Platform Link Bridges

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A bridge between platforms

2 spans of 30 m, each a tubular box truss 4 m wide and 4.5 m deep, meeting on a tripod. People, pipes and cables cross on it. Span, section and loads follow the client’s design.

Scroll to see how it is built · drag to turn it round

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4 chords

Each span has 4 tubular chords running its full length. We roll the cans from plate and weld them seam by seam.

How is it possible at Allmarc?

Three-roll pinch cum pyramid plate rollsRolls plate up to 40 mm

Used here for: 4 chords

• Rolls plate up to 40 mm

All our machinery

Submerged-arc (SAW) welding lineFull-penetration welds on built-up sections

Used here for: 4 chords

• Full-penetration welds on built-up sections

All our machinery

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Verticals and diagonals

Tube ends are profile-cut to the saddle shape of the chord, so each joint fits tight before welding starts.

How is it possible at Allmarc?

CNC profile laserTube, beam and structural profile cutting

Used here for: Verticals and diagonals

• Tube, beam and structural profile cutting

All our machinery

Manual MIG weldingQualified welders, including 6G

Used here for: Verticals and diagonals

• Qualified welders, including 6G

All our machinery

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Cross frames and plan bracing

Floor beams every 3 m, top cross members and plan bracing keep the box square during the lift and in a storm.

How is it possible at Allmarc?

Kotec newRun10DX CNC beam drilling lineH-beams up to 1,000 x 500 mm

Used here for: Cross frames and plan bracing

Heavy profiles that need precise holes, where plasma cannot do the job: the lower structure and panel borders of a ground flare, and every bolted PEB and multi-storey frame.

• H-beams up to 1,000 x 500 mm
• Drills 3 faces in one pass
• Channels, angles and box sections

All our machinery

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Walkway

A grated walkway 1.5 m wide with handrails and toe boards on both sides, and steps down to each deck.

How is it possible at Allmarc?

Grip-Strut walkway automation linePunching, embossing, edge bending, shearing

Used here for: Walkway

• Punching, embossing, edge bending, shearing
• Single-piece planks up to 8 m

All our machinery

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Pipes and cables

Pipe shoes sit on every floor beam and a cable tray hangs under the top frame. The pipes and cables are supplied by others.

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Fixed and sliding bearings

Each span is fixed at the platform end and slides on the tripod, so the platforms can move in the waves without loading the bridge.

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Padeyes

4 padeyes on the top chords of each span. A crane vessel lifts the span into place in one piece.

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Support tripod

A rolled column on 3 raking legs carries both spans where they meet. The platforms at each end are shown for context.

How is it possible at Allmarc?

Three-roll pinch cum pyramid plate rollsRolls plate up to 40 mm

Used here for: Support tripod

• Rolls plate up to 40 mm

All our machinery

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A kit of parts

Chords, bracing, walkway, bearings and tripod: every member numbered, match-marked and packed in erection sequence.