HLY-OP-04: Hydraulic Collapsible Box Culvert Mold Stripping & Clamping SOP

1. Pre-Pour Setup & Mechanical Wedging

Spray bio-based release oil over inner core and outer formwork panels.

Start hydraulic station (set to 18 MPa); shift lever to "Expand"; drive 4-corner diagonal wedge linkages until walls seat against stops.

Verify corner rubber seals are flush; engage mechanical wedge safety pins; shut down hydraulic pump.

Close outer panels; install and torque high-strength tie-rods to 280 N·m.

Pour SCC concrete symmetrically in lifts to maintain balanced hydrostatic pressure on the core.

Apply thermal curing blankets over top face until green strength reaches stripping threshold.

Remove all outer tie-rods; release base hinge clamps; swing outer formwork panels outward by 150 mm.

Disengage mechanical safety pins; start hydraulic station and switch valve to "Retract".

The 4 synchronized cylinders pull corner wedges, collapsing all four inner faceplates inward by 25–30 mm.

Visually verify 100% clearance separation; rig overhead crane to core lifting lugs; lift vertically.