Understanding the Next Step After Reaching DWP Reaching the Design Working Period does not automatically mean that a crane must be removed from service. Instead, it signals that the original design assumptions regarding fatigue and duty have been fulfilled. At this stage, continued operation requires structured evaluation rather than routine maintenance alone. This is where […]
When Is a General Overhaul Required? Read More »
Why Lifetime Is Evaluated Differently When discussing the Design Working Period, it is important to distinguish between two fundamentally different components of a crane: The load-bearing structure The hoisting mechanism Although they operate together, their lifetime evaluation is based on different principles. Structural Lifetime: Cycle-Based Assessment The crane structure, including: Main girders End carriages Load-bearing
Crane Structure vs Hoist Mechanism: Different Lifetime Approaches Read More »
Cycles and Load Spectrum in DWP Assessment The lifetime of a crane structure is governed by more than just its rated capacity. Design Working Period is fundamentally influenced by two key parameters: The number of operating cycles The load spectrum during those cycles Both factors must be considered together to understand cumulative structural demand. Number
Two Duty Factors That Govern Crane Lifetime Read More »
The Difference Between Years in Service and Structural Usage It is common to describe cranes as “10-year-old” or “20-year-old” equipment.However, calendar age alone does not determine whether a crane is close to the end of its safe working life. In reality, structural lifetime depends on how intensively the crane has been used. Time in Service
Why Calendar Age Does Not Define Crane Lifetime Read More »
Understanding the Real Lifetime of a Crane A crane is not designed for unlimited use.Its structural components and mechanisms are engineered for a finite working life, defined not by calendar years, but by operational usage. This concept is known as the Design Working Period (DWP). Lifetime Is Measured in Cycles, Not Years It is common
What Is Design Working Period (DWP)? Read More »
When Web Slenderness Governs Structural Resistance In crane girder design, the web does not carry bending alone.It also transfers significant shear forces between supports and wheel load positions. For slender webs, shear resistance may be governed not by material yielding, but by shear buckling. According to EN 13001-3-1, shear stability must be verified explicitly when
Shear Buckling of Crane Webs Read More »
Local Effects Beneath the Rail in Crane Girders While global bending governs overall stress in a crane girder, wheel loads introduce highly localized effects that must be assessed separately. Under each wheel, concentrated vertical forces generate transverse compression in the web and flange region beneath the rail. This local stress state differs significantly from global
Transverse Compression Under Wheel Loads Read More »
Why Different Plate Elements Behave Differently In crane girder design, not all plate elements respond to compression in the same way.The web and the compression flange are subjected to different stress states, boundary conditions and instability mechanisms. Understanding these differences is essential for realistic buckling verification according to EN 13001-3-1. Stress State in the Web
Web Buckling vs Flange Buckling Read More »
Plate Buckling in Crane Girders In crane girder design, material yield strength is not always the governing resistance criterion.For slender plate elements, instability may occur before the material reaches its yield stress. This phenomenon is known as plate buckling and plays a central role in crane girder verification according to EN 13001-3-1. Slender Plate Elements
Plate Buckling in Crane Girders Read More »
Serviceability Requirements According to FEM Practice In crane girder design, strength and stability are not the only governing criteria. Even when stresses and buckling checks are satisfied, excessive deflection may impair crane operation. Deflection control is therefore a fundamental serviceability requirement in crane main girder design. Why Deflection Matters in Crane Structures Unlike ordinary floor
Deflection Criteria for Crane Main Girders Read More »