Structural metalwork refers to all fabricated steel and metallic components forming part of a civil engineering project. This includes primary structural elements (beams, columns, trusses), secondary components (bracing, purlins, handrails), and metal accessories (fixings, bolts, bearings, gratings, etc.).
1. Scope of Class M
- Covers all structural steelworks and other metals required in civil engineering projects.
- Includes fabrication, delivery, erection, fixing, welding, bolting, painting, and protective treatment.
- Typical works measured under this class include:
- Bridges, gantries, towers, frames.
- Roof trusses, girders, portal frames.
- Walkways, platforms, gratings, handrails, ladders.
- Metal bearings and expansion joints.
- Anchorage, supports, and embedded steelworks.
2. Units of Measurement
- kg (weight of fabricated steelwork).
- m² (for surface treatments like painting or galvanizing).
- No. (for bolts, bearings, or special items).
- m (for linear items such as railings, ladders, or pipes).
3. Method of Measurement (per CESMM4 rules)
- Steelwork is measured by weight, unless otherwise specified.
- The net weight of finished steel sections is taken (without allowance for rolling margins).
- Bolts, rivets, and welds are included with the members unless separately specified.
- Protective coatings (painting, galvanizing, fireproofing) are measured separately in m² of surface area.
- Fixing and erection are deemed included in the item description.
4. Itemization & Description Rules
CESMM4 requires that items in Class M must describe:
- Type of structural element (beam, column, truss, bracing).
- Material grade (mild steel, high tensile steel, aluminum).
- Fabrication details (welded, bolted, riveted).
- Location and function (bridge deck girder, tower support).
- Surface treatment (shop primed, galvanized, painted).
5. Typical Items under Class M
(a) Primary Structural Members
- Rolled steel beams, channels, angles, tees.
- Fabricated plate girders, box sections, trusses.
- Bridge members (deck beams, stringers, cross girders).
- Measured in kg of finished steel.
(b) Secondary Steelwork
- Bracing, stiffeners, cleats, splice plates.
- Purlins, side rails, small fabricated supports.
- Gratings, flooring, checker plates, catwalks.
- Measured in kg.
(c) Ancillary Metal Items
- Ladders, handrails, balustrades, fencing.
- Bearing plates, shoes, gussets.
- Hinges, rollers, expansion joints.
- Measured in m, m², or No. depending on nature.
(d) Fastenings & Connections
- High-strength friction grip bolts, ordinary bolts.
- Rivets, pins, washers, nuts.
- Welds – deemed included unless separate testing specified.
(e) Surface Treatments
- Shop primer, galvanizing, epoxy coating, fireproofing.
- Measured in m² of surface area treated.
6. Example Measurement Items (CESMM4 Style)
- Steel Beams:
- 20,000 kg of Grade S355 fabricated and erected universal beams for bridge deck.
- Ladders & Handrails:
- 40 m of galvanized mild steel tubular handrails, including bends and joints.
- Grating Walkways:
- 120 m² of galvanized open steel gratings, fixed in position.
- Bearings:
- 8 no. elastomeric bearings with steel plates, installed and grouted.
- Painting:
- 3,000 m² of structural steel surface painted with 3-coat epoxy system.
7. Site Examples of Structural Metalwork
- Highway Bridge: Steel plate girders, bearings, handrails, expansion joints.
- Industrial Plant: Pipe racks, platforms, staircases, gratings, steel towers.
- Hydraulic Structure: Steel gates, stoplogs, embedded frames, lifting beams.
- Airport/Metro Works: Canopies, terminal roof trusses, escalator steel supports.
✅ Summary:
Class M (Structural Metalwork) in CESMM4 ensures structural steel and other fabricated metals are measured consistently by weight or surface, with ancillary works measured separately. Descriptions must include material, fabrication, and treatment details, while erection and fixing are deemed included in the item unless stated otherwise.
