The following will provide basic facts about cattle guard forms. The information gathered is from first hand experience as a cattle farmer as I have installed both forms and traditional steel cattle grids.
What is a cattle guard form?
Unlike steel or pre-cast concrete cattle guards that are purchased ready to install, a cattle guard form consists of a polyethylene form whereby farmers use to cast-in-place their own concrete cattle guard. Unlike most concrete forms the cattle guard form stays in or above ground and is not removed or flipped after the concrete cures. The form comes pre-installed with 5/8″ fiber glass (GFRP) reinforcing rod. The reinforcing rod gives the concrete the added tensile strength to support heavier loads.
What is the advantages or disadvantages of a form?
The advantages of a form include:
- Light weight – cattle guard forms are light weight even with the pre-installed fiberglass the total weight is 150 pounds.
- Economical – most cattle guards especially constructed from steel are expensive. Cattle guard forms typically cost 40 – 50% less.
- Heavy Duty – Concrete reinforced with 5/8″ fiberglass rebar gives cattle guard forms a minimum HS-20 load rating or 32,000 lbs. per axle.
- Longevity – Concrete reinforced with fiberglass rod will not rust or oxidize like steel rebar and will typically outlast steel cattle guards.
- Safer – Unlike steel piping concrete beams are like walls leaving no voids where cattle or horses can trap their hoofs.
The disadvantages of a form include:
- Unlike a finished steel cattle guard a form will require concrete to be poured and time to let cure
- Concrete is typically twice as heavy as steel and once poured it can be more difficult to lift and move.
What are the concrete specifications for a cattle guard form?
- 4,000 psi
- 5 to 6″ slump
- An 8×6′ form requires 1 1/3 cubic yards of concrete
- Fully cures in 28 days but will accept light traffic after 3 days
How much of a load will a finished cattle guard form support?
- According to engineer ratings an 8×6′ form pre-installed with 5/8″ GFRP will be rated at HS-20 or 32,000 lbs/axle.
- This assumes properly mixed 4,000 psi concrete having cured 28 days.
What about cattle guard form prices?
- Compared to most steel cattle guards, form prices are around 40% less including the concrete
- Farmers who have heavy equipment may benefit in installing pre-cast concrete cattle guards at even greater savings
The information provided above should hopefully offer fact based on my experience with cattle guard forms and how they compare to both steel and precast concrete cattle guards.