Concrete & Formwork
Concrete work involves heavy formwork, protruding rebar, pump trucks, chemical burns from wet concrete, and silica dust when it’s cut. Formwork collapses during pours have killed many workers.
- Construction
Top hazards
- Formwork and shoring collapse during or after pours
- Impalement on protruding rebar
- Concrete pump trucks: boom failure, hose whip, power line contact
- Cement burns: wet concrete is highly alkaline and causes deep chemical burns
- Silica dust when cutting, grinding or drilling cured concrete
- Falls from formwork and decks; struck-by from ready-mix trucks
Key practices
- Formwork and shoring designed, built and inspected per drawings; nobody removes shores until the engineer or competent person says the concrete is strong enough.
- Guard all protruding rebar against impalement. See Rebar Ironworkers.
- Stay out from under pump booms and away from the end of the discharge hose when it starts or clears.
- Wear waterproof gloves, tall rubber boots with pants tucked in, and eye protection. Wash wet concrete off skin right away.
- Cut and grind concrete using Table 1 silica controls. See Silica.
- Use a spotter for backing ready-mix trucks.
Formwork and shoring
- Formwork must hold the weight of wet concrete, workers, equipment and the force of the pour. It must be designed, built and maintained to do that.
- Drawings or plans for the formwork and shoring must be on site.
- A competent person inspects shoring before, during and after the pour. If shores settle, bend or move, stop the pour and get everyone clear.
- Reshoring follows the engineer’s plan. Forms and shores come out only when the concrete is strong enough.
Concrete pump trucks
- Outriggers fully extended on firm ground with pads
- Boom clear of power lines by a safe margin, with a spotter
- Hose end clear of people when pumping starts or after a blockage
- Nobody stands under the boom
- Clamps and pipeline sections inspected and secured
- Pump operator and hose handler agree on signals
Never try to clear a blockage by disconnecting a pipe under pressure. Concrete and air can blast out with deadly force.
Tilt-up and precast
Tilt-up panels and precast pieces weigh many tons and can fall during lifting, bracing or wind. Follow the erection plan, keep people out of the fall zone, brace panels before releasing the crane, and never remove braces without permission. See Lift Planning.
Cutting and drilling
Saw cutting, coring and grinding concrete release crystalline silica. Use water or vacuum dust collection on the tool, following OSHA’s Table 1, and wear the respirator it requires. See Core Drills and Cut-Off Saws.
Standards & references
- 29 CFR 1926 Subpart Q: Concrete and masonry construction (1926.700–.706)
- See also: Concrete Finishers
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