Crane End Stop Weld

Core Engineering Principle: Crane End Stop Design

This calculation follows the principle that when a moving crane bridge hits an end stop, the kinetic energy must be safely absorbed without structural failure of either the crane or the runway system.

1. Impact Load Calculation

• A moving crane has kinetic energy that must be dissipated when it hits the end stop
• The calculation uses empirical formulas from AIST (Association of Iron & Steel Technology) standards
• The effective weight (We) accounts for the fact that not all crane components contribute equally to impact
• The impact force (Fa) is calculated based on this effective weight and standardized impact factors

2. Dynamic vs. Static Loading

• This isn't just about supporting the crane's weight - it's about absorbing impact energy
• The force applied to the bumper creates a moment (bending force) in the end stop beam
• The moment arm is the height (H) from the runway centerline to where the bumper contacts

3. Beam Bending Analysis

• The end stop beam (W6x20 steel section) must resist the bending moment without yielding
• Uses standard steel design principles: Applied moment (Ma,x) must be less than allowable moment capacity
• The allowable moment uses the plastic section modulus (Zx) and appropriate safety factors (Ω)

4. Connection Design (Weld Analysis)

• The end stop must be welded to the runway beam strong enough to transfer the impact forces
• Blodgett method analyzes weld stresses considering both direct force and bending moment
• The weld size must be adequate for the calculated stresses but also meet minimum practical requirements

5. Practical Constraints

• Minimum weld sizes based on material thickness (you can't make welds too small to be reliable)
• Maximum weld sizes limited by material thickness (you can't weld thicker than the base metal)
• The final weld size is governed by whichever constraint is most restrictive

6. Crane Classification System

• Different crane classes (A, B, C, D) have different service requirements
• Higher classes need more robust end stops due to more frequent and severe impacts
• The table shows recommended beam sizes for different crane classes

This is essentially designing a "shock absorber" system - the end stop must be strong enough to stop the crane safely without damaging the runway structure, similar to how highway guardrails must absorb vehicle impact energy without failing.