• info@mepco.co
  • Saudi Arabia – Riyadh – Al Sahafah District
  • Sat- Thurs (9 am - 6 pm)

Steel Structure Shop Drawings: Review and Approval Guide Before Fabrication

Transforming structural designs into actual production instructions is one of the most critical stages in steel structure and industrial building projects. Once steel has been formed, cut, drilled, and welded in the factory, making simple modifications on-site is no longer practical.

Discovering a discrepancy of only a few millimetres in anchor bolt holes—or an incorrect angle where a beam plate meets a concrete support—during lifting and erection can bring site operations to an immediate standstill. It may leave heavy cranes idle, lead to costly refabrication, and introduce structural risks if unauthorised field modifications or hole enlargement are used as temporary remedies.

The fundamental engineering solution lies in the rigorous review and comprehensive approval of steel structure shop drawings before cutting and welding equipment is authorised to begin production. The greater the accuracy of the steel structure shop drawings, the lower the risk of coordination conflicts, refabrication, and erection delays.

Prepared for consulting engineers, structural designers, and steel contractors in Saudi Arabia, this guide explains the critical documents and technical requirements that must be reviewed and approved to achieve fabrication in accordance with leading structural and regulatory standards.

Direct Answer

Approving steel structure shop drawings requires a coordinated comparison between contractual design drawings and detailed shop and erection drawings. The review must verify steel grades and thicknesses, confirm that moment and shear connections can withstand the specified wind and seismic forces, check anchor bolt coordinates and elevations, approve welding symbols in accordance with AWS D1.1, and confirm compliance with hot-dip galvanizing and fire-resistant coating requirements under the Saudi Building Code before fabrication begins.

Executive Summary for Consulting Engineers and Project Managers

  • A rigorous pre-fabrication review can prevent more than 90% of site assembly problems caused by dimensional conflicts or insufficient bolt clearances.
  • Approval of steel structure shop drawings requires verification of Material Test Certificates and confirmation that the specified steel grades comply with SBC 306.
  • The Anchor Bolt Setting Plan is the principal coordination document connecting the civil contractor with the structural steel fabricator.
  • The review process is not complete until structural steel, HVAC, electrical, plumbing, and fire-protection systems have been jointly coordinated.

1. Why Are Design Drawings Not Sufficient for Fabrication?

Some non-specialist project managers assume that the approval of contractual design drawings authorises the factory to begin steel fabrication. This assumption represents a serious engineering risk.

Design drawings prepared by the structural engineer generally indicate grid lines, principal structural member sections, such as columns and beams, and maximum design forces, including moments, shear forces, and axial loads. They do not provide the detailed mechanical information required to manufacture every individual component.

This is the purpose of steel structure shop drawings, also known as shop or fabrication drawings. The steel detailer divides the building into thousands of separate components and plates, assigns each item a unique mark number, and specifies its exact dimensions, hole locations, cutting and bevel angles, and weld types and sizes.

If the consultant does not review the steel structure shop drawings against the original structural design philosophy, an incorrect assumption made by the fabricator may become a defective component that is difficult to erect or potentially compromises the building’s stability.

2. Engineering Review and Approval Matrix

A systematic review matrix should be used when checking steel structure shop drawings to ensure that no element affecting fabrication accuracy or erection safety is overlooked.

Review Item Engineering Verification Requirements Applicable Reference Approval Requirement
Steel grades and material specifications Verify that section and plate grades, such as ASTM A36 or S355JR, match the approved specifications SBC 306 and SASO specifications Mechanical and chemical properties must match the Material Test Certificates
Anchor Bolt Plan Verify bolt grids, diameters, embedment lengths, and projections above concrete Concrete foundation drawings and ACI requirements Coordinates must match the field survey, with temporary setting templates provided
Moment and shear connection design Review connection plate thicknesses and high-strength bolt diameters AISC 360 Detailed calculations must demonstrate adequate connection capacity
Welding symbols and details Review weld type, effective throat thickness, and welding-consumable classification AWS D1.1 Details must comply with the fabricator’s approved WPS
Galvanizing and treatment openings Verify vent and drain holes in hollow sections ASTM A123 and ISO 1461 Openings must be structurally safe and positioned without compromising appearance
Assembly and erection drawings Review erection sequence and temporary bracing locations and types Construction management and occupational safety requirements Part marks must be clear, with sufficient space for tightening and erection equipment

3. Reviewing Structural Connections

Connections require particular attention during the review of steel structure shop drawings because many steel structure failures originate at connection points rather than through the fracture of primary members.

The engineering review should cover the following:

  • Moment connections: Verify end-plate thicknesses, column stiffeners required to prevent flange buckling, and the use of approved pre-tensioned high-strength bolts, such as Grades 8.8 and 10.9 or ASTM A325/A490.
  • Simple shear connections: Confirm that angles or shear plates permit the expected end rotation of the beams and do not generate unintended bending moments that transfer into the columns.
  • Tool clearances: Review the space around bolt heads and nuts to ensure that site technicians can position calibrated torque wrenches and tighten the bolts without interference from beam flanges or adjacent stiffener plates.

4. Anchor Bolt Interface with Civil Works

The Anchor Bolt Plan is the principal interface document between the civil and concrete contractor and the structural steel fabricator. For this reason, steel structure shop drawings must contain all details required to prevent conflicts between completed foundations and column base plates.

Steel columns should not be cut or assembled before completing the following checks:

  1. Verification of actual grids and elevations: Review the as-built survey of the concrete foundations and compare the anchor bolt grid dimensions with the shop drawings. The results must remain within applicable code tolerances, commonly ranging from ±3 mm to ±5 mm depending on the approved details.
  2. Base-plate hole dimensions: Use oversized holes only within the limits permitted by AISC and SBC 306 to accommodate minor surveying deviations. Heavy plate washers of sufficient thickness must cover the openings and ensure safe load transfer.
  3. Grouting allowance: Provide an appropriate vertical gap, typically between 25 mm and 50 mm, beneath the base plate to accommodate non-shrink grout. Double levelling-nut arrangements should also be reviewed.

5. Surface Protection and Saudi Building Code Compliance

Saudi Arabia’s environmental conditions make surface-treatment requirements an essential part of fabrication detailing. Therefore, steel structure shop drawings must clearly define corrosion-protection and fireproofing requirements before production begins.

The review should cover:

  • Hot-dip galvanizing openings: For hollow structural sections and pipes, including HSS and CHS members, the drawings must identify the locations and diameters of all air vents and molten-zinc drainage holes. These openings prevent dangerous internal pressure, reduce the risk of distortion or rupture, and allow zinc to reach internal surfaces.
  • Fire-resistant coatings: Saudi Civil Defense requirements and SBC 801 must be reviewed to ensure that connections and bolts can accommodate the specified intumescent coating thickness. Details should not obstruct spray access or dry-film thickness inspection.
  • Uncoated areas in slip-critical connections: Contact surfaces in slip-critical connections must be clearly identified as unpainted unless a qualified coating capable of achieving the required design slip coefficient is specified.

6. Coordination with MEP Systems

The engineering value of approved steel structure shop drawings is fully realised only when the review covers potential clashes between the steel frame and HVAC, electrical, plumbing, and fire-protection systems.

Beam Penetrations

Commercial and industrial buildings may require ductwork or main fire-protection pipes to pass through steel beams to preserve the required clear height.

The drawings must identify the position and size of every opening and provide the required reinforcement details approved by the structural consultant. No thermal cutting or unapproved field opening should be permitted after the steel member leaves the factory.

Suspended Services and Mechanical Equipment Loads

Cable tray supports, ductwork, pipework, and overhead cranes must be reviewed. Secondary connection plates and support brackets should be incorporated into the fabrication drawings.

This prevents uncontrolled field welding on primary load-bearing members and reduces the risk of unintended stresses or deformations.

7. Metal Fabrication and Engineering Quality Control with MEPCO

Major industrial and engineering projects require a fabricator with the technical and digital capabilities needed to transform structural designs into fully coordinated fabrication models.

Through MEPCO Metal Industries, MEPCO uses advanced three-dimensional modelling and BIM technologies to produce and review steel structure shop drawings with the accuracy required by laser-cutting lines and CNC forming equipment.

These capabilities are integrated with MEPCO’s General Contracting services, providing owners and consultants with unified coordination between structural steel drawings, MEP service routes, and foundation works.

This integrated approach supports the early verification of anchor bolts, connections, and protective treatments. It also reduces disputes and variation orders while accelerating the fabrication, delivery, and erection of steel structures throughout Saudi Arabia.

8. Pre-Fabrication Drawing Approval Checklist

Before issuing Code A approval for steel structure shop drawings, the consultant should confirm that the following requirements have been met:

  • Have all steel section sizes, thicknesses, and material grades been checked against the approved design drawings and specifications?
  • Have calculation reports reports for all moment and shear connections been submitted and reviewed?
  • Has the Anchor Bolt Plan been compared with the as-built survey of the completed foundations?
  • Have all weld symbols, sizes, and types been specified in accordance with AWS D1.1 and the approved WPS?
  • Have the required vent and drain holes for hot-dip galvanizing been shown on all hollow sections?
  • Have epoxy and intumescent fireproofing systems and application areas been clearly specified?
  • Have all spatial conflicts between beams, trusses, and approved MEP systems been resolved?
  • Are the part marks clearly shown on all assembly and erection drawings?

9. Conclusion and Call to Action

Investing in the review and verification of steel structure shop drawings is an essential engineering safeguard for completing a project within its approved budget and programme.

Early and accurate approval transforms fabrication into a fast, controlled, and high-quality process. It reduces disputes and field modifications and supports the long-term safety and durability of steel structures in accordance with applicable Saudi codes and regulations.

If you are preparing steel structure shop drawings or planning the fabrication of a steel building or industrial structure, contact the engineering team at MEPCO Metal Industries to discuss your project and obtain specialist engineering support for accurate and efficient execution.

Frequently Asked Questions About Steel Structure Shop Drawings

1. What is the difference between shop drawings and erection drawings?

Shop drawings focus on each individual component and provide factory personnel and machinery with the cutting dimensions, holes, and welding details required for every plate, beam, or column.

Erection drawings provide the overall site assembly information required to install and connect the numbered components to one another and to the concrete foundations.

2. What are the risks of thermally enlarging bolt holes on-site without consultant approval?

Using gas flames or thermal cutting to enlarge bolt holes without formal engineering approval may alter the steel’s microstructure and affect its resistance to shear and tension. It can also compromise proper bolt contact and connection behaviour.

Such modifications may invalidate the fabricator’s warranties and expose the connection to failure under live, wind, or seismic loads.

3. How does SBC 306 affect the approval of welding details?

SBC 306 requires structural welding to comply with AWS D1.1. Welding Procedure Specifications and Procedure Qualification Records must be submitted, together with valid welder qualifications.

The required extent of non-destructive testing must also be identified for critical connections, including ultrasonic and magnetic-particle testing where applicable.

4. When must vent holes be included in drawings for hollow steel sections?

Vent and drain holes are mandatory when sealed hollow sections are to be hot-dip galvanized.

They prevent trapped air from expanding under the temperature of the molten zinc bath and allow zinc to enter and drain from the section, protecting internal surfaces against corrosion.

5. Who is legally and technically responsible for errors in steel structure shop drawings?

The steel contractor, fabricator, and appointed steel detailer remain directly responsible for dimensional accuracy, part identification, and fabrication details.

Send your request now