Uniform load distribution
The ring girder averages out the concentrated reactions from discrete support points, presenting the vessel shell with a nearly uniform radial load.
Horizontal vessel variant
For horizontal ring supports, the elevation field is relabelled Distance from Head Weld and the bolt circle field becomes Anchor span (transverse) to reflect the different mounting geometry.
Parameters
Position
Vertical position of the ring support on the vessel.
- For vertical vessels: elevation above the vessel datum (bottom tangent line).
- For horizontal vessels: distance from the nearest head tangent weld line to the ring centreline. The field label changes to Distance from Head Weld automatically.
Height of the ring support assembly measured from the supporting structure to the vessel shell contact point. Only shown when the vessel type is Horizontal.
Ring Profile
Cross-section type of the ring girder. Options: Type A or Type B.
- Type A
- Type B
Type A is a T-section ring with a single flange. The web plate is oriented radially and the flange is attached at the outer edge. This profile is used where the ring is primarily loaded in bending about its radial axis and space constraints limit the section depth.
Ring Dimensions
Outside diameter of the ring girder. For a ring welded to the vessel shell, this value is typically the vessel shell OD plus twice the web height.
Inside diameter of the ring girder. For a ring welded to the vessel shell OD,
ringID equals the vessel shell OD. ringOD minus ringID gives twice the web height.Description or designation of any access or lightening holes in the ring web (e.g.,
Round 50mm or Oval 100x50). Holes reduce section area and must be accounted for in stress calculations.Web Geometry
Radial height of the ring web plate, measured from the vessel shell OD (or ring ID) to the outer flange face. Increasing web height increases the section modulus and reduces bending stress.
Thickness of the ring web plate. The web is checked for shear stress and local buckling.
Flange Geometry
Width of the ring flange plate. For Type A, this is the outer flange. For Type B, this dimension applies to both the inner and outer flanges. The flange provides the primary bending resistance.
Thickness of the ring flange plate. Combined with
ringFlangeWidth, defines the flange cross-sectional area and moment of inertia contribution.Gusset Plates
Whether gusset plates are welded to the ring to increase torsional stiffness and improve load transfer at support points. Options: Yes or No.
Number of gusset plates equally spaced around the ring circumference. Gussets are typically located at each support column or beam intersection.
Thickness of each gusset plate. Gussets are checked for shear and bearing at their connection to the ring web and flange.
Width (radial extent) of each gusset plate. A wider gusset engages more of the web area and provides a larger weld length to the vessel shell or inner flange.
Anchor Geometry
Pitch circle diameter on which anchor bolts are located.
- For vertical vessels: labelled Bolt circle. Anchor bolts pass through the ring flange into the supporting structure below.
- For horizontal vessels: labelled Anchor span (transverse). Represents the distance between anchor bolt centrelines measured perpendicular to the vessel axis.