Seeing Double? Reinforcement Changes New to 2014
No, you’re eyes aren’t failing you – that really is a double mat of reinforcement in the manure pit wall. Why, you ask?
An explanation of the current state of building codes in Ontario provides the answer. As you probably know, farm buildings in Ontario are governed by the current Ontario Building Code (OBC) and the 1995 National Farm Building Code (Farm Code).
Until recently, the OBC simply referenced the Farm Code for all farm buildings. In 2006, this changed. A section was added to Part 4 (structural) of the OBC to state that, among other things, manure tanks must be designed using 32MPa HS concrete. However, the 1997 OBC and 1995 Farm Code were still applicable.
The 2012 OBC takes things one step further. It states that all manure tanks must be designed to Part 4 of the current code. Part 4 of the current code references a more recent version of the CSA standard for concrete (CSA A23), which requires all walls greater than eight inches thick to have a double mat of rebar. The older CSA standard required a double mat of reinforcement only for walls greater than ten inches thick.
So, what does this mean for you? Well, if you are constructing a manure storage tank, chances are you’ll be looking at a higher cost – the cost of additional reinforcement, plus the labour to tie it. The upside is that a double mat of reinforcement should reduce the likelihood and severity of cracking in your tank walls, resulting in a greater life expectancy for your tank.