabola, hyperbola, or catenary. Points A and B represent the two edge nodes of the arc, while point C controls its arrangement. The sag is specified using the stroke. The parameter L specifies the length of a catenary. This interacts with the heights h₁, h₂, and h₃.
The Parameter describes the constant a in the following equation of the catenary curve:

• where v_x or v_y: displacements in x or y

The larger the number of members is, the more precisely the arc is modeled as a polygonal chain.

Circle

The circle arc or full circle is defined by the Radius and Angles. The object is created around a center point that can be selected anywhere in one of the global planes.

Sphere

The larger the number of Planes and Meridians is, the rounder the shape of the sphere will be. The approximation to the spherical shape is achieved by polygon chains, with each segment corresponding to a member.

Bracings in Cells

Cells are defined by four corner nodes, enclosed by members on all sides and placed in a plane.
In the generator dialog box, specify the Members of Bracing and the Cells for Bracing or use the buttons to select them in the work window by clicking the cell crosses.
Virtual lines allow you to close cells so that bracings can also be created between wall supports, for example.