Nils Kristian Bakken

Problem Calculating lifting beams

Discussion created by Nils Kristian Bakken on Dec 5, 2007


I'm trying to calculate a spreader type
lifting beam, but I can't seem to get it quite right.

My problem is that the lifting beam is not
fixed in space in real life, so when I fix it somewhere it will not
give a correct result. The best way I have managed to solve this is
when I remove half the beam and use a fixed restraint in the middle
of the beam. Then I use bearing load on the top pad eye and bearing
loads on the lower pad eyes, but this will bend the lifting beam
and I know for a fact that this isn't correct.

I've also tried to use hinge, fixed and
bearing connector on the lower pad eyes, but since the lower slings
are angled outwards this will not give a correct result.

I have calculated the beam manually and know
that it's good enough and is designed correct.

Does anybody know a good way to solve this?