When it comes to industrial lifting operations, it’s easy to focus on the visible machinery — the crane bridge, hoist, or lifting tackle.
But behind the scenes, the unsung hero is the supporting structure that takes every load, shock, and cycle of movement. This is where EN 1993-6 plays a vital role.
EN 1993-6 is part of the broader Eurocode 3 framework for steel structures. It sets out rigorous, consistent rules for designing crane supporting structures — from overhead runway beams and gantries to the brackets, rails, and connections that hold everything in place.
Crane runways are far more demanding than many standard building structures. They must carry concentrated wheel loads, lateral and longitudinal forces from acceleration and braking, and dynamic impacts when loads are lifted or moved abruptly. Over time, these repeated stress cycles can lead to fatigue damage if not properly accounted for in the design. EN 1993-6 provides designers with the clear calculations, safety factors, and serviceability criteria needed to make sure these structures remain safe and efficient throughout decades of use.
What is EN 1993-6?
Formally titled Eurocode 3: Design of Steel Structures — Part 6: Crane Supporting Structures, this standard extends the general design rules in EN 1993-1 to deal with the specific demands posed by crane operations.
At its core, EN 1993-6 sets out how to calculate the various actions and load combinations that affect crane supporting frameworks. For example, the fundamental vertical wheel load on a crane runway beam is given by:
where:
is the self-weight of the crane,
is the lifted load,
is the number of wheels carrying the load.
However, static loads alone don’t paint the full picture. The sudden starting and stopping of the hoist, or impact when a load is lifted or set down, introduce dynamic effects. These must be included by applying a dynamic amplification factor:
where 
By providing these methods, EN 1993-6 helps engineers produce more realistic loading models that reflect how cranes really operate — not just how they look on paper.
Why Does It Matter?
The consequences of ignoring the guidance in EN 1993-6 can be severe. Supporting beams that aren’t designed for dynamic effects or lateral forces can develop excessive deflection, wheel misalignment, or even fatigue cracks in welds and connections.
A typical example is the horizontal forces created when a crane brakes or changes direction. These forces act along the runway beam’s axis and must be included:
where 
Skewing of the crane or crab can cause transverse horizontal forces too:
with 
Without considering these, wheels may exert uneven loads on the rails, wearing them out prematurely or causing derailment.
Moreover, the standard gives clear guidance on checking the ultimate limit states (ULS). For instance, the maximum bending moment at mid-span due to wheel loads is:
where 
Shear force at supports is:
These checks ensure that the runway beam has sufficient strength and stability under worst-case scenarios.
Key Design Considerations
One of the standout aspects of EN 1993-6 is its focus on fatigue. Unlike many building structures, crane runways face constant cyclic loading.
Welded details and bolted joints need to withstand millions of stress cycles without failure. The stress range for a typical welded connection is:
where 
The cumulative fatigue damage must be kept within safe limits using Miner’s Rule:
where:
= actual number of cycles at stress range i,
= allowable cycles for that stress range.
Beyond fatigue, EN 1993-6 deals with lateral-torsional buckling. For laterally unsupported beams, the design must verify that the buckling resistance exceeds the applied bending moment:
where:
is the buckling reduction factor,
is the plastic moment resistance.
The standard also insists on strict deflection limits to maintain rail alignment and prevent wheels from climbing or derailing:
where 
Integration with Other Eurocodes
EN 1993-6 is never used in isolation. It complements:
- EN 1993-1-1 for general steel design,
- EN 1991-3 for crane and machinery actions,
- EN 1990 for structural design basics, safety factors, and load combinations.
This ensures consistency in partial factors, load combinations, and limit state checks. For example, when calculating ultimate limit states or fatigue effects, the appropriate load factors must be applied to each action type according to EN 1991-3.
By cross-referencing multiple Eurocodes, designers create a robust, fully verified structure that satisfies strength, stability, serviceability, and fatigue requirements. It also provides assurance to clients, insurers, and regulatory authorities that the design meets pan-European standards.
Common Applications
Wherever there’s an overhead travelling crane or gantry crane — think fabrication halls, shipyards, or distribution centres — you’ll find the principles of EN 1993-6 at work.
These structures handle thousands of cycles each year, moving heavy components with pinpoint precision. Over time, the runway beams, rails, brackets, and connections bear the brunt of impacts and vibrations. Without sound design, you risk unplanned downtime, expensive repairs, and safety hazards.
By following the standard’s design equations and checks — from wheel loads:
to fatigue stress ranges:
— you ensure that every element can handle the daily demands placed on it, reliably and safely.
Final Thoughts
Crane supporting structures are one of the most demanding aspects of industrial building design. They quietly carry millions of tonnes across decades, often unnoticed until something goes wrong. By applying EN 1993-6 and its practical equations for loads, dynamic effects, buckling, and fatigue, you protect not just the equipment but your people, your productivity, and your peace of mind.
Need support with your next project?
At Product Development Engineers Ltd, we specialise in practical, code-compliant designs for crane supporting structures. From upfront design calculations and detailed fatigue assessments to final verification and drawing packages, we make sure your lifting operations stay safe, efficient, and EN 1993-6 compliant for years to come.
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