Crane Side Thrust Loads

[B.Fallah]

Hi guys.
I've been working on a design for overhead cranes, and I have some questions about side thrust forces:
1. Why does a radio-controlled crane produce two times bigger side thrust forces compared to a pendant-controlled crane?
2. For calculating side thrust forces, there are two approaches:
1. Based on AISC, you simply consider it as 20% of (lifted load + Trolley Weight)
2. Based on other references like CISC and AIST, you should consider the greater of:
1. A percentage of lifted load given in tables based on crane type
2. 20% of (lifted load and trolley)
3. 10% of (lifted load and crane weight)
In some cases, the second approach results in much bigger loads, so what should we do? stick to AISC or use the bigger values?

 

[Klitor]

Just for info, real values that I get from producers of cranes are at about 13% to 15% of lifted+trolley

 

[canwesteng]

How would a crane producer be able to determine this? Are they installing load cells at their customers installations?

AIST is for mill cranes. The 10% of total load will give some allowance for lateral forces from misalignment of the rail. The correct code would depend on where you are located. There are also Eurocode guides for crane lateral loads as well, that consider even more cases.

 

[SandwichEngine]

The difference in load based on control type is due to speed. Pendant cranes go as slow as a man can walk. Cranes controlled from a control room (radio) go faster and therefore create a larger dynamic load. Cab cranes go even faster and therefore have even higher loads.

These days most pendant cranes are radio pendant where instead of having a long cable hanging from the crane you have a remote control but they still go as slow as a man can walk and can be designed for the lower forces of a pendant crane.

 

[B.Fallah]

The difference in load based on control type is due to speed. Pendant cranes go as slow as a man can walk. Cranes controlled from a control room (radio) go faster and therefore create a larger dynamic load. Cab cranes go even faster and therefore have even higher loads.

These days most pendant cranes are radio pendant where instead of having a long cable hanging from the crane you have a remote control but they still go as slow as a man can walk and can be designed for the lower forces of a pendant crane.

That totally makes sense now. thanks a lot.

 

[B.Fallah]

How would a crane producer be able to determine this? Are they installing load cells at their customers installations?

AIST is for mill cranes. The 10% of total load will give some allowance for lateral forces from misalignment of the rail. The correct code would depend on where you are located. There are also Eurocode guides for crane lateral loads as well, that consider even more cases

It's good to know the philosophy and reason behind these rules. could we say that the values considering "lifted Load" only are for the swinging of the lifted load while moving?

 

[B.Fallah]

Just for info, real values that I get from producers of cranes are at about 13% to 15% of lifted+trolley

Thanks Klitor. But I've always wonder where these values come from. I think there may be some practical methods used by the manufacturers for side thrust evaluation.