Calling all engineers

“70.5%, I might actually have a life outside of work after all!
I'm sending this out to everyone here in the office.”

“65.4% Ah Jeez, I'm an engineering dork without even trying!”

“83.60 - what do I win?”

“62.92% Cute Quiz!”

“I guess my score proves it.

49.18%

"integral of your curves"? lol”

“so, engineers, did you fly thru the quiz? or take your time to really think each answer through? lol”

“Flew through it, is there any other way to take a test?”

“14.25%.....


Darn, I was trying for zero.”

“78% never realized there were this many engineers here- arent engineers the anti-enviromentalist? ive been thinking im half the enemy!

:p

later,
-nate”

“i also scored 49.18% - but my engineer husband scored much higher. i'm dorky by osmosis!”

“nate, i'm an environmental engineer. heck, i'm working on a preliminary design to remove sanitary sewer overflows to a river. i'm pro-environment!”

“Let's say I needed to build a 50-foot tower at home. Something more substantial than a skinny aerial/antenna tower. It would be used to support various solar equipment and to take in the view now and then. Requirements:
- support 1500 lbs at the top in equipment, platform floor, railings, 2 people
- platform would probably need to be 4' X 4'
- the use of guy wires to reduce the footprint and cost is assumed, if that is the best route
- the weight of cables, pipes, and a permanent ladder could be supported by a central support/pipe, taking the weight off the main structure, if that is best

Anybody know of a back-of-the-envelope cost figure for something like this?”

“4'x4' is awful small. What are the expected weather conditions in this area. You will need to factor in things like wind/lightning etc.

You might want to check on any zoning or related requirements (may not apply). Finally do you want a Pole structure (wooden) metal or concrete?

I think there are some metal truss construction kits you might be able to get.”

“1 million dollars (said while holding pinkie to side of mouth)”

“- support 1500 lbs at the top in equipment, platform floor, railings, 2 people

sounds like a gun turret to me...what are you trying to keep out, or keep in?”

“Will the mother ship be tethered to this tower?”

“The weight won't be the issue, wind or seismic will be. 4x4 is tiny. You don't have any leverage to resist overturning. You'll have to guy it. Be sure what you guy it to goes deep. Look into Chance helical anchors. They have about a 10k uplift resistance. They run about $1500 each and you'll likely need 2 at each guy. This has more to do with resisting loads in different directions than a capacity.

I don't know cost.

You're local building official will/should require that this be designed by a structural engineer. I suspect his fee will be in the $2000-$3000 range, but that's a guess and will depend on where you're located.”

“See I wasn't that far off then. ;)”

“Tech....its okay we found the ticket that Kenny had for the Candy Store!!!! South Park Episode 612”

“XL - The equipment would be mounted all round the edge of the platform. The remains of hurricanes occasionally make it in as far as my place so wind loading is an issue. Zoning shouldn't be an issue since I'm out in the country and this would only be just above the tree tops. Material doesn't matter to me - cheapest is the best. Oh, and sorry, I don't keep up on South Park anymore. What was in that episode?

thrifty - "used to support various solar equipment...". Although if we encounter anarchy any time in the near future it would make an excellent defensive position. :-O

MarkO - that will be my next project. :-P

dayhiker - with the small 4 X 4 platform I figured a non-guyed structure could be an option if it is cheaper, since the footprint size isn't an issue. This would be like a fire watchtower, and I don't see many of them guyed. Granted, their platforms and therefore footprints are much wider. Little seismic activity around here, I'm nowhere near San Francisco! (zip 21053) So we're talking $15K just for what you mentioned, w/o construction costs or the rest of the materials. $30K+ minimum?? I guess I could put up one or two aerial-type towers, only if they could support the weight, but I DON'T do heights so someone else would have to do the maintenance. Initial installation would be a pain too.

------------------------------

You see, I have a fairly suitable ground-mount location on my property for the solar equipment, but its about 300 feet from the house. That's a long run for a low-pressure water system and low-voltage PV's. Its doable, but fairly expensive, and all below-ground. I could put a tower 50 feet away, which would only be a 100 foot total run, and mostly above-ground. I'm trying to figure out the cost/benefit of my various options. Looks like even with the long run the ground-mount option would be cheaper. I could install a complete PV and water system for about $30K. I guess no 360* star views for me.

Thanks very much for your inputs!”

“The forest service is auctioning off these fire towers. Successful bidders have to disassemble them and cart them away, but you should be able to get a good deal. I'd just leave the shelter off at the top for your purpose.

www.fs.fed.us/r9/auction/docs/fire/fire.htm”

“You Suck V, every once in a while you catch me off guard!”

“Oh... my mistake.”

“LMFAO, you almost got me Violin. Thanks for being the sacrificial lamb, BackSlacker.”

“Welcome to Tower 101.

http://www.ces-kcmo.com/pdfs/Tower_101.pdf”

“Firetowers are more like 14' square than 4'. The smaller footprint hurts you. You'd be better to build a bigger platform in area than to fight the overturning.

Seismic now controls most design in the east due to the change in building codes. I did a project in Salisbury, MD and seismic controlled.”

“nice one V, i was just thinking the other day that it had been a while.”

“More to think about and read. Thanks.”

“If you guy it you'll come out better. If I get time this afternoon I'll run a quick model to see how much it moves. I suspect unguyed it'll move close to 12" unguyed. It'll probably be more like 1" with guys.”

“What about with girls?”

“4x4 is kinda "no guy ish" if you ask me. You need something around 40x40 with Titanium tipped cruise missiles.”

“Teckntrek,

You could build the tower for a little over $1000 dollars. Go out and buy yourself some used scaffolding standard 5 X 5 should be good enough. Buy four galvanized scaffold bases. Four large anchor bolts with eyes about 4 feet long at least 1 inch diameter with large washers or plates. Sixteen anchor bolts with large washers or plates about 1 foot long 1/2 inch diameter. Enough guy cables, shackles, etc. Order a truck of concrete. Dig a footing for the tower base at least 2 feet deep and 2 feet wider than the tower base. You will need to anchor the scaffold bases to the concrete with the foot long anchor bolts. To set them, suspend them through 2x4's until the concrete sets. Dig 4 holes approximately 3 feet square and 3 feet deep, at least 1/2 the tower height away from each corner of the tower. Same thing here suspend the anchor bolts till the concrete sets. The engineers would probably tell ya to throw a little rebar in as well. Skip the pilings, unless you are building this in a swamp dey ain't necessary. Once the tower is erected you can weld the joints together if you like. The scaffolding will provide all the vertical strenght you need. Put the guys at the top and about half way up. Keep the guy lines tight and even. Paint her up real good to resist corrosion and you got yourself a tower for a long time.

Now you owe me $12,456 for my 5 minutes of design time.”

“Don't stand anywhere close to that thing when the wind blows and expect it to move a few inches if you shift your weight even a bit while at the top.

Pilings in swamps are to keep it from sinking. Pilings on a tower are to keep it from picking up out of the ground. Apples and Oranges.

With that said, you might be able to guy off a scaffolding platform.”

“LOL. I thought 4 X 4's were very guy-ish. 2 X 4's being the non-guyish option.

Anyway, bacpac's link lead me to some additional online research. Looks like there are pre-engineered self-supporting options for the height I need, at around $3K. Not including any installation costs. Wind loading and ice loading is factored in, but I would have to contact manufacturers to see if they can handle the equipment weight. At least I have a closer idea of what that route would cost me vs. the ground-mounted route. No neat observation platform though. Oh well.

Edit: just saw the scaffolding design. The check is in the mail, Bateauxdriver. Let's see if I can get it through the permit stage... (You want to do what?!? With scaffolding ?!?)
last edited: 2/08/06 10:12:53 AM”

“Pilings? This tower will require bell piers.”

“Bell piers are only appropriate in certain soil types. The bells collapse in sandy soil.”

“>:(”

““Don't stand anywhere close to that thing when the wind blows and expect it to move a few inches if you shift your weight even a bit while at the top.

dayhiker
9:54:20 AM
2/08/06

Hey Dayhiker if I ever inviute ya over to the abode keep in mind I did the construction and I live up in the air. Ya might want to sleep in yer tent a ways away! But seriously guys I work with hunters who build their deer stands this way. They actually make a little house up top. But only 20 to 30 feet up. A guy wire or two tied off to trees and no concrete. They call them Lazyboy stands. Many actually survived Katrina. If the scaffodling wiggles wear a harness!”

“That wouldn't scare me at 30' at all. 50' is different but it would need to be guyed. Also, some guy climbing a tower for deer hunting expects it to move a good bit. tech might not have that same expectation for his use. Also, the majority of hunting fatalities come from guys falling out of tree stands 8)

You still planning on Sipsey?”

“...Many actually survived Katrina. If the scaffodling wiggles wear a harness!”
Bateauxdriver
10:26:03 AM

Remember folks, Bateaux's area was on the good side of the hurricane that did not have the high winds of the East (bad) side.”

“Thats right Dayhiker Bell Piers in sand can become bell sinkers. Gotta have deep pilings in sand. Not to mention footings deep enough to prevent undermining. Next door to me is a 4500 square foot home built on a sandy hill which is old dredge spoil from the river. The house is shaped like a U with a pool in the middle of the U. I begged him to drive pilings and put in deep footings with tons of rebar. He didn't want the extra expense. I think one day the house is going to slide off into the pool. He has faith that the post tension slab will hold it all together. I hope he is right. First water leak from a pipe or the pool and we will find out.
last edited: 2/08/06 10:44:08 AM”

“You still planning on Sipsey?”

I'm gonna put everything I can into going. So far this year I haven't had the best of luck. I wanted to go to HPM's trip this weekend but the distance and the time I can be away from work just don't jive. I've scheduled vacation for the Thursday before Sipsey so we will leave sometime Thursday night and sleep at the trailhead in the van till others arrive.”

“I'll be in touch on Sipsey then. I'm hoping to have a side trip on Thur and will just crash somewhere convenient that night. It sounds like you're leaving when the boys get out of school on Thur so you'll be there around 10ish. I'll know more in a few weeks when I head out.”

“spirit coyote - why the angry face?

Bateauxdriver and others - I just remembered something that may change my situation some. The previous owner told us that the soil only goes 4 feet down, then its bedrock. Would any anchors/footers need to go down farther than 4 feet for something 50 feet high? If yes, I assume there are options to anchor into the bedrock?”

“Auger cast pile and drill and pour piling are very common east of you. From Gulf shores and east that's what they use for all the high rises. I did the foundations for a 22 story one about 2 years ago and it bunches and bunches of 16" shafts.”

“Rock anchors are pretty common. They drill a hole and then put an anchor in that is grouted into place. I assume the grout is an expoxy similar to how anchor bolts are grouted into existing concrete.”

“Uuugh! I've been on the bad end of that 16" Auger before. Nasty dangerous work. Dang cheap way to make a piling though.”

“Hey Bateaux!!!
You bringing the boys?
Forest Dump and what did we name the other?
LOL
Couple of great kids ya got there.
Everyone liked them.

You have to get them trained to cook for you.”

“Yea Stovie they are begging to go they miss you guys as well do I. Their names were Trip'n'Fall and Forest Dump. They do want to cook for themselves now. I bought a canister type optimus crux for them to use. They had a great year last year. We carcamped/backpacked for a week with Hyway and his girls in North Carolina. We hiked and mountain biked in Colorado, rafted the Colorado River, and some hikes around here as well.

Bama asked me last year to bring up a sack of crawfish for him to hike in with. I'm gonna seriously consider it. I boiled up a pot of blue crabs last week that were outstanding. Almost everyone was a select and they were full. Best of all they were free. An oysterfisherman that stayed with us after Katrina gave them to us. He lost his home but saved his boat.”