Cincerblock and concrete

[karimwassef]

ok. due to my natural discomfort with concrete, I've decided to simplify and go to mediums I'm more comfortable with. I framed out and installed my in-wall tank and I have 2 x 100 gallons tanks suspended (no supports underneath) on a 2x4 frame with plywood bottoms and 3/8" screw rod into the ceiling joists...

so - since I'm starting from scratch - all I have is a steel frame and a concrete floor (TBD), I decided to go with wood. It's the only medium cheap and strong enough that I'm comfortable with.

so....















The 2x12 joists will do the heavy lifting. The span is 18' with a center brace at 8' from the right end.

I had to raise the reservoir even further to get the front joist to clear the surge containers (getting them in position is possible now).

The platform for the surge tanks will only need to handle two tanks - so that's 650gallons = 5500lbs. The platform is 3'x8' and I've doubled up on the vertical studs.

Yes - the center wood support will be in water and so the whole thing will be epoxied before assembly, and yes - that one section will not be bolted into the concrete foundation.

And no more concrete sump - going with large plastic basins.

It was a pain feathering it out to this level, but I felt it was necessary... even though the project is still months away.

But now I can calculate the load on the slab and get back to making sure it can handle the weight without cracking.

[karimwassef]

I still need to add some of the cross-beams and skin it with waterprood drywall/toughrock or cement backerboard

[karimwassef]

and in case anyone wants to know what the containers are:

https://www.ntotank.com/1300gallon-n...-tank-x8829122

https://www.ntotank.com/625gallon-ac...-tank-x9873974

https://www.ntotank.com/400gallon-cr...-tank-x6907055

https://www.ntotank.com/325gallon-ac...-tank-x8666939

and still considering this for the raised reservoir... so cheap, hard to resist: https://www.ntotank.com/200gallon-cr...-tank-x5272244

and it would reduce the burden on the frame (200 gals instead of 500)

[karimwassef]

the structure's frame is designed to handle 90mph winds so the steel/glass panels are 4' x 6' on the sides (for reference)

[karimwassef]

I had to go back to the drawing board after completing the wood frame. The loads were still too high.

So - I increased the cinderblock support under the display tank and changed the frame into a box room with 8 ceiling joists (2x12s) that span the 20' room. I also added headers, cripples, noggins and double studs where I wanted more strength. I put the "submerged" center supports in a plastic box with concrete and epoxy to seal. I don't think it's necessary, but I decided to keep it in.

The weight is now distributed across a much larger surface area and the load stresses have all dropped under 10psi. There are only two heavy spots - one under the display tank back (where the in-tank surge tanks are). This is ~ 10psi. The rest is 6 psi or much lower.

With a highly localized load region, I'd like to throw out an option for a thicker slab in the middle (18" thick) while keeping the rest at 6"...

Erica - please look at my framing - I'm deep in your territory here.

Oh - the 12" slab first quote came is at $20,000 - for the slab only... no structure.

So - picture to follow:

[karimwassef]

Here's the view from underneath... the green wood is going to be tied to the concrete slab.
The sides will be screwed into the steel frame or connected to sides that will be.



I know this is hard to see, so I'll try to take more shots to make it easier to see errors or improvements.

here it is without the plywood platforms:



and this shows the steel frame around the room:



and here it is skinned with 0.42" 30x60 Hardiebacker board:





and here's I get from a loading:



with the concept of the different slab thicknesses:



the slab is 6". the skirt is 2' (30" total) deeper and 1' wide. the thickened area is 1' deeper (18" total) in the middle.

so here's the "proposed" thickened areas:

[karimwassef]

I realize it can be exhausting to look at all this - (imagine going through the design and drawing)... I really do appreciate the help.

[karimwassef]

Here's the little plastic bucket I'm planning of filling with concrete and epoxy so the wood studs can have central bracing

https://www.ntotank.com/30gallon-che...-tank-x4370287

[karimwassef]

so.. since my highest pressure (except one region) is now <868 lb/ft2 (6psi), I should be able to get away with 6" thickness...

The two back legs of the tank are at 1360lb/ft2.. that would require 16", but it's a pretty small region. Maybe two pillars right there would be a reasonable solution?

(that assumes that the wood framing is able to distribute the weight as expected).

so - maybe:

[Clowning_Around]

Based on your graphic out looks like your using what's referred too as a pre-engineered metal building. If thats the case I would not connect your framing to it, instead I would leave it independent right inside. P.E.M.B. are designed extremely tight with little safety factor right up to code minimums with high deflection numbers (like L/180 vs L/600). It's for these reasons why they are so efficient and economical, especially for there intended purpose. If you connect your structure, and its designed such that it can take the load it will likely still have a lot of movement which will telegraph through and given the nature of glass could be a bad thing quick. For example this is a common challenge with these type structures when brick veneeres are desired, the P.E.M.B. engineer says its fine because it meets code minimums for (safety) but doesnt meet the architects minimum needs (aesthetics) so the brick cracks (aesthetics) from movement but doesnt fall (safety). My point is these type of structures are designed to resist minimum wind loads etc, but that doesnt mean they wont have a lot of movement doing so, so don't tie into the shell rather remain independent with you critical structure.


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[karimwassef]

Actually the steel frame is prefabricated but the wind and snow load are custom inputs. As I increase wind load, the number of vertical and horizontal steel members changes and so does the cost.

The current structure is designed to 90mph loads but I've run it up to 150 to see what changes. It's also not "cheap",

Current design is ~ $13K

https://www.versatube.com/design-your-own/?id=151529

I've been looking at others who have put them up with videos on YouTube and researching bad reviews, etc... so far, it looks like a decent product.

Basically I built a wood room inside a steel room. Both should be solid... but I don't have to tie them together, I guess. Need to give it more thought.

As far as wind loading... the weather in Dallas is from the south, so 95% of the time, it's coming straight north facing the front glass doors on the smaller 25' face. This was intentional so the long axis of the structure lines up with this flow.

[karimwassef]

Any feedback on the structures or slab? I love autocorrect.

[karimwassef]

I can increase the snow load to 75lbs and the wind load to 175mph

https://www.versatube.com/design-your-own/?id=153039

It's $5K more and the frame weight has increased too to 5700lbs but it's distributed over the perimeter so it should be fine. The panels go from 4' x 6' to 4'x4' (need to double check final dims) so that's a little less light.

it may be worth it. I'll have to redraw the structure.

[Sharpimage]

You are going to need a building permit to build this. Which means an architect and engineer to design it. You could run the numbers a thousand ways, but in the end an engineer is going to have to stamp it and put his name on it. Which means he will design it the way he wants. You have a good start, but you are wasting your time trying to fine tune it at this point. You have the basics correct, bit the engineer will have the final say. Just trying to save you some time. It is clear you have put in quite a bit.

[Sharpimage]

Also, just for reference, the safety factor in s Florida is typically 3. So your loads and requirements go way up

[karimwassef]

Actually, since it's not a residential area and it is more than 10' from the house, it needs a detached garage permit only. And since the garage comes pre-engineered with documentation for the city permit, I really don't need anything else. The slab will be built to the engineering drawings from the garage manufacturer or greater.

Check out their site... it's great!

There's no permitting for the ability to hold an aquarium or tanks inside it... that's all part of my private use of the garage. So the only variables are (1) whether the wood framing and cinderblock will carry and distribute the weight of the tanks to the slab and (2) if the slab is solid and will support the load.

And those two are what I'm looking for feedback on at this point

[Sharpimage]

Ok. Wood is not my forte, so I can not comment. Seems like a lot of weight for a wood structure though.

[Clowning_Around]

Originally Posted by karimwassef

Actually the steel frame is prefabricated but the wind and snow load are custom inputs. As I increase wind load, the number of vertical and horizontal steel members changes and so does the cost.

YEP same difference

The current structure is designed to 90mph loads but I've run it up to 150 to see what changes. It's also not "cheap",

yea 90, 150 etc but at what importance factor and deflection value? Meaning 90mph hits building it racks building 2 feet out of plumb that can be considered ok with some criteria bit thats not what you want obviously.

And 13k while it may sound like a lot of money, for a steel structure this size it is cheap, price it with conventional steel...



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[Clowning_Around]

I forgot to mention the 13k includes the engineering for this type, so with regard to my comment you have to compare the conventional steel and the applicable portion of the engineers design fee to get a true apples to apples.

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[Clowning_Around]

Originally Posted by Sharpimage

You are going to need a building permit to build this. Which means an architect and engineer to design it. You could run the numbers a thousand ways, but in the end an engineer is going to have to stamp it and put his name on it. Which means he will design it the way he wants. You have a good start, but you are wasting your time trying to fine tune it at this point. You have the basics correct, bit the engineer will have the final say. Just trying to save you some time. It is clear you have put in quite a bit.

I agree work on your concept and drive how you want big picture things done and discuss them with your designers, they may even propose some alternate ways that save money adding to the value of their involvement. Just nail down the aspects that are really important to you like x clearance under a tank and not so much about how thick a slab is etc..

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[karimwassef]

Ok. So going through the last few weeks, I've changed the support structure to reduce the load stresses by a third. I've redesigned the tank flow and given up a foot of tank (140 gals) to do this. I've also worked out a conventional wood structure that is used to carry the weight of a house. The ceiling joist, stud and rafter design is used in my current house and carries the complete weight of two floors and the roof.

If it wasn't for your help, I would still have an unwieldy and overstressed design. So - thank you.

So - I'm an engineer myself and I've built and helped build large projects before. I tend to design, analyze and calculate way ahead of the execution date to get as much input and learn as much as possible.

I haven't actually built my house with my own hand (it was a custom), but I worked with the engineers, architects and the building contractors to get what I want. I designed it on a blank page starting with easements and build line restrictions (just as I'm doing here). Having gone through that and helped others with actual building, I'm not easily intimidated. While the architect gave it his blessing, and tweaked a few variables- my design was basically unchanged.

I am personally disappointed by contractors and firms who are willing to charge exorbitant profit for work that I've already done. I'll continue to look for a structural engineer I can trust and work with, but I'm not giving up.

[karimwassef]

Now - back to the design. (just needed to get that last bit off my chest)

On the slab, assuming that I have calculated the pressures correctly, would that slab thickness support the loads? If not, I'll go for the individual pillar designs. I just thought the modulated slab thickness would be cheaper since I got the heaviest load in one zone, but still made it uniform.

On the pillars- these have a foot diameter at the top but the load "point" on the slab is actually made up of 4 cinder blocks side by side ~ 30" x 15". Would I need two pillars for each of these 4 block regions or would one work?

On the framing and loading: there are five loads:

1. The tank: the tank is unusual because it has a load on one side that is substantially higher than the other. I made the extreme assumption that the blocks there will need to support that load (worst case). This is because the weight is actually passed through the sides to the tank floor (3" of stacked plywood) onto the blocks below. I am supporting it with 8 cinderblocks side by side. I think this will work - but that's one concern.

2. The surge tanks (drums). I'm using the same framing construction I used in my current tank (4' x 8') for this narrow stress point (3' x 8') with 2x4s and plywood. It's close to the ground and tied into the green lumber (on two sides) that will be attached to the foundation. I do need to leave a wide opening (5') for the settling tank underneath and that's worrisome, but with horizontal 2x4s on their side at the top, I think it'll distribute fine.

3. The raised reservoir. This 500 gallon tank is where I went with heavy framing support that should hold up a house. Traditional 2x4 studs with 2x12 joists should be more than enough based on my experience. I'm using 4 (! )joists to span the 20' and then 2x4s at 16" or less to bring the weight to them, with a plywood base on top. I think it's overkill actually but I'm open to feedback. The "leg" in the water is more overkill and I'm hoping Erica or others will say it's not needed.

4. The raised IBCs are similar weight and height so I used the same design as the reservoir. I did put these almost back to back so the weight distribution in around the thick slab area.

5. The sump is now all plastic containers on the concrete floor. The weight distribution is proportional to water level and at 20", it was minimal... anyone with a tank in their house is doing more, especially if they're putting it on a stand with feet.

[karimwassef]

on attached wood to steel. It may be that the steel deflects the wood, or that the wood stabilized and supports the steel. The steel is skinned with steel and has ribs between the 6' sections so I don't think there is a foot of deflection ( )... but there will be some.

I need to have an internal wall anyway, so the wood frame was going to happen all along. The only question is whether tying the two together is a net stabilizing design element or if it will just transfer the wind live loading and create dynamic stresses on the wood frame that's holding up the raised tanks. Given that the steel is there to protect from the elements, and the wood frame supports the guts, I'm ok allowing the two to move independently - like a snail with a hard shell that moves independent of the soft squishy parts instead - except the soft parts have a skeleton too.

[karimwassef]

maybe I should start a new thread for the wood frame? The display tank is the only part with cinderblocks now and the only concrete is the foundation.

[karimwassef]

here's a nice tool for calculating what 2x12 joists can handle

http://www.awc.org/codes-standards/c...tware/spancalc