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Propped Portal Frame

Propped Portal Frame

Propped Portal Frame


I am designing a propped portal frame at present. It has gantry cranes on either side of the central column. I am finding that the horizontal displacements at crane level are too high. The crane manufacturer recommends a tolerance of 10mm. Can anyone recommend a way i could keep the displacements at a minimum without having to increase the size of my members.

Many thanks   

RE: Propped Portal Frame

Its either change the size, or change the geometry somehow to increase the natural stiffness of the system.

RE: Propped Portal Frame

Have you used fixed bases on the columns? Make sure that your footings, anchor bolts and base plate are designed to limit rotation of the columns.

RE: Propped Portal Frame

Knee braces might help out if you have room or clearance for them.  X-bracing would be better.  I agree with jike, fixing the column base would help.  That means your footings will be 2-3 times bigger and connections will be bigger as well. Of course you can just use larger/deeper columns and beams if they fit.

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