Slab Formwork Technical Glossary
An expert-grade glossary defining over 40 key industry terms, mechanics, and structural principles.
A comprehensive dictionary defining foundational concepts, abbreviations (e.g. WLL, PE, PSI), and material specifications used daily on concrete horizontal decks shoring works.
Admixture
Chemical compounds added to fresh concrete during mixing to modify its curing properties, such as water reducers, retarders, or accelerators.
Alloy 6061-T6
A structural magnesium-silicon aluminum alloy treated for peak tensile strength, featuring high bending fatigue resistance, ideal for formwork frames.
Anchor Bolt
A high-strength fastener cast in cured slabs or walls, used to anchor push-pull alignment braces and edge safety brackets.
ANSI A10.9
American National Standard safety guidelines governing temporary concrete shoring, placing, and stripping procedures on sites.
Axial Load
A pure compression force applied directly down the vertical center of a shoring prop or support column.
Birch Plywood
High-density multi-ply hardwood veneer sheets coated with phenolic resin, used as forming face for smooth class-A concrete finishes.
Bleeding
The migration of excess mix water toward the top surface of freshly poured concrete slabs due to structural gravity settling.
Blowout
A catastrophic structural failure where intense concrete pressure rupture forms or dislodges locking hardware, leaking wet slurry.
Bulkhead
A temporary barrier form installed orthogonal to the main deck, designed to cleanly terminate concrete joints between separate pour phases.
Camber
An intentional upward curvature designed into secondary aluminum beams to compensate for elastic deflection under heavy wet concrete weight.
Casting Bed
A flat structural concrete floor layer treated with release chemicals, used to cast perimeter concrete panels for tilt-up construction.
Chamfer Strip
A bevel shaped wood or plastic insert tacked into form joints, producing a smooth chamfered corner on the edge of cured concrete.
Class A Finish
An architectural concrete surface specification requiring extremely flat faces, with minimal joint lines or air pocket voids.
Cold Joint
An undesirable structural boundary layer formed when fresh concrete is poured against a previous batch that has already begun setting.
Composite Panel
Formwork sheet panels using high-density structured polyolefin composites instead of standard wood veneer, boosting cyclical re-uses.
Compressive Strength
The maximum compressive stress a cured concrete cylinder can carry without failure, measured in PSI or MPa.
Curing
The chemical hydration process that builds concrete strength, requiring controlled temperature and moisture levels over 28 days.
Deflection
The elastic downward sagging curve formed by formwork panels or secondary beams under temporary concrete gravity loads.
Drophead
An engineered quick-release device on top of shoring props that drops the main layout support frame by 60mm while keeping vertical shores loaded.
Dywidag Thread
A hot-rolled high-tensile steel tie bar featuring a robust continuous coarse thread pattern, designed to resist intense concrete tension pressures.
Early Stripping
The systematic removal of formwork panels 36 to 72 hours post-pour, leaving props loaded to support curing slabs.
Eccentric Load
A compression load applied off-center on a shoring prop, inducing bending moments that reduce its carrying capacity.
Elastic Limit
The maximum bending stress a structural steel or aluminum component can absorb without suffering permanent physical distortion.
EN 1065
The European structural safety standard regulating telescopic shoring prop load classes, threading designs, and pinch protection.
EN 13374
The European code regulating structural perimeter edge safety barrier systems and fall prevention platforms.
Flange Clamp
A mechanical wedge claw used to secure aluminum joist flanges to primary support beams without drilling.
Flatness Index (Ff)
An ASTM standardized measure of concrete floor flatness, tracking localized surface waviness along screeded paths.
Form Release Agent
A specialized chemical oil sprayed on panels before pouring, preventing concrete from bonding to the forming face during stripping.
Green Concrete
Freshly placed concrete that has set but has not yet developed full cured design compressive strength.
H20 Timber Beam
A standard structural wood support beam measuring 20cm deep, with spruce flanges and multi-ply web boards.
Hydrostatic Pressure
The deep outward pressure exerted by liquid concrete against form panels, scaling with slab thickness.
Levelness Index (Fl)
An ASTM metric evaluating overall horizontal levelness across a complete concrete slab deck floor.
Live Load
Temporary forces on formwork from labor crews, dynamic concrete pumps, motorized buggies, and tool placement.
Mudsill
A thick wood block placed under shoring prop baseplates to distribute vertical weight and prevent sinking into soil.
OSHA Subpart Q
US federal safety standard 29 CFR 1926 regulating concrete forming, shoring loads, layout design, and safety compliance.
Phenolic Film Overlay
A high-density polymer resin sheet bonded to plywood veneer faces under heat, producing a smooth surface and shielding from moisture.
Post-Tensioned (PT) Slab
A structural concrete deck containing internal high-strength steel cables tensioned after concrete reaches cured strength thresholds.
Primary Beam
The heavy support girder spanning directly across shoring heads, carrying secondary joist loads.
Reshoring
Installing secondary shoring props under stripped slabs to distribute gravity weight from active upper floor pours.
Safety Factor
The ratio of ultimate failure load to the rated working load limit; Slabform systems apply a minimum 2:1 safety factor.
Secondary Beam
The joists running directly under formwork panels, transferring loads to primary girders.
Shoring Prop
A certified vertical telescopic column to support green concrete decks, available in steel or aluminum.
Slab Thickness
The depth of the structural concrete deck floor, dictating overall weight and shoring grid density.
Stripping
The systematic dismantling and removal of temporary formwork panels and secondary beams after concrete cures to target strength.
Tie Rod
A high-tensile steel rod passed through vertical wall forms to resist outward pressure.
Tilt-Up Construction
A building method where concrete wall panels are cast flat on the floor slab and tilted vertically with a mobile crane.
Toolbox Talk
A short, on-site safety meeting focused on specific procedures, like drophead wedges or prop placement.
Working Load Limit (WLL)
The maximum safe structural load rating a component can carry in daily site operations.
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