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[Impact]

Got an interesting lift Monday.
Catwalk and conveyors over four grain tanks. Estimated weight: 18,000 pounds. Two lifts about 95 long each. Height is about 85'. Radius is about 45'. Power lines on one side, ICC railroad on the other. Just enough room to clear both.

Question for the riggers. Planning on a tandem lift. A 50 ton and a 60. Planning on using 20' shake out hooks. Probably two pair on each rig. The catwalk is designed to span about 35'. We'll be lifting 85-90'. The catwalk is about 8' wide. Eight points of attachement, four on each rig. I'm not comfortable with 2 lift points on each rig. I think the catwalk will bend and bow.

My question. Will all eight pickup points keep equal weight if the operators keep the thing level? If one gets ahead of the other, will they keep eual weights?

Oh, one of the operators has about 4 weeks experience. But, I plan to be there and talk him through it one move at a time.

 

[qball]

impact, dual picks are a pain. throw in a green operator, and you are buying trouble.
i would avoid using shake out hooks. go full sling/shackle to give a positive engagement to the load.

 

[willie59]

I agree with q, slings and shackles. Shakeout hooks are for sorting, I'd prefer a positive latchup with this one.

Question: why not four points of attatchment, each end of catwalk? If it's designed to span accross appx 35', why would it sag from each end rigging attachment? Seems it would sag once fitted as a bridge catwalk if that's the case. Am I missing something here?

 

[Tiny]

We use rolling blocks to keep the tension or weight right.

 

[heavylift]

shake out hooks... will come out if they get enough slack... you can use shackles instead of the hook... just wire it up out of the way...

the rolling blocks will work... if you have the 40' chokers and the proper blocks...

For high lifts we have marked the tag lines with paint... the first 20' or so doesnt need painted... then we mark them every 2 feet...with 10' marked a different color.

The thing is people have different depth perceptions... one guy sees level the next guy may think his end is low or high

 

[Impact]

I agree with q, slings and shackles. Shakeout hooks are for sorting, I'd prefer a positive latchup with this one.

Question: why not four points of attatchment, each end of catwalk? If it's designed to span accross appx 35', why would it sag from each end rigging attachment? Seems it would sag once fitted as a bridge catwalk if that's the case. Am I missing something here?

You guys are right. These aren't actually shake out hooks. My bad. Each crane will have 2 two cable 20' slings. Each sling will be clevised to the load. Each leg of each sling will be attached basically where the bridge bears on the supports or towers.

 

[Impact]

We use rolling blocks to keep the tension or weight right.

Even though I don't know what "rolling blocks" are, it sounds like a good idea.

What is a rolling block?

 

[heavylift]

snatch block is another term...

 

[liebherr1160]

Snatch blocks..= rolling blocks

Id be more inclined to rig with 4 ..two on each crane..

Say your catwalk is 95 feet long ?

with a single or double splice plate's?..how is it installed ..any bracing from the bottom of the walk to the silo..If so ..where that bracing is ..is where Id be putting my rigging ..

If not
This is how i would look at

If the load is symmetrical ..just even distribution of the weight from one end to the other ..

at 95 feet long ..30 feet in from each end Id hook up two legs for each crane..theory is ..you have effectively and evenly cantilevered the middle from the ends ..and picked a relative balance point of 1/2 of the load..
The only problem with this ..is that now you have moved both cranes closer together any off level operation will transmit the load down hill more quickly...loading up the crane that's behind faster..everybody get a game face,


(Now that you have a new guy ..a pair of digital fish scales and a 24in piece of 2 inch round stock is a good way to show him up front how the loads change when it goes out of level or when you change the pick points on one crane on the same load ..useful theroy in practice)

Once the load goes of level on two cranes the one down hill is going to get the load..
It can be neutralized ..but the amount of rigging and fore planning ..plus fabrication ..its not worth it ..

Perfectly honest brother ..Id have two well versed guys in the seat ..and an observer sitting back a few 100 feet to watch the bubble keep it level via radio to the two Op's untill it got close enough that the connectors can take over signalling and connect it ..just make sure the observer knows his job is done and a new man is taking over up top ..

 

[heavylift]

this is a crude diagram

as the load is tilted slightly... the chokers will roll thru the snatch blocks ... keeping the tension equal on all the chokers

the snatch blocks attach to the cranes' hooks

still keeping them as level as possible is the best... if you don't have a good visual on the lift... marked tag lines are the best way to keep track of the lift... I may take 4 lines.... 2 as tags and 2 as markers




this method could also be used to stand the catwalk on its' end

 

[Impact]

Wow. I've missed all these posts. Great posts, and great help guys. I'll have to remember the "snatch block" idea. I'd have to say that is the Correct way to do it. We didn't do it that way, just because we didn't have quick availability of all the necessary rigging.

It went well (nothing tore up and nobody died). We all had radios. Like Liebherr said, I put a spotter back 100-200 feet away to help us keep it level. The first one was more tricky. This first crane was set between the load and the point it would land, just because of the site. The second crane was behind the load when we first picked it up. There were electric cables (secondary low voltage, not primary lines) and guying cables for other structures. We had to lift it 60' or so before we could work the load around the first crane's boom.

The second pick was much more straight forward. Simple winch up, boom over, winch down.

All in all it went really well. The second pick seemed to deform the catwalk a bit, but it straightened out once it was set in place.

 

[Impact]

OH, the 60 ton crane had a capacity of about 50% greater than the 50 ton. So, first time we lifted it, we each had 8500-9,000 pounds. Set it back down, moved the rigging a bit, and we picked 10,500-11,000 on one, and 7500 or so on the other.

After we were finished, the new guy was grinning like a chit eating possum. He was proud of his-self.

 

[liebherr1160]

LOL

Operator probably had a woodie a cat couldnt scratch to!!!


Glad to hear it went well!:drinkup

 

[Impact]

Knowing how you guys enjoy photos, thought I'd add a few.

This is a support tower we built in our fab shop. We're raising it 42' at a time. We've got 1-1/2 42' sections up in this photo. We started off with a 50 ton crane and a S-85 Genie boom. We quickly ran out of crane boom and man lift boom.

 

[Impact]

This next photo show stacking with two cranes, the new 60 ton and the 50 ton. also I came up with a 120' JLG man lift from our good buddy Atco. This complete 84' tower and all 5 bucket elevators stacked inside.

 

[Impact]

Heard about the floods around Nashville etc? Well, that water flows down the Cumberland and Tennessee Rivers into the Ohio, and eventually into the mighty Mississippi. The Mississippi is full, and makes the other small rivers and stream drain slowly. So, here's my job site partially under water. Half of our site was on higher ground, the other half on low ground. We never missed a days work.

The pit you see is 18' deep. It had about 14' of water in it, and a few snakes.
The round foundation is 105' in diameter and 8' tall. We managed to keep compacting sand.

 

[Impact]

We weren't able to compact sand in the first & second photos. But on one of the other tanks we kept forming concrete on the higher ground.

 

[Impact]

Looking down from the JLG. SCARY and I've climbed steel all of my life.

 

[Impact]

Flooded job site and surrounding areas.

 

[Impact]

Stacking the third 42' section.