EOT Crane Gantry Girder Design and Structural Calculations

Electric Overhead Travelling (EOT) cranes are essential for heavy material handling in manufacturing plants, foundries, and steel yards. However, the movement of a loaded crane introduces significant dynamic forces, including vertical impact, lateral surge, and longitudinal tractive forces. When working with a leading EOT crane manufacturer in Chennai, runway stability is paramount. 1. Dynamic Loading Calculations The gantry girder must support the combined weight of the crane bridge, trolley, and rated load. - Vertical Impact: IS 875 mandates adding 25% to the static wheel loads for electric overhead cranes to account for acceleration and deceleration impacts. - Lateral Surge: Transverse forces caused by the acceleration of the crane trolley. This is calculated as 10% of the combined weight of the lifted load and trolley, distributed along the runway rails. - Tractive Forces: Longitudinal forces caused by crane braking or acceleration, calculated as 5% of the static wheel loads. In the engineering hubs of Sriperumbudur and Kanchipuram, fabricating EOT crane runway systems takes 3 to 5 weeks, with costs starting from ₹1,50,000 to ₹4,50,000 per bay. All runway beams adhere strictly to IS 800 structural welding guidelines. 2. Fatigue Limits and Girder Design Because EOT cranes operate continuously, the gantry girder undergoes cyclic stress. The design must account for fatigue limits to prevent cracking at connections. - Steel Grade: We use high-yield strength steel plates (IS 2062 Grade E350) with high fatigue limits for the web and flanges of built-up gantry sections, reinforcing heavy steel structures. - Web Buckling and Torsion: Gantry girders are subjected to eccentric loads. We install vertical stiffeners at load points to prevent web buckling. 3. Laser-Guided Runway Rail Alignment Misaligned rails cause wheel wear, crane crabbing, and excessive structural stress. Deepika Builtech utilizes optical levels and laser rangefinders to align gantry rails, maintaining span tolerances within ±2mm over the entire run.