After the plumbing phase, comes the steel installation. Steel is used to reinforce the concrete in the Koi pond. Although concrete has great compression strength, it has minimal tensile strength. Steel bars, (or rebar), which can withstand high levels of tensile stress are used to create a framework within the concrete to add strength under high levels of pressure from the water within the pond. Using steel in concrete is known as reinforced concrete.
The general rule of thumb is to lay the rebar down one way, 12" apart, and then lay it down perpendicular to that, also 12" apart, so you create a 12" x 12" grid. This grid is commonly referred to as either a 12 on 12 grid, or 12 inch on center grid. Places that are more weight-bearing, such as waterfalls or deep areas in a pond, they will use a closer grid, such as 6” x 12”, or 6” x 6” to increase support. Rebar usually runs in 60’ pieces. If the bar is not long enough, usually you take another piece, overlap the existing piece by 3’ or 4’ and continue on, as shown in the picture to the right.
The Rebar is bent using two tools that look similar to crowbars, but have 3 teeth attached to the end, which grab and bend the rebar with ease. The rebar commonly used is #3 steel, which means that it is 3/8” in diameter. If there are higher weight-bearing areas, sometimes a stronger steel will be used such as #4 (4/8” thick) and so on and so on. The rebar follows the contour of the Koi pond that was dug during the excavation process. When the rebar reaches the top of the Koi pond, it is bent 90 degrees at the center of the form to give reinforcement in the bond beam. The rebar coming up towards the form should measure approx. 9” from the form.
Once all rebar has been installed, it is lifted on to 3” concrete blocks on the floor and walls of the Koi pond. Shotcrete is poured 6” deep therefore the rebar is centered in the concrete. If the rebar isn’t set in the center of the shotcrete, the structural soundness is much weaker.
A solid team of steel workers can complete an average Koi pond in a couple of days. This includes all regular 12 inch on center work, and any other special work that needs to be done. Once all rebar is installed, it is time for electrical work to be done
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You Save: $300.00