


Thread Tools  Search this Thread  Display Modes 
04072006, 06:48 PM  #1 
Member
Join Date: Apr 2006
Posts: 235
Rewards Points: 150

Concrete Columns?
I am building a deck using 8" sonatube 4 ft deep. I need to figure out how many 80lb bags of ready mix concrete to buy to fill each tube.Can you tell me how I determine this number. There are 12 tubes to be filled all together. Thank you.

04072006, 07:46 PM  #2 
Contractor
Join Date: Feb 2006
Location: Maryland
Posts: 62
Rewards Points: 75

Concrete Columns?
Well the formula for the area of a circle is:
Pi X radius squared which in your case would be, radius 4" or .34 squared = .1156 pi = (3.142) 3.142 X .1156 =.3632 .3636 X 4' of depth of tube = 1.45 cubic feet per tube 1.45 cubic feet per tube X 12 tubes = 17.43 cubic feet. How many cubic feet are in an 80 lb. bag of sacrete I have no clue, but it should be listed on the bag. If I were you I would get a few extra bags, it is surpising how much you can loose on the ground when filling those things. Tom Somebody check my math please. I have been known to order way too much, and way too little concrete. Just ask the dispacthers. 
04072006, 07:59 PM  #3 
Member
Join Date: Jan 2006
Posts: 104
Rewards Points: 75

Concrete Columns?
That sounds pretty good to me, but rounding your #'s off makes it a little off. I came up with 16.75404 cu. ft. I Would just say that it takes 2.4 bags per pier x12=28.8 bags. Plus whatever waste you want to account for.....
Bob 
04072006, 08:21 PM  #4 
Contractor
Join Date: Feb 2006
Location: Maryland
Posts: 62
Rewards Points: 75

Concrete Columns?
Too many decimal points for me Bob. :o
Thanks for the verification. Tom 
04082006, 06:08 AM  #5 
Member
Join Date: Apr 2006
Posts: 235
Rewards Points: 150

Concrete Columns?
thanks for you help, I will buy extra for waste like you said. What a great forum.

04082006, 06:33 AM  #6 
Member
Join Date: Apr 2006
Posts: 235
Rewards Points: 150

Concrete Columns?
after reading your reply, I was wondering why you used a radius of 4" wouldnt I use 8"? since the tubes are 8". I am not questioning your knowledge, just want to be able to figure this out on my own if needed. Thank you again for your help...

04082006, 09:56 AM  #7 
Contractor
Join Date: Feb 2006
Location: Maryland
Posts: 62
Rewards Points: 75

Concrete Columns?
8" is the diameter of the tube, 1/2 of the diameter would be the radius, 4"
Tom 
Thread Tools  Search this Thread 
Display Modes  


Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
Sleeve options for plumbing through concrete?  Bruce L  Plumbing  6  06142008 09:38 AM 
stone veneer formula  tom1st  Landscaping & Lawn Care  1  07082006 04:48 PM 
Need to expand existing concrete pad for A/C unit  miketegra  Building & Construction  2  07032005 10:27 PM 