DNV Offshore Freight Containers Design and Certification b. General All Permanently attached lifting points on all new equipment constructed after 1st March 2002 for MSI should be designed to recognize Principal National Standards or Classification Guidelines. The general safety factor given to concrete failure mechanisms is 2.5 against the characteristic (5% fractile) strength of the concrete. MSI LIFTING LUG / PAD EYES DESIGN GUIDELINES 1. However, concrete cone failure is the most well-known and is a function of the concrete strength at time of lift, the edge distance and the embedment depth of the anchor. There are a few different concrete failure mechanisms that can occur and for a detailed analysis you should refer to VDI BV-BS 6205 or CEN/TS 1992-4. Therefore, a 5T anchor will typically survive a load of 15T before it breaks. Geometric Guidelines: There are some geometric guidelines to be considered as recommended. The steel capacity is stamped on every anchor head as is determined by taking the characteristic (5% fractile) strength of the anchor and dividing it by 3. By:- Syed Jaffry Aco Milic DESIGN OF LIFTING LUG INPUT Thickness Diameter of hole Dimension a Dimension e Ultimate.
Therefore, Safe Working Load of anchor > applied service load.Īlso, care needs to be given to assess each load case including demoulding, storage, transportation and erection as the carnage and concrete strength could differ for each.įlat panels can be relatively straight forward, but volumetric constructions add another dimension that can result in additional issues to overcome.Įach anchor is allocated a load class, but this can give a misleading level of confidence as it is only the steel capacity and the concrete capacity can be much lower. This is done largely to ensure that the risk of overloading of the lifting anchors is kept to a minimum. Often it is more important to have relevant experience in precast design, coupled with some good reliable design tools rather than a degree in structural or civil engineering.Īs it is heavily related to the crane and rigging industries, lifting design is one of the few remaining structural designs that still operates predominantly on a working stress design model rather than limit state design. The digital PDFs are encrypted and require both the Acrobat plug-in and the FileOpen Acrobat plug-in.Precast Lifting DesignWhilst this is a structural design and deals essentially with a concrete anchorage, its dynamic nature means that a lot of the aspects of structural engineering taught at Universities are not relevant or are only part of the picture.
#Lift lug design series
Key changes tó this revision óf BTH-1 include: Addition of chapter of requirements for Lifting Magnet Design with additional commentary found in a corresponding new Nonmandatory Appendix Addition of design requirements for new Design Category for specialized application in industries that require lifting designs based on a specified larger Design factor Addition of new requirements for Member Properties Updated Table 3-2.2-1 Limiting Width-Thickness Ratios for Compression Elements BTH-1 and B30.20 are to be used in conjunction with equipment described in other volumes of the ASME B30 series of Safety Standards.Ĭareful application of these Safety Standards will help users to comply with applicable regulations within their jurisdictions, while achieving the operational and safety benefits to be gained from the many industry best-practices detailed in these volumes. The design critéria set forth aré minimum requirements thát may be incréased at the discrétion of the Iifting device manufacturer ór a qualified pérson.
As such, this Standard should be used in conjunction with B30.20, which addresses safety requirements.
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