Discover the unique challenges of designing and detailing structural steel for major infrastructure projects like tunnels, bridges, and industrial facilities.

Structural steel plays a crucial role in modern infrastructure. It supports everything from roads and tunnels to railways and industrial facilities. Its combination of strength and flexibility makes it ideal for large-scale projects. However, working with steel at this level brings unique challenges that go beyond standard design and detailing.

In this blog, we’ll dive into these challenges in more detail. We’ll also share how Hadeed Engineering approaches these situations in real-world projects, turning potential roadblocks into solutions — backed by structural engineering experts who specialise in complex infrastructure projects.

1. Design Complexity in Structural Steel Infrastructure

Designing structural steel for infrastructure projects is often more complex than for typical building construction. Unlike standard buildings with uniform shapes and predictable loads, infrastructure must handle irregular geometries, changing site conditions, and strict long-term performance requirements.

A) Advanced Loading Conditions

Infrastructure elements such as bridges, tunnels, and elevated transport corridors are subjected to complex load cases. These include:

• Traffic-induced vibration and dynamic loads
• Wind pressure and aerodynamic effects
• Thermal expansion and contraction
• Equipment-induced forces in industrial facilities
• Seismic activity in high-risk zones

These forces often combine in ways that can’t be reliably captured using conventional hand calculations or simplified models.

B) Geometry and Structural Irregularity

Modern infrastructure often features skewed supports, curved spans, varying deck elevations, and asymmetric load paths. These factors lead to complex structural behaviors, particularly at connections and transition zones.

For example, skewed or curved steel bridges respond differently to live loads compared to straight bridges. This difference requires advanced modeling techniques to accurately predict deflection and moment distribution.

C) The Role of Finite Element Analysis (FEA)

Advanced modeling such as FEA helps engineers simulate how structures respond to a combination of load cases over time and under different environmental conditions. It is particularly useful for:

• Validating behaviour at non-standard supports
• Optimizing member sizing under mixed loads
• Stress analysis of complex welded or bolted connections

2. Detailing & Coordination Challenges

A) Precision at Large Scale

Steel detailing for infrastructure projects must address the scale and precision of massive structural components. Even small errors in shop drawings can result in expensive site modifications or unusable fabricated parts.

Every bolt hole, weld preparation, and plate thickness must be precisely specified and aligned with surrounding systems. Incomplete or overly general detailing creates uncertainty, often leaving contractors to interpret designs on-site — a risk that can compromise both cost and quality.

B) Coordination Across Disciplines

Infrastructure steel must integrate seamlessly with concrete elements, road and rail alignments, service penetrations, architectural features, and temporary works. Misalignment between disciplines — particularly structural, MEP, and civil — is one of the leading causes of rework and project delays.

These issues are amplified when design information is scattered across multiple platforms without a single, reliable source of truth. Effective steel detailing, therefore, must be both precise and fully coordinated across all disciplines.

C) Time Pressure and Documentation Quality

Fast-track infrastructure projects often require detailing teams to work alongside ongoing design and procurement activities. This approach increases the risk of version control errors or hurried outputs that may lack proper constructability review. In this phase, steel detailing becomes a critical function, directly influencing whether fabrication and construction can proceed efficiently and without delays.

3. BIM Implementation in Infrastructure Projects

Building Information Modeling (BIM) has become a key tool in the delivery of major infrastructure projects. It enables:

• Clash detection between structural, civil, and MEP systems
• Coordination of sequencing and installation access
• Early resolution of spatial conflicts before fabrication

When used effectively, BIM reduces rework, improves site efficiency, and allows for smoother integration of complex assemblies.

Barriers to Effective BIM Use

Despite its benefits, many teams face difficulties with BIM adoption. Challenges include:

• Inconsistent skill levels across parties
• Lack of standardized practices
• Software compatibility issues
• Resistance to changing established workflows

These issues slow down coordination, especially when subcontractors or consultants rely on traditional 2D documentation or are unfamiliar with newer models.

4. Fabrication & Construction Risks

A) Material Volatility and Supply Chain Disruptions

Global supply chains can be unpredictable for steel and related products. Price volatility, shipping delays, and inconsistent availability of specific grades affect procurement and fabrication schedules. This unpredictability can force substitutions or disrupt the installation flow.

B) Fabrication Quality and Workshop Coordination

Infrastructure steel is often fabricated across multiple locations to meet volume and timeline demands. Maintaining consistent quality across shops requires clear documentation and robust quality control processes. Fabrication errors are magnified on large infrastructure projects; a single out-of-tolerance element can halt progress across an entire span or section.

C) On-Site Constraints and Installation Complexity

Limited access, live traffic, constrained laydown areas, and staged handovers increase the difficulty of installing large, heavy steel components. Mistakes in sequencing, lifting plans, or connection tolerances can create significant safety risks and program delays.

Success on-site depends heavily on early planning, clear documentation, and practical constructability reviews, all of which must happen during the design and detailing stages, not after steel arrives on-site.

5. Durability & Lifecycle Challenges

A) Corrosion from Environmental Exposure

Bridges, tunnels, and coastal infrastructure are often exposed to high levels of moisture, salt, and airborne pollutants that accelerate corrosion. Without proper protection, steel structures can deteriorate quickly and lead to costly repairs or compromised safety.

Effective corrosion resistance requires:

• Careful specification of materials and finishes
• Proper drainage and water shedding detailing
• Access for inspection and maintenance

B) Fire Protection in Structural Steel

Steel can lose strength rapidly when exposed to high temperatures, which compromises the load-bearing capacity in the event of a fire. Infrastructure projects must meet strict fire resistance standards. These standards require passive fire protection systems like intumescent coatings or encasements.

Integrating fire protection into steel design has its own challenges:

• Allowances must be made for thicknesses of fireproofing systems.
• Connections and brackets must not obstruct coverage.
• Conflicts can arise with other building systems at compartment boundaries.

If these considerations are not factored in during detailing, remedial work may be needed post-installation, adding cost and complexity.

6. Project Delivery Complexity

A) Multiple Stakeholders with Competing Priorities

Infrastructure projects involve a diverse range of stakeholders with varying priorities. Maintaining alignment between them and responding to scope change without derailing the project are constant challenges.

B) Compressed Timelines and Sequencing Pressure

With staged handovers, road closures, and funding deadlines, infrastructure schedules leave little room for error. Steel must be fabricated, delivered, and erected in precisely the correct sequence, often within narrow site access windows. Any disruption in the steel package can impact multiple other workstreams.

C) Adopting New Tools and Standards

While advanced tools like BIM and digital twins improve coordination, they also introduce learning curves, interoperability issues, and new documentation standards.

How Hadeed Engineering Tackles These Challenges

1. Responding to Design Complexity

Our engineers apply Finite Element Analysis (FEA) and advanced modeling to assess the performance of structural steel under various types of loads. These tools support design decisions on projects with irregular geometry or mixed loading conditions.

In the Melton Station level crossing removal, steel framing for the elevated platform required careful modelling of load paths and restraint systems that interacted with precast and concrete structures. FEA and design coordination were used to meet safety and constructability requirements.

2. Delivering Accurate, Buildable Detail

In the Coolstore Road level crossing removal, our engineers created shop drawings for restraint blocks, struts, and bearing plates that required precise coordination with civil and concrete works. This accuracy supported field installation with minimal rework.

During the Lithocraft canopy extension, Hadeed Engineering resolved detailing discrepancies before the fabrication began. This supported the project with error-free drawings and timely steel delivery of the 24-tonne structure.

3. Using BIM to Coordinate Disciplines

Hadeed Engineering adopts BIM to align structural steel with civil, service, and architectural models. This approach enables clash detection, clear communication, and better sequencing.

On the West Gate Tunnel Project, our team modelled gantry stairs and barrier rails along an elevated roadway that intersected with complex civil and service systems. This coordinated 3D modelling supported smoother integration across construction stages.

4. Supporting Delivery Under Real Constraints

Industrial coordination is highlighted in the Titan Cement Coal Mill project. Hadeed Engineering detailed steel structures that interface with coal handling equipment, all within tight access constraints and compliance frameworks typical of heavy industry environments.

Across all projects, Hadeed Engineering’s outputs are designed with constructability in mind. Shop drawings reflect field tolerances and material specs to help fabricators and site teams stay on schedule and aligned with broader delivery milestones.

Planning a steel infrastructure project?

Keep your projects on track by partnering with Hadeed Engineering, your reliable engineering consultant in Australia, for expert structural solutions.