Stick-built erection

How does Stick-built erection work, step by step?

1. 1

   Step 1: Survey the route and the site before choosing the method

   The decision between modular and stick-built is made on evidence, not preference. The team surveys the delivery route from the port or the works to the site gate, checking road widths, bridge capacities, headroom, turning radii and any restrictions along the way, then assesses the site itself for laydown, assembly area and crane standing. Where large modules cannot be delivered, cannot be turned into the site or cannot be lifted from any available crane position, stick-building follows. That assessment is done early enough to be built into the contract.

2. 2

   Step 2: Agree the erection split with the plant supplier

   The plant supplier fabricates to suit the erection method, so the split between shop work and site work has to be fixed before fabrication starts. The parties agree what arrives as sub-assemblies, what arrives loose, how components are marked and packed, and in what sequence they are delivered. Delivery sequence is critical on a stick-built job because the site assembles in erection order and has nowhere to put components that arrive out of turn. A delivery schedule tied to the erection programme is agreed and then managed weekly.

3. 3

   Step 3: Plan the erection sequence and the temporary works

   Stick-building means partially complete structures standing for long periods, so temporary support, bracing and stability during erection are designed rather than assumed. The erection sequence is set out step by step, with the temporary works that each step depends on identified alongside it. Crane positions, radii and capacities are worked out for the heaviest individual component rather than for a module, which is usually what makes ordinary cranage sufficient.

4. 4

   Step 4: Establish site fabrication and welding facilities

   Because so much joining happens on site, the project sets up proper facilities for it: covered fabrication and preparation areas, consumable stores with controlled conditions, welder qualification and testing arrangements, heat treatment equipment and a non-destructive examination capability that can keep pace. Weld traceability is set up from the start, with every joint numbered, allocated to a welder and tracked through examination and acceptance. On a stick-built job this system is the backbone of the quality record.

5. 5

   Step 5: Erect the supporting structure and set the datum

   The structure goes up first and is surveyed, because everything that follows is positioned from it. On a stick-built unit the accumulation of small errors is a genuine risk: each component is set from the last, and a drift that would not matter once matters greatly by the fiftieth piece. Independent survey control is established outside the working area and every few stages of erection are checked back against it rather than against the previous piece.

6. 6

   Step 6: Assemble the unit piece by piece in erection sequence

   Components are lifted, positioned, temporarily supported, aligned and then joined. Alignment is checked before joining rather than after, and temporary supports stay in place until the permanent arrangement can carry the load. Work fronts multiply as the unit rises, so co-ordination between trades sharing the same access becomes the daily management task. Protection of completed work from adjacent activity - grinding, welding, painting - is planned rather than left to good intentions.

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   Step 7: Manage the workforce, access and supervision peak

   A stick-built job needs a much larger site workforce than a modular one, and it needs it for longer. Welfare, access, transport, training and supervision all have to be scaled for that peak, and the supervision ratio is the number that usually gets underestimated. Many work faces spread across a tall structure need supervisors and inspectors who can actually reach them, which in practice means designing the access to suit the inspection regime as well as the work.

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   Step 8: Inspect, clean and turn over as work completes

   Inspection keeps pace with erection rather than following it, because access closes behind the work. Weld records, alignment checks, support settings and cleanliness records are completed and signed off area by area as they are finished. Internal cleaning and steam blowing remain specialist operations executed by the plant supplier and the commissioning team under the operator's permit-to-work system. Completed systems are turned over to commissioning individually, which lets the commissioning team start while erection continues elsewhere.