Rebar detailing services, from placing drawings to the bending schedule.

The schedule is the order, so the schedule has to be right

Rebar detailing is the point where a design becomes a purchase. A bar bending schedule is not a document that describes the works; it is the instruction a cut-and-bend supplier prices, cuts and delivers against. A wrong shape code is not a drafting error, it is a load of steel on site that will not fit.

A package normally carries:

• Placing drawings — plans, sections and elevations showing every bar in position, with spacing, cover, mark numbers and laps.
• Bar bending schedules in the standard form your region uses, with shape codes, dimensions, lengths, quantities and weights.
• Mesh and fabric schedules, including cutting patterns and lap arrangements.
• Coupler, threaded bar and starter details, with the supplier's system called out where one is specified.
• Reinforcement models where the project is modelled, so congestion is resolved in three dimensions rather than argued about on site.
• Bar lists and weight summaries reconciled to the drawing, by pour, by element and by release.

The elements a reinforcement package covers

Reinforcement detailing is element work before it is drawing work. Each element type has its own failure mode, and the package is organised around that rather than around sheet numbers:

• Foundations — pad and strip footings, pile caps, rafts and ground beams, where starter bars and their projection lengths decide whether the next pour is possible.
• Columns and shear walls, including wall stacks and lift cores that reinforce continuously through many pours and have to lap in positions the formwork cycle allows.
• Beams and band beams, with curtailment, links and shear reinforcement set out so the cage can actually be tied and dropped.
• Slabs — suspended, flat plate, ribbed, transfer and slabs on grade — including mesh layouts, additional bars at openings and column heads, and trimmer bars nobody remembers to draw.
• Retaining and basement walls, where cover, crack control and construction-joint reinforcement are the design, not a detail.
• Stairs, landings and upstands, and reinforced concrete masonry with its bond beams, filled cores and dowels.
• Junction and coordination drawings at beam–column joints, wall–slab intersections and transfer zones, drawn at a scale the steelfixer can read.

Where a project needs a record of what was built rather than what was designed, as-built reinforcement drawings are produced against the same marks, so the record reconciles with the schedules that were ordered and placed.

Shape codes and schedules that match the bender

Every region schedules reinforcement differently, and the differences are enforced by machines, not by convention. We schedule to the standard the supply chain on your project actually works to:

• BS 8666 for the United Kingdom and markets that follow it — shape codes, bending dimensions, tolerances and the scheduling rules that go with them.
• ACI 315 detailing practice with the CRSI Manual of Standard Practice for North America, scheduled the way a domestic fabricator expects to receive it.
• AS/NZS 4671 material designations with AS 3600 and NZS 3101 detailing rules for Australia and New Zealand.
• EN 1992 with the relevant National Annex, and reinforcement drawn with the symbols of EN ISO 3766.

Where the supplier runs automated bending lines, schedules are issued as machine data as well as documents, so the shapes on the bender are the shapes on the drawing. Bending radii are checked against bar diameter and steel grade rather than assumed, because a radius that a mill-standard bar will not take is a schedule that comes back.

Numbering and file format follow the supply chain as well. Bar marks are allocated the way the site works — by pour, by element or by drawing — and stay stable through revisions, so a mark on a tag in the yard still means what it meant on the drawing that ordered it. Schedules leave as documents and as data: BVBS records for European bending lines, ASA-format bar lists where the North American fabricator's system expects them, and CSV or the client's own layout where the ordering system reads that instead.

How the work runs, pour by pour

Reinforcement is delivered against the concrete programme, not against a drawing list. At intake we agree the pour or release breakdown, the cover requirements, the lap and anchorage basis, the coupler systems, and which details are already fixed by the designer's typical sheets.

The AI-driven part of the work is the volume: modelling or drawing the bar arrangement, applying the typical details, generating marks, building the schedule, computing lengths and weights, and producing the sheets. Senior engineers spend their time on the parts that decide whether it can be built — congested nodes, transfer zones, pile caps, changes in section, and anywhere the designer's detail meets reality.

Issue is by release, under revision, with a schedule that always matches the drawing it was cut from. When a design change lands, the affected marks are identified and the delta is issued, so nobody re-orders a pour that has not changed.

Machine-checked, bar by bar

Automated checks run across the drawing and the schedule together before any human review. Reinforcement is the discipline where this pays most, because the errors are arithmetic and repetitive and a checker's attention is finite.

• every bar mark on a drawing exists in the schedule, and every scheduled mark appears on a drawing;
• shape code geometry is valid — leg lengths sum to the total length, hooks and bends are legal for the shape used;
• bending radii and bend allowances against bar diameter and grade;
• lap and anchorage lengths against the governing code, concrete grade and bar position;
• cover to every face, including the faces people forget, checked against the specification;
• quantities and weights reconciled between drawing, schedule and summary;
• mark uniqueness across the release, and revision consistency between sheet and register.

A senior engineer then reviews the package with the check results in front of them and signs it. What you receive is not just a schedule; it is a schedule someone was willing to put their name against.

Congestion, cover and constructability

Most reinforcement problems on site are not design problems. They are the moment two correctly designed bar groups meet in the same 200 millimetres, along with the cast-in items nobody drew.

Where a model exists, we resolve that before it reaches the slab: bar-to-bar clearance in beam-column joints and transfer structures, bar against post-tensioning ducts, bar against cast-in plates, sockets, conduit and drainage, and the physical question of whether the cage can be assembled and lowered in the order the site intends to build it. Where the answer is no, it comes back as a marked-up query with a proposal, not as a note saying the contractor should coordinate.

The same discipline applies to reinforcement in precast elements, where the constraint is the mould rather than the formwork, and to lapping arrangements that have to work with the pour sequence the site has already committed to.

Bar length, waste and what a schedule quietly costs

Reinforcement is bought by weight and cut from stock lengths, so the schedule decides the bill as much as the design does. A detailer who ignores that produces a correct schedule with an expensive offcut pile behind it.

The practical levers are ordinary and they add up: laps positioned so bars are cut from stock length rather than leaving a short remnant every time; bar lengths grouped so the fabricator's cutting optimiser has something to work with; couplers used where the lap length and the congestion they cause cost more than the coupler does; mesh sheets set out to reduce trimming; and bundle sizes and tagging arranged by pour and by gang so the right steel is on the right part of the slab on the right day.

None of that is worth doing at the expense of the design. Development and lap lengths, cover, and bar positions come from the code and the engineer, not from the cutting list. What is negotiable — where a lap falls within the permitted zone, which bar mark absorbs a rounding, whether a length is 11.8 metres or 12.4 — is where the saving lives, and it is decided while the schedule is being built rather than argued about after the steel arrives.

Codes, regions and the structures they govern

Detailing rules move with the code: ACI 318 in North America, EN 1992 with National Annexes across Europe, BS EN 1992 with BS 8666 scheduling in the United Kingdom, AS 3600 and NZS 3101 in Australia and New Zealand. Development lengths, minimum bend diameters, cover for exposure class and fire, and the permissible lapping arrangements all change, and so do the automated checks.

The work spans the structures where reinforcement is the programme: bridges and their piers, abutments and decks; tunnels and cut-and-cover boxes; water and wastewater structures where crack width and cover control the detailing; foundations and cores for tall buildings; and the heavily reinforced bases and plinths under industrial equipment.

One partner, one signature

BuildTwin produces the reinforcement package, checks it, and signs it. One delivery lead, one register, one programme, one company answerable for the quantities you order against — not a pool of people you have to manage.

We work inside your common data environment where you have one, follow your drawing and mark conventions rather than imposing ours, and hand over a register at the end that reconciles what was issued, when, and against which revision of the design. When the programme accelerates, the system produces more; the review and the signature stay with the same senior engineers.