Fabrication Phase Requirements

This phase transforms the design into ready-to-erect components.

Quality Control (QC) in the Shop:

Cutting and Drilling: Must be precise according to shop drawings. Holes for bolts must be accurately aligned.

Fit-Up: Members must be trial-fitted before welding to ensure proper alignment and gaps.

Welding: Must be performed by certified welders following Qualified Welding Procedures (QWPs). Welds must be visually inspected and often tested by Non-Destructive Testing (NDT) like ultrasonic (UT) or magnetic particle (MT) testing.

Tolerances: Fabrication must adhere to strict dimensional tolerances specified by AISC.

Surface Preparation and Coating:

Surface Preparation: Steel must be cleaned of mill scale, rust, and contaminants. This is often done by abrasive blasting (e.g., to a Sa 2.5 cleanliness standard).

Priming/Painting: Application of a primer coat to protect against corrosion during transport and storage. The type and thickness of the paint system must meet the design specification.

Identification and Shipping:

Each piece must be clearly marked with an erection mark that corresponds to the erection drawings for easy identification on site.

III. Erection (On-Site Construction) Phase Requirements

This is the high-risk phase where safety and precision are paramount.

Site Preparation and Foundation:

Foundation Verification: Before steel erection begins, the foundation (anchor bolts, grout, and concrete strength) must be surveyed to ensure it is within the specified tolerances for location, elevation, and planarity.

Lifting and Rigging:

Crane Selection: Cranes must have adequate capacity and reach for the heaviest and farthest lifts.

Lift Plans: A detailed plan for each major lift, prepared by a competent person, addressing crane setup, rigging, and personnel roles.

Rigging Gear: All slings, shackles, and hooks must be certified and inspected before use.

Safety Requirements:

Fall Protection: This is the number one priority. 100% fall protection is required for workers at heights over 6 feet. This includes guardrails, safety nets, or personal fall arrest systems (PFAS).

Site Security: The erection area must be barricaded to prevent unauthorized access.

Competent Personnel: The steel erector must be experienced, and a designated competent person and qualified person must be on site to oversee safety and technical aspects.

Erection Sequence and Temporary Bracing:

Sequence: Steel must be erected in a sequence that ensures stability at all times. The Erection Drawings will specify this sequence.

Temporary Bracing: Columns and beams must be stabilized with temporary guying or bracing as they are erected. The structure is not stable until all permanent bracing and decking are installed.

Bolting and Welding:

Bolting:

Installation: Bolts must be installed correctly (snug-tight, pretensioned, or slip-critical) as per the design.

Verification: Use calibrated torque wrenches or tension calibrators to verify the required bolt tension.

Field Welding:

Must be protected from the weather (wind, rain).

Performed by certified welders using qualified procedures.

Requires inspection and NDT as specified.

Tolerances:

Erection must comply with permitted tolerances for plumb (vertical alignment), elevation, and camber (intentional curvature in beams) as defined in codes like the AISC Code of Standard Practice.

IV. Post-Erection & Completion Requirements

Inspection:

A series of inspections are conducted by the erector's QC, the general contractor, and ultimately the building inspector to verify compliance with the approved plans and codes.

Fireproofing:

Bare steel loses strength rapidly in a fire. Most buildings require a fireproofing material (e.g., spray-applied fire-resistive material (SFRM), intumescent paint, or board insulation) to be applied to the structural members to meet the fire-resistance rating specified by code.

Final Documentation:

The contractor typically provides a package of final documents, including:

As-built drawings.

Material certifications (MTCs).

Welding and bolting inspection reports.

Manufacturer's data for fireproofing and paint.

Summary of Key Parties' Responsibilities

Structural Engineer: Design the safe and efficient structure.

Fabricator: Accurately manufacture components to the design.

Steel Erector: Safely and precisely assemble the structure on site.

General Contractor: Coordinate the site, provide foundations, and manage overall safety.

Building Inspector: Verify compliance with the approved plans and building codes.

Adherence to these requirements ensures that a steel structure will perform as intended throughout its design life.