Loads on structure under transport?

[sema79]

Hi everyone,

I am analyzing loads on a structure while it is being transported on a truck. This is a manufactured item that will barely be small enough for a truck transport. I know how it is planned to be positioned and held down. I will be using RISA 3D for an analysis. I would like to know specifically what kind of impact force to apply for bouncing up and down on the roadway. It seems like there would be a rule of thumb or a specification somehwere that addresses this. A coefficent to apply to the self weight would be ideal for a RISA static study. Does anyone know a reference or a rule of thumb to use? Thanks in advance!

 

[csd72]

If this is a concrete panel or item then be sure that they are not also expecting you to alalyse it when it is being lifted out of the form. The suction in the form can add quite a bit to the load.

More info on the item would be useful.

 

[sema79]

csd72,

It is a fiber reinforced composite structure for the power industry. No concrete at all. It will be formed in pieces and the assembled before shipping. It will be analyzed for lifting as well. My main concern is the forces that happen due to bouncing down the road.

 

[frv]

Look at the PCI Handbook as a starting point.

They address impact factors for transporting wall panels. It seems reasonable to assume something similar for your structure (Maybe bump it up some to account for the uncertainty due to the different material)

 

[Bagman2524]

There was a recent thread on this subject. I suggest doing a search. I believe the transport loads can vary significantly. Radioactive materials use something like a 2g lateral and 4g vertical transport load.

 

[dhengr]

Sema79:
The question you are asking is indeterminate, as is the math/stress solution if you can find/pick a “g” factor. They’ll put it on a stiffer trailer, or one with stiffer suspension, or they’ll find a larger pothole at higher speed on the next trip. PCI or trailer manufacturers may have some starting points for you. But, the rules of thumb you want may really be design of a good dunnage system to protect the most highly stressed, or vibration sensitive parts of the structure. And, you should have a feel for these locations from your basic snow, wind and lifting load calcs.

 

[dcarr82775]

I know an engineer who instrumented some trucks with accelerometers, place similar loads on the trucks to those being considered and drove around measuring accelerations. his concerns were more overturning at curves, but if your project is big enough this cost could easily be included

 

[rscassar]

I worked for company which fabricated steel buildings (20' wide x 75' long) with steel floor frames. Fixed to the floor frames was heavy electrically equipment. The floor joists were light gauge metal sections except for the joists which supported the equipment. These joists were rolled steel channels to help support the equipment during transportation. There was no calculations to show why this was required, it was just a rule of thumb for transportation.

 

[delagina]

This is common in Petrochemical. Shipping, Transporting, Lifting of Modular Structures. Additional 50% vertical and 60% of Dead for Horizontal as assumption if i remember it right.

Shipping and Transporting are different. They will use "truck bed" once on site. The bottom beam will carry all the weight instead of the column during transportation.