Crane ground pressure

[ait92]

A crawler crane 200t capacity with max lifting load of 30t at working radius 25m. How to estimate the induced ground bearing pressure when boom swing 0,45,90 deg.

TQ

CSK

 

[csd72]

You need to get the reactions from the manufacturer.

 

[ait92]

Dear csd72
The crane model is hitachi KH1000. The crane manual only indicate the average operating ground pressure, that is not the peak pressure.. The ground pressure will be greater towards the front of the crane with lifting load. Can anyone advise me how to get inform from the manufacturer?? website or email???? Thank

 

[Qshake]

Use the manual to look up the manufacturer and once known use the internet to find the company office phone numbers. Hint: Your last post indicates it is a Hitachi.

If you've ever had a statics class this should be a straight forward project, it's not rocket science.

Lastly, did you think the manufacturer doesn't want the user to ever see the maximum pressure? By keeping it to the average it is more conservative and safer for everyone involved.

Regards,
Qshake

Eng-Tips Forums:Real Solutions for Real Problems Really Quick.

 

[DRC1]

Some crane manufacturers will give you this information if you contact their engineering department. Otherwise you will need to get a copy of "Cranes and Dericks" by Shaperio. You will also need to get the broken down weights of the crane. These are listed sometimes under transport information. You will have to make educated guesses about the centers of gravity. Although not complicated, it does take a little time. Crane manufacturers provide limited information to compute actual track loads, making it tough to predict the response of adjacent strucures.

 

[ait92]

I have sent a mail to the manufacturer Hitachi before I posted this thread. But till now still no response from the Crane manufacturer. The operating pressure indicated in the crane technical manual is the total weight of crane divided by crawler tracks contract area. If a crawler crane is supported by a temporary steel platfrom, use this average operating pressure as shown on the catalog would underestimate the load effects on the supporting structure. I did a similar temporary platform design for a Kobelco 250t crawler crane, the response from Kobelco is fast and accurate....

 

[DRC1]

Option 2 (not as accurate as the other option, but will get you a number) Crawler cranes are rated at 75% of tipping or allowable boom stress. Usually the table diferentiates. Lets assume your controlling condition at your desired radius is tipping. Take your load and divide by 75%. This is THEORETICALLY the load the crane will begin to tip, so ground pressure at the crawlers will be 0 and the reaction will be at a third of the distance along the crawler. Thus you can solve for the reaction. Then you can find your actual overturning moments for your anticipated loads. From this you can solve for pressure distribution on the tracks. If it is a latice boom crane, changes in radius will not have a great effect on the restoring moment. This is not really the best method, but it is fast and does get you a number when you do not have a lot of crane information. I am sure a lot of people will point out several inaccuracies in this approach. I only use it as a last resort or for a order of magnatude number. The method in the first approach is a better method. If you do use this please be very conservative with it.