11.7.2.1 Members

Members

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

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

The planar frame must be defined by its Geometry and Cross-Sections. You can create tapers, craneway consoles, and eccentric connections. Loads can be generated as well. The buttons provide access to the generator parameters. The Frame location is important for the load determination.

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.

Use this generator to create models that have a uniform grid (e.g. gratings). They do not need to be designed with right angles as in the dialog graphic above. Any kind of spatial quadrangle model with four corner points is possible. To generate a "real" girder grillage, it is recommended to set the Type of Model to 2D - in XY in the model's general data (see Chapter 12.2).

To generate irregular grids, use the button.

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 designs).

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).

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.

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

This extensive generator creates a complete hall, including loads. Four dialog tabs are provided: Geometry/Supports manages the system geometry; Partitioning/Bracing controls irregular grid spacings and the arrangement of bracings. In the remaining two tabs, the Cross-Sections and Loads are defined.

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

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.

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

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

First, define the Type of Arc: circle, parabola, hyperbola, or catenary. Points A and B represent the two edge nodes of the arc, point C determines its arrangement. The Arch Rise defines the sag. The length of a catenary is defined by the parameter L. The heights h₁, h₂, and h₃ are interactive values.

The Parameter describes the constant a in the following equation of the catenary curve:

$y\left(x\right)=a\cosh \left(\frac{x-v_x}{a}\right)+v_{y }$

• 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.

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.

The larger the number of Planes and Meridians is, the rounder the shape of the sphere will be. Polygonal chains approximate the spherical form, with each member representing a segment.

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 button 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.