RM Bridge Modeler Help

Cross section: Elements

RM requires a FE-mesh for the calculation of the cross section properties. The elements defined here will become finite elements. These elements are distinguished between steel and concrete elements, for RM this definition is not relevant. Always 9-nodes-Lagrange-elements are used in RM.

Note: RM needs cross sections having a consistent topology in the sense of a planeFE-system. Element borders and nodes must fit together to create a consistent element mesh.
SettingDescription
Merge Coincidient Slave Nodes How it works:
  • Select the beam parts interval where the program will search for any two or more slave parts at same position;
  • Based on the selected parts, the program will search through all shell elements assigned to them;
  • When two or more salve parts at same position is found, program will highlight corresponding shell elements;
  • When ok is pressed, the program will merge these slave parts into one and apply all needed corrections.

Input of elements

SettingDescription
Linear elements

Linear elements are created by clicking the corresponding symbol in the symbol row at the top of the window. Then, 4 intersection points have to be selected interactively. If the 4th point is identical to the 1st one,  a triangular element is defined. 4 points define a quadrangle.

The points have to be defined in a clockwise or anti-clockwise sequence. The new element is assigned to the currently active part (symbol row).

Parabolic elements

Parabolic elements allow an element definition with curved edges. The input requires the selection of 8 intersection points for a quadrangular element or 7 intersection points for a triangular element, where the 7th point must be the the same as the 1st one. The points have to be defined in a clockwise or anti-clockwise sequence. The new element is assigned to the currently active part (symbol row).

Stiffeners

Using the Stiffener tool, several types of stiffeners can be defined. The element division is made automatically by the program.

Note: Presently, only the input of U-stiffeners are available!

Work on elements

SettingDescription
Rounding

Edges of a defined concrete element can be rounded by specifying the radius. The rounding radius has to be entered positive or negative to produce a convex or concave rounding, respectively.

Shear element (shear lag)

The shear lag property is entered by defining elements as shear elements. These Shear elements are situated outside the shear lag. The element property "shear" (symbol "S") can be switched on or off by clicking the elements. Three different types are available:

Note: By clicking on the element the shear type can be changed.
Part assignment

To assign the beam elements via FE-cross sections to beams later in RM all elements have got a number of a cross section parts. The part number is automatically given. Elements belonging to the same part will form one single cross section in RM. When the symbol "Part assignment" has been clicked, each selected element will be assigned to the active part (see symbol row at top of window).

Copy elements

Elements can be copied by 4 different types. The copied elements keep the relation to their source elements. Only elements themselves will be copied, not the construction lines defining the source elements and not the objects ( reference points, stiffeners ) dependent on the source elements. The edge rounding of the source elements will be copied.

SettingDescription
"Copy to part"

Elements will be copied to the active part. A translation defined by the position of the destination part related to the position of the source part.

"Translation"

The translation of the elements is given by one chosen construction line ( direction ) and the active variable or the active value in the variable field.

"Rotation"

The Rotation of the elements is given by the chosen rotation point ( intersection of 2 construction lines ) and the active variable or the active value in the variable field.

"Mirroring"

The mirroring of the elements is given by one chosen construction line ( mirror axis ).