Lifting Lug - Lug Information

Owned by Former user (Deleted)
Last updated: Jul 31, 2019 by Mike Clark
5 min read

Last Updated: 2019.7

Temperature: The maximum mean metal design temperature for the lug.

Lug Width/Lug Length: The horizontal dimension (in vessel operating position) of the lug at its base. Lug Length is used for horizontal vessels and Lug Width is for vertical vessels.

Shackle Hole Diameter: Diameter of the hole where the lifting equipment will be attached to the lug.

Shackle Hole Centerline Height: Distance from the base of the lug to the center of the shackle hole on type 1, 2, and 3 lifting lugs. For Type 4 lifting lugs, this is the axial distance from the base of the lug to the center of the shackle hole (see the figure on the General Information tab in the software for more information).

Lug Weld Leg: The fillet weld leg between the lug and the repad or the lug and the host.

Weld Joint Efficiency: Multiplier on the allowable stress of the materials attached by the fillet weld. A lower value is considered more conservative and this value cannot exceed 1.0.

Weld Len. Omitted over head Weld: The length along opposite edges of the lifting lug where the weld stops and then restarts to avoid welding over the head to shell seam. This field is only available when 3 or 4 is selected as the "Support Type."

Lug Thickness: The thickness of the lug.

Lug Radius:  The radial distance from the center of the shackle hole to the outside edge of the lifting lug.

Lug Foot Height: Available when type 2 or 4 lifting lug is selected as the "Support Type". On type 2 lifting lugs, this is the dimension on the lifting lug from the base to where the lug cross-section changes. On type 4 lifting lugs, this is the dimension on the lifting lug from the base to where the lug is bent. See the figure on the General Information tab of the software for more information.

Lug Angle: The angle at which the lug cross-section reduces, starting at the top of the lug foot height. This field is only available for Type 2 lugs.

Lug Weld Height: The measurement of the weld from its lowest point on the side of the lug to the highest point. The total length of the welds on the sides of the lug is 2x the weld height minus 2x the omitted length.

Add Weld Notch: Select this box to add a weld notch to the bottom of the lug. This will add a length of weld equal to pi times the radius of the weld notch.

in. Radius of Weld Notch: The weld notch is assumed to be a half-circle of this radius and located in the bottom-center of the lug.

Use Repad: Select this box to add a reinforcing pad between the lug and the host. This option is only available for lifting lugs on horizontal vessels (Types 1 and 2).

Lug Material

Material: A brief description of the component material. When the material selection dialog is used, the default description is based on settings on the Materials-Misc. tab under Tools > Defaults. For example, if the settings are for Spec and Type/Grade and the material is SA-516 Grade 70, this field will show SA-516 Gr. 70. If the settings are instead just for Spec, the field will show SA-516. The field may be edited by the user to say anything without breaking the relationship to the material database; while this flexibility can be very helpful, the user must take care to enter correct information.

Condition: A brief description of the component material. Similar to the "Material" field, the description will default a certain way based on settings on the Materials-Misc. tab under Tools > Defaults when the material selection is used. This field may be edited by the user without breaking the relationship to the material database. As with the “Material” field, the user must take care to enter correct information.

Density: The material density based on table PRD from Section II, Part D. For those materials that did not have a clear match in this table, every effort was made to assign conservative values. Manually editing this field will sever the connection to the material in the database as indicated by the "Unlisted Material" caption.

Modulus of Elasticity: The material modulus of elasticity based on the TM tables from Section II, Part D. The value shown here is based on the applicable TM table and the design temperature listed for lug. In cases where the lug temperature listed exceeds the highest temperature entry for this material’s TM table, the value will be zero. There are several materials that do not have clear matches in these tables. When a clear match cannot be found by the software’s assignment criteria, the software will instead retrieve the modulus of elasticity from the external pressure chart assigned to the material. If this attempt also fails, then the value will be zero. This is more common with non-ferrous materials. Manually editing this field will sever the connection to the material in the database as indicated by the “Unlisted Material” caption.

Stress (Hot): The material allowable stress at the lug temperature. When a 3.5:1 safety factor is specified in the vessel screen, this value comes from Section II, Part D (Table 1A for Ferrous Materials, Table 1B for Non-Ferrous Materials, and Table 3 for Bolting). If a 4:1 safety factor is specified, this value is calculated based on the ultimate strength from Table U in Section II, Part D; furthermore, the value is limited to the values listed in the allowable stress tables for yield and creep governed cases. In cases where the lug temperature exceeds the highest temperature entry for this material’s stress line, the value will be zero. Manually editing this field will inform the software that the user is defining the material differently than what is stored in the database and the connection to the material in the database will be severed. This is indicated by the “Unlisted Material” caption.

Stress (Cold): The material allowable stress at 70 °F (20 °C). When a 3.5:1 safety factor is specified in the vessel screen, this value comes from Section II, Part D (Table 1A for Ferrous Materials, Table 1B for Non-Ferrous Materials, and Table 3 for Bolting). If a 4:1 safety factor is specified, this value is calculated based on the ultimate strength from Table U in Section II, Part D; furthermore, the value is limited to the values listed in the allowable stress tables for yield and creep governed cases. Manually editing this field will sever the connection to the material in the database as indicated by the “Unlisted Material” caption.

Yield Strength: The material yield strength at the lug temperature. This value comes from Section II, Part D, Table Y-1. In cases where the lug temperature exceeds the highest temperature entry for this material’s yield line, the value will be zero. There are several materials that do not have clear matches in these tables. When a clear match cannot be found by the software’s assignment criteria, the software will calculate the yield strength using the external pressure chart and the method described in UG-28(c)(2) Step 3. This is more common with non-ferrous materials. If no match is found and the software cannot perform the described calculation, this value will be zero. Manually editing this field will inform the software that the user is defining the material differently than what is stored in the database and the connection to the material in the database will be severed. This is indicated by the “Unlisted Material” caption.