ISO 8686-5:2017

Overview

ISO 8686-5:2017 - "Cranes - Design principles for loads and load combinations - Part 5: Overhead travelling and portal bridge cranes" applies the general principles of ISO 8686‑1 specifically to overhead travelling and portal (bridge/gantry) cranes as defined in ISO 4306‑1. The standard gives rules and specific factor values for calculating loads, dynamic effects and load combinations used in structural design, proof of competence and safety verification of bridge and gantry cranes.

Key topics and requirements

• Scope and application: Establishes how ISO 8686‑1 is applied to overhead travelling and portal bridge cranes and provides the numerical factors and assumptions needed for design calculations.
• Classification of loads: Defines regular, occasional and exceptional loads and how each is treated for strength, stability and fatigue assessment.
• Dead weight and gravity effects: Dead loads are multiplied by a factor ϕ1 (e.g., a = 0.10 → ϕ1 = 1.10 for unfavourable effects; a = −0.05 → ϕ1 = 0.95 for favourable effects).
• Hoisting dynamic effects: Provides methods to determine the hoisting dynamic factor ϕ2:
  • Selection by hoisting class (HC1–HC4) based on hoisting speed and behaviour.
  • Calculation options include complete dynamic simulation, simplified formulae for rope or chain hoists, or measured values from equivalent cranes.
• Travelling and track effects: Prescribes factors for dynamic loads from travelling on uneven rails or roadways (ϕ4), with specific values for continuous welded tracks vs. tracks with notches.
• Skewing and lateral loads: Addresses loads caused by skewing, including new calculation methods for rigid or flexible bridge/gantry systems (see informative Annex A).
• Exceptional scenarios: Rules for test loads, buffer forces, emergency cut‑outs, failure cases and lifting‑force limiter events.
• Load combinations and factor application: Guidance for combining acceleration, sequential movements and other effects when forming design load cases.

Applications and users

ISO 8686‑5:2017 is intended for:

• Crane designers and structural engineers performing strength, stability and fatigue analyses.
• Crane manufacturers, fabricators and component suppliers for design verification.
• Certification bodies, inspection authorities and safety assessors validating compliance.
• Facility owners and maintenance teams specifying load assumptions for procurement, testing and safe operation.

Practical uses include structural sizing, selecting ropes/chains, wheel/track design, dynamic simulation inputs and proof‑of‑competence calculations.

Related standards

• ISO 8686‑1:2012 (general design principles for loads and combinations)
• ISO 4306‑1 / ISO 4306‑5 (crane vocabulary / classifications)
• ISO 4301‑1, ISO 4302 (classification & wind load assessment)
• ISO 12488‑1, ISO 20332 (tolerances & steel structure competence)

Keywords: ISO 8686-5:2017, overhead travelling crane, portal bridge crane, crane loads, load combinations, hoisting dynamic factor, skewing loads, crane design standard.