spreader beam design for 5tons

[kerstinne25]

I am tasked to design and show the calculations for the spreader beam which is to lift maximum 5ton steel bar materials. Will be using an 2meters long I-beam, with shackles at both ends to which a wire rope shall be attached to be connected to crane hoist. My problem, i really don't know where to start my design and calculation. please help me. They need to see the actual calculations. Thanks so much.

 

[IceStationZebra]

First you need to know what the design requirements are for your area. In the USA I believe the safety factor is 4:1 with a test load of ~150%.

ISZ

 

[kerstinne25]

my boss had asked me to use a safety factor of 5.

 

[Ron]

kerstinne25...go online and find the OSHA standards for construction. There is a procedure in there for sizing and calculating loads on slings and spreaders.

 

[rb1957]

following a procedure will get the job done, reading a strength of materials textbook will teach you why it's done that way.

 

[SnTMan]

kerstinne25, get a copy of ASME BTH-1. Its fairly inexpensive. And study your strength of materials textbook as well.

Regards,

Mike

 

[metengr]

My problem, i really don't know where to start my design and calculation. please help me. They need to see the actual calculations. Thanks so much.

Note - this statement alone means STOP, step back and explain to your boss you need outside design expertise for the calcs. This task is critical and if not done correctly by you somone may get hurt.

 

[boo1]

ASME B30.20-2003 20-1.2.2
"The load-bearing structure components of a lifter shall be designed to withstand the stresses imposed by its rated load plus the weight of the lifter, with a minimum design factor of three, based on yield strength of the material, and the stress ranges that do not exceed the values given in ANSI/AWS D14.1 for the applicable condition. ....". SF for lifting eye is required to be 5.0 min.

Analysis or actual max working stresses must be determined based upon working conditions including impact or other factors pertinent to the application. Actual max working stress must be equal to or less than the allowable stress.

In the US the following may help guide you:
ASME BTH-1-2008 Design of Below the Hook Lifting Devices, Chapter 3
ASME B30.20a-2003 Structural and Mechanical Lifting devices. Section 20-1.2.2 Construction
CMAA crane requirements
AASHO 1.6.17
Steel Construction Manual-AISC
Occupational Safety and Health Administration (OSHA) 29 CFR standard 1926.753(e)(2) and 1926.251
American Society of Testing and Materials Specifications A391
Naval Facility Command NAVFAC-307
American National Standards Institute, "Below The Hook Lifting Devices"

 

[RossABQ]

I agree heartily with Metengr! Don't be afraid to tell your boss you want to shadow someone experienced with rigging designs for at least a couple of designs (assuming they may need further designs in the future). Peoples' lives could easily depend on your design!!

 

[NomLaser]

Personally, I would go through a rigging supplier if you or your company doesn't build rigging equipment. You might try The Tway Company, I have used them in the past for custom rigging components.

http://www.twaycompany.com/

 

[MiketheEngineer]

As mentioned - go buy one

 

[Pressed]

That might be standard unit, we have one a bit longer and got it from The Caldwell Group, Inc.

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