Crane Girder & Runway Beam Design: EOT & HOT Crane Structures for Industrial Buildings
In heavy industrial facilities such as steel plants, fabrication shops, foundries, automobile plants, and engineering workshops, overhead cranes are the backbone of material handling. The crane girder and runway beam system that supports these cranes is one of the most dynamically loaded, fatigue-critical structural systems in any industrial building. A poorly designed crane runway causes premature fatigue cracking, misalignment, excessive deflection, and ultimately costly unplanned shutdowns.
What is a Crane Girder & Runway Beam?
A crane girder is the main horizontal beam spanning between crane columns on which the crane rail is mounted and that directly carries crane wheel loads. The runway beam system includes the crane girder, rail, rail fastenings, end stops, conductor rail supports, and all connections to the supporting crane columns forming the complete track on which the overhead crane travels.
At BestGrid.in, we design and detail crane girders and runway beam systems for EOT and HOT cranes, delivering IS 800- and IS 807-compliant, fabrication-ready designs that maximise crane performance and structural reliability.
EOT vs HOT Cranes: Key Differences
The two most common overhead crane types in Indian industry are Electric Overhead Travelling (EOT) cranes and Hand Operated Travelling (HOT) cranes, each with distinct structural implications:
| Feature |
EOT Crane |
HOT Crane |
| Operation | Electric motors, pendant or remote | Manual chain pull, hand-operated |
| Capacity | 1 tonne to 500+ tonnes | Typically up to 10 tonnes |
| Dynamic Factor | Higher motors generate impact & surge | Lower: slow manual operation |
| Fatigue Class | Higher class: more cycles per year | Lower class: fewer cycles |
| Girder Size | Larger: heavier loads & fatigue | Smaller lighter loads |
| IS Code | IS 807, IS 800, IS 3177 | IS 807, IS 800 |
Crane Loads on Runway Beam IS 807
Crane runway beams are subjected to a unique combination of static and dynamic loads that must all be considered per IS 807:
- 📌 Vertical wheel load static crane weight + rated load, multiplied by dynamic impact factor
- 📌 Dynamic impact factor 1.10 to 1.25 depending on crane class and speed per IS 807
- 📌 Lateral surge load: horizontal force from crane travel acceleration/braking (10% of lifted load + crab)
- 📌 Longitudinal braking force: along runway from crane bridge braking (5% of maximum static wheel load)
- 📌 Skewing force: lateral force from crane misalignment during travel
- 📌 Fatigue load spectrum: cumulative loading from repeated crane cycles over design life
Types of Crane Girders
01
Hot-Rolled I-Section Girder (ISMB / ISWB)
Used for light cranes up to 10 tonnes capacity and spans up to 8 m. Standard hot-rolled sections are economical and fast to fabricate; the rail is mounted directly on the top flange. The top flange width must be sufficient to accommodate the rail and provide lateral stability.
02
Plate Girder (Fabricated I-Section)
A custom-fabricated I-section from plates, used for medium- to heavy-duty cranes (10–100+ tonnes) and longer spans. The top flange is made wider and thicker than the bottom flange to accommodate the rail load and provide lateral stability against horizontal surge forces. Web stiffeners are provided at regular intervals and at crane rail positions.
03
Box Girder
A closed rectangular steel box section providing very high torsional stiffness and bending capacity for very heavy cranes (100+ tonnes) and long spans. Box girders are used where deflection control is critical and biaxial bending from large horizontal surge forces must be efficiently resisted.
04
Underslung Monorail Beam
A single beam on which a hoist travels on the lower flange, used for light lifting (typically up to 5 tonnes) along a fixed linear path. Monorail beams are designed for bending, shear, and lateral-torsional buckling of the bottom flange under hoist-wheel loads.
Fatigue Design: Why It Is Critical
Crane girders experience thousands to millions of load cycles over their design life, making fatigue the governing design criterion in most cases:
⚠️ Critical fatigue design requirements for crane girders per IS 800 Annex F:
- All welds in the tension flange zone must be full-penetration butt welds no fillet welds in high fatigue stress zones
- No attachments, holes, or notches in the tension flange; stress concentrations drastically reduce fatigue life
- Web-to-flange welds must be continuous fillet welds; no intermittent welding in fatigue-critical zones
- Top flange-to-rail interface must have no welding directly on the top flange surface
- Crane girder splices must be located at low bending moment positions, not at mid-span
Crane Rail Selection & Fixing Details
Crane rail selection and fixing considerations:
- 📌 Rail section selected based on crane wheel load and wheel diameter (CR series per IS 3443)
- 📌 Rail-to-girder fixing: clip-type fixings (never weld rail directly to flange); allow rail replacement
- 📌 Rail alignment tolerance ±5 mm span tolerance, ±1 mm level difference between rails
- 📌 Rail joints fishplate joints or welded joints with ground smooth profile
- 📌 Rail pad rubber or plastic pad between rail and girder top flange to reduce impact transmission
- 📌 End stops buffer end stops at each end of runway designed for crane impact load
Crane Column & Bracket Design
Detail 1
Stepped Column (Above & Below Crane Rail Level)
In dedicated crane bays, columns are designed with a stepped profile: a heavier section below crane rail level and a lighter section above. The stepped column efficiently transfers crane girder reactions, while the upper column independently carries roof loads.
Detail 2
Crane Bracket (Corbel)
In existing buildings where a crane is being added, a welded bracket (corbel) is attached to the column web to support the crane girder. The bracket must be designed for the full vertical reaction of the crane girder plus the moment due to eccentricity, and the column must be checked for the additional bracket load.
What Is Included in Our Crane Girder Design Package?
| # |
Deliverable |
Purpose |
| 1 | Crane Load Analysis | IS 807 wheel loads, impact, surge & braking |
| 2 | Girder Design Calculation | Bending, shear, deflection & fatigue check |
| 3 | Crane Girder Fabrication Drawing | Plate sizes, stiffener layout & weld details |
| 4 | Rail & Fixing Details | Rail section, clip fixing & pad specification |
| 5 | Column & Bracket Design | Stepped column or bracket design & detailing |
| 6 | End Stop & Buffer Details | Runway end buffer design for crane impact |
Frequently Asked Questions
What is the difference between an EOT and HOT crane?
An EOT (Electric Overhead Travelling) crane uses electric motors for all movements and is used for heavy, frequent lifting operations. A HOT (Hand Operated Travelling) crane is manually operated using chain hoists and is used for lighter, infrequent lifting. EOT cranes impose higher dynamic loads and fatigue demands on the runway structure.
Why is fatigue design critical for crane girders?
Crane girders experience thousands to millions of load cycles over their service life, making fatigue the governing design criterion. Without proper fatigue detailing, cracks initiate at weld toes, stress concentrations, and attachment points, leading to premature failure at load levels well below the static design capacity.
What is the maximum deflection allowed for crane girders?
Per IS 800 and IS 807, the maximum vertical deflection of crane girders under wheel loads is span/500 for EOT cranes and span/750 for precision cranes. Excessive deflection causes rail misalignment, increased wheel wear, and crane travel problems.
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