need help on project- not sure where to post!

[huskyfan68]

Been banging head against wall and was hoping to get some suggestions here-(not sure if it's even the right place- but I will try)
I've been tasked to help with a prop for my local high school's marching band. We had to construct a large, wooden ramp for them to perform on as part of the show. The ramp is about 38' long by 8' high at the top (yes- it's large)- we had to construct is as (3) 12' sections to move it since it's heavy- Here is the issue- Once the large ramp is on the field (Astroturf)- we need a way for it to move (side to side and spin around ) during the show- Right now, we have 10 boat tongue trailer wheels on it since they rotate 360 deg and can be cranked up and down- the issue is that no matter what we try- one/two of the wheels will "dig in" to the turf or grass causing undue stress on the frame (making it hard to push)- I'm looking for other suggestions on how to best move this beast more easily while on this surface (we even tried large furniture movers to make it "slide" but the weight caused it to not slide that easily.....)- I will take any suggestions

Thank you very much and sorry if this is not the correct place for something like this- I don't know where else to go........

[PinkertonD]

Welcome to the forum and yes this is an OK spot to ask this.

While a commendable project, I am terrified at the concept of something this big AND carrying humans, being designed and built by a non-Engineer. This is a frightening statement "for them to perform on."

You have no idea of the dynamic (movement) loads being imposed by a large bunch of people on that ramp.

I strongly suggest you get qualified Engineering help to design this. Ask around in your local area and I am sure you will find a structural Engineer willing to do this for free for the school.

If you insist oon proceeding on your own, then I suggest you tell the school Principal to ensure their liability insurance is set up to cover a mega-multi-million dollar payout for injuries.

The Engineer will be able to tell you how to easily solve the rotation and movement issue. But I will NOT be divulging it here to assist you in this insanity. Please listen to the voice of reason.

Google this...

stage collapse

...and be VERY concerned for your school and band members.

[huskyfan68]

thanks for the feedback and let me clarify. this is not for the whole band to stand on- only a few will be on there at a time. it it made very sturdy and has safety rails on the side. it's only designed for a few to walk up a few feet and play a solo and walk off..... hope that helps and I will inquire with an engineer- thanks

[PinkertonD]

OK, that sounds a lot safer than the entire band. I can only go on what you tell me and when you said, "for them," I was left to assume "them" to be the entire band, a number of souls as yet unknown to me. Engineers are sticklers for accuracy in all things especially communications.

Now, given the lessened load I feel a little better about suggesting casters such as the following link. Weigh all of the stuff to be moved then divide by 200 to get the number to purchase. I use 200 even though they are rated at 300-lb as it is never a good idea to operate anything at the maximum.

http://www.harborfreight.com/10-inch...ter-38944.html

[huskyfan68]

Thanks again Pinkerton and sorry for leaving out details..... the issue with using wheels in general is that they tend to "dig in" to the surface- when they dig in a little- then you have to "kick" them (So to speak) into the direction you want to go.... I was trying to find another way for it to slide without having to deal with the wheels turning in a direction you don't want.... I'm wondering if old skis would work.....or some other type of material that will slide easily under the weight (thats the tricky part) - I can't seem to come up with a solution to prevent the wheels from digging in (even though they are the easiest to use when moving)- thanks again

[PinkertonD]

without having to deal with the wheels turning in a direction you don't want

Did you read the description? They are 10" dia. x 3" wide pneumatic tires. They will roll easily over your astro turf.

Skis do not slide on snow, they slide on a thin film of water between the ski base and the snow. The weight of the human, the shape of the skis a natural phenomenon all take care of the "sliding" effect.

In my humble old opinion, wheels are going to be your only option. The trailer jack wheels you have are way too small in diameter to roll over a rough surface. I also suspect they are not mounted perfectly vertical and solidly mounted so they cannot lean at any point.

Any caster device will insist on the swivel-axis being perfectly perpendicular to the plane on which they must move. They must also be rigidly supported to keep that axis perpendicular at all times. If they are not, then they will go where they want to, to a large degree.

What I have suggested will work if your work can correctly hold and maintain them in a good working position. By all means investigate other options such as skis, but order the casters while you are wasting time with the other things as you will have to come back to wheels.

You could of course use a a solid base, skirt and blower for a hovercraft approach. Also, a thousand small down-facing jets of water might also lift the platform, but for economy and simplicity caster wheels are it.