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Offshore Ring Plate

Last updated June 9, 2014 by Steel Extensions tekla.extensions-steel@trimble.com

Software version: 
Not environment-specific

Offshore Ring Plate


Purpose and description
System Requirements
Installing Offshore Ring Plate
Using Offshore Ring Plate
Offshore Ring Plate settings
Customizing Offshore Ring Plate
Additional information
Limitations on Split Plates
Trouble Shooting

Purpose and description

This plugin will create offshore ring plates and cap plate connections which are needed at the connection of beam flanges and round pipe columns. The geometry of the ring plates is potentially quite complex and this tool will easily generate parts which are very cumbersome to create manually.

This tool focuses only on the creation of the ring plate. The connection between the web of the beams and the ring plate, or the web and the pipe are out of its scope. However, once the ring plate has been created, these details and connections are much easier to create using existing tools and custom components.

System requirements

Tekla Structures version 18.0
.NET Framework version: 4.0
Environments: Default

Installing Offshore Ring Plate

To install the extension:

1. Close Tekla Structures.
2. Install the application using the appropriate 32bit (x86) or 64bit installation package.

Using Offshore Ring Plate

To use the extension:

  1. Open the Component Catalog (Ctrl + F).
  2. Either use 'Search' or browse the 'Plugins' category to find the OffshoreRingPlate extension and click on its icon to start it.
  3. Select a single round pipe column as the main (primary) part.
  4. Select up to ten H beams or plate beams as secondary parts.
  5. The plugin will attempt to generate a shaped contour plate that connects the secondarys to the primary.

Setting Out

The plugin will use the first secondary beam as a datum from which to set the level of the Ring Plate. The plate's position relative to this may be modified using settings described later in this document.

Extension Properties

The Picture Tab:

Parameter Default Description

Parameter Default Description
Cut Yes Yes / No option to cut a hole in the ring plate around the pipe.
Gap 0 Gap between the pipe and the ring plate when a hole is cut.
Radius R 1.5*radius of the main pipe The radius of the basic ring plate.
Split plate No Yes / No option to split the ring plate in two.
Angle A 45 The angle of the split line, measured counterclockwise from the axis pointing along Beam 1.
eT 0 The amount of extra material to add along the split seam (see below for details).
The weld tab length.
The weld tab width.
The rounding of the corner at the weld tab.
Plate alignment Top Top / Bottom option to control the alignment of the ring plate with the beams / flanges.
Vertical offset 0 Option to offset the ring plate from the alignment line.
T 30 The thickness of the ring plate.
Prefix (options) The profile prefix for the ring plate.
Material (options) The material of the ring plate.
Name RINGPLATE The name for the ring plate.
Plate Prefix (options) The prefix for the ring plate part mark.
Plate Start No. (options) The start number for the ring plate part mark.
Assembly Prefix (options) The prefix for the ring plate assembly mark.
Assembly Start No. (options) The start number for the ring plate assembly mark.
Finish (blank) The finish for the ring plate.
Class 99 The class for the ring plate.

Note: where the default value is shown above as (options) the values used taken as those set in the Tools > Options > Options > Components menu.

The Beams Tab:

The Beams tab consists of a grid of up to ten rows in which to input and display properties related to each of the (up to ten) secondary beams/flanges. Use the'+' key to add rows to the bottom of the grid, highlight rows then click '-' to delete rows and use the '<' key to insert a row below the current row.
If properties are not entered for all beams, e.g. if there are four beams but only properties entered for beam 1 and 2, then the other beams will use the same properties as the last beam, beam 2. This means that for simple connections, the properties can be set for beam 1 and will be applied to all beams.


Parameter Default Description
L 2*pipe radius Length from the center of the main part to the edge of the flange along the axis of the beam.
E 0 The extension of the landing edge beyond the edge of the flange.
T 0 Taper length of the extension. If E is 0, T cannot be set or has no meaning if set. If T is 0, then the corner is square.
FL 0.5*pipe radius The rounding of the corner fillet between the left edge and the primary ring.
FR FL The rounding of the corner fillet between the right edge and the primary ring
Shape Fillet Option to select a Fillet, Straight or simple Rounded connection between the beam and the next beam.
R-Alt R An alternate radius or internal dimension for the connection between the current beam and the next beam.

The following example is intentionally complicated in order to illustrate how the variables and options are intended to work together. In the following example, the primary radius is set to 250, and no cut has been made in the plate (e.g. this is a cap plate).

Beam 1 to Beam 2 – An alternate radius of 300 has been given for the edge between these two beams.

Beam 2 to Beam 3 - The edge between beam 2 and 3 is specified to be straight. As no alternate radius is given, the straight edge is placed so that the minimum distance from the center to the edge is 250.

Because Beam 2 is slightly skewed, the straight edge will not be at exactly 45 degrees relative to the paper.

Beam 3 to Beam 4 – Nothing special here.

Beam 4 to Beam 1 – The fillets are both set to 150. The shape between is set to a simple round corner. Note however that because of the alignment and taper of the legs, even if the simple round corner were not specified, that is the only corner which would work in this case because the edges meet more than 250 away from the center.


5. Corner shape options and resulting geometry

Fillet corner: The shape of the ring plate at the connection of a flange is calculated / constructed as shown:

Round corner: In the diagram (below) it can be seen that it is not possible to create a Round corner between beams 1 and 2, so the logic will adopt a Fillet. However, between beams 2 and 3 a Round corner is possible, and the radius adopted would be that specified for beam 2 right.

Straight corner: If a Straight corner between two beams is selected, the construction is done similarly to a Fillet, but using a straight edge between the two outer radii. The straight edge is a tangent to the column circumference at radius R or Ralt if that is set.


Additional information

  • The plugin logic will attempt to generate the shape of corner selected by the user but in certain cases, such as for a single incoming beam, a Round or Straight corner geometry cannot not be generated so the plugin will automatically convert this setting to a Fillet style of corner.

  • Similarly, if the angle between two beams is too small for a Fillet style corner to be constructed it will revert to a Round corner.

  • If the Cut plate option has been set to Yes, and the weld tab dimensions eX and eY are both greater than 0, the plugin will attempt to create weld tabs in the specified location set by Angle A. Sometimes this may not be possible. For example it is not possible to fit a tab within the two outer radii of a Fillet corner, only in the single inner radius. Should tabs be specified but not generated, the plugin's cone symbol will be set to red. By changing the value of angle A and modifying the connection, it should be possible to try a variety of locations until a suitable position is found.

  • The Ring Plate is constructed as a polygon by creating an internal contour plate that is defined by the locations of the beams and which circumscribes the column in a series of facets. If a Split plate is specified, there will be two plates with start and end points that may be in any location as defined by the cut angle. Surrounding that inner plate are a series of additional plates, between each pair of beams. These may be shaped according to the user settings (Fillet, Round, or Straight). If a split plate is specified, there will be two plates broken along the cutting line. In some circumstances (such as if the cut goes through a chamfer) it will not be possible to make a valid pair of plates and either a single or no plates will be created. The outer plates are combined with the inner plates as 'Added Material'.

  • If the Cut option is set to Yes, then a part cut is used to remove the appropriate material from the inner contour plate.

Limitations on Split Plates

  • Splitting of plates can only be successful if both ends of the cut line fall in the zone between the outer fillets (as defined by FL and FR in the Beams tab).

  • Weld Tabs and any associated fillets (as defined by eR) must also fall inside the same points.

Trouble Shooting

  • Occasionally the input data may define a plate that it is not possible to model correctly. This is usually obvious as the plate becomes transparent.

  • If the reason for the problem is unclear it is suggested that the input data is simplified until the plate models correctly.

  • Suggestions for troubleshooting invalid plates:

    • Turn off any welding tabs if you suspect that their extents may be encroaching into corner chamfers.

    • Turn off the Split plate option completely or try changing the cut angle to ensure that it too doesn't encroach into any corner chamfers.

    • Try increasing the plate outer radius or change Ralt for the affected beam corner sector.

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