Slip Forming Operations

Slip forming is a continuous concrete construction method where the formwork rises as concrete is poured.
It is used for tower structures, silos, bridge piers, and core walls requiring rapid vertical construction.
The operation runs 24 hours a day without stopping until the full height is reached.
Workers stand on the rising platform which moves upward at approximately 200–300mm per hour.
Fall protection at the platform edge is critical as the structure rises to significant heights.
Concrete supply must be continuous — any interruption risks the formwork bonding to the hardening concrete.
Rebar fixing, insert placement, and finishing all happen simultaneously on the moving platform.
Fatigue management is essential due to the continuous 24-hour operation requiring shift rotations.
The hydraulic jacking system that raises the formwork must be monitored for level and alignment.
Access between the ground and the rising platform changes constantly as the structure grows.

Fall hazard	Workers on a continuously rising platform at increasing height face severe fall risks at every stage.
Continuous operation	24-hour non-stop operations create extreme fatigue risk that impairs judgement and reaction times.
Structural integrity	Interruptions, poor concrete, or misaligned formwork cause structural defects in the continuous pour.

Do

Don't

Install guardrails and toeboards at all edges of the slip form platform
Wear a harness when working at unprotected edges or during access transitions
Rotate shift teams to manage fatigue during the continuous 24-hour operation
Monitor the hydraulic jacking system for level, rate, and alignment continuously
Maintain a continuous concrete supply — coordinate with the batching plant in advance
Brief each shift on the current height, sequence, and hazards before they start
Provide safe access between the ground and the platform using enclosed stairways or lifts
Keep the platform clean and free from concrete build-up that creates slip hazards
Ensure adequate lighting on the platform for night working shifts
Record all pour data including jacking rates, concrete volumes, and shift personnel

DON'T work at the platform edge without guardrails or fall arrest equipment
DON'T allow workers to exceed safe shift durations during the continuous operation
DON'T interrupt the concrete supply without engineer assessment of the consequences
DON'T climb the outside of the rising structure to access the platform
DON'T ignore misalignment or uneven jacking — it affects the structural geometry
DON'T throw tools or materials from the platform to the ground below
DON'T continue the pour if concrete quality or workability is not within specification
DON'T allow debris to accumulate on the platform creating trip and slip hazards
DON'T skip the shift briefing — conditions change continuously as the structure rises
DON'T leave the jacking system unmonitored at any point during the operation

See also: Concrete Pour Safety | Formwork Erection and Striking

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