Lift Lug Design and Application

Abstract For lift lug design there is a good attachment design reference in the Welding Research Council 537 specification (WRC537) that is useful for designing lift lugs on cylindrical components with respect to local stresses. An adequately designed lift lug is only as good as its practical application. All lift lugs will vary in capacity based on the lifting orientation (weak axis versus strong axis), lug geometry and dynamic effect caused by the loading. Based on a review of industry standards, an approach is presented on how to design a lift lug for base metal and weld metal. Several design references including the Design of Below-the-Hook Lifting Devices (ASME BTH-1) specification, Pressure Vessel Handbook by Megyessy with respect to weld lines, Pressure Vessel Design Handbook by Bednar, WRC537 for local stress analysis of cylindrical and head attachments and the American Petroleum Institute (API) 2A-WSD Working Stress Design code for designing off-share platforms are reviewed. A Finite Element Analysis (FEA) approach will be discussed. This paper will provide a proposal for applying accepted theory towards the design of lift lugs in addition to the important aspects of the actual lifting of a component including the effect of lifting angle and rotation on lug capacity.