Overview
ISO 8686-4:2005 - "Cranes - Design principles for loads and load combinations - Part 4: Jib cranes" applies the general rules of ISO 8686‑1 to jib-type cranes. The standard defines the loads, load combinations and proof-of-competence calculation rules appropriate for the steel structures of jib cranes (excluding offshore, tower, mobile, railway, gantry and overhead cranes covered elsewhere). It gives guidance for combining inertia, wind, climatic, emergency and exceptional actions to discover the most unfavorable stress conditions.
Key topics and technical requirements
- Scope and references: Builds on ISO 8686‑1 and refers to wind assessment in ISO 4302.
- Load categories: Masses (crane and gross load), acceleration/inertial effects (hoisting, slewing, travelling), wind (in‑service and out‑of‑service), snow/ice, temperature, skewing, test and buffer loads, tilting, foundation excitation and emergency/failure actions.
- Combination principles: Loads are combined to produce maximum unfavourable effects; simultaneous accelerations of up to two drives are generally assumed; side loading (e.g., due to reeving or jib geometry) must be included when present.
- Dynamic amplification (φ) and partial/allowable factors (γ): The standard provides tables of dynamic amplification factors (φ) and allowable or partial load factors (γ) for both the allowable stress and limit state methods. Example values are given for common cases (e.g., φ = 1.5 for hoisting inertia in certain conditions; higher φ where backlash exists). The resistance coefficient for limit-state combinations is specified.
- Proof-of-competence methods: Permits either the allowable stress method or the limit state method, with tables listing the applicable load combinations, coefficients and dynamic factors.
- Column strength & stability: Annex A addresses column strength considerations for members under axial compression and links column formula selection to the applicable factor usage.
Practical applications
- Perform structural design checks and proof-of-competence calculations for jib crane steelwork.
- Size and verify jib members, columns, connections and foundations against combined loads (inertia, wind, emergency loads, etc.).
- Specify testing criteria (dynamic/static test loads), braking/drive torque requirements and conservative design assumptions (simultaneous accelerations, side loading).
- Support procurement and manufacturer–purchaser agreements by clarifying which load cases and factors apply.
Who should use this standard
- Crane designers and structural engineers working on jib cranes
- Crane manufacturers and OEM design teams
- Third‑party assessors, certification bodies and safety inspectors
- Purchasing engineers specifying performance and test requirements
Related standards
- ISO 8686‑1:1989 - Cranes - Design principles for loads and load combinations - Part 1: General
- ISO 4302:1981 - Cranes - Wind load assessment
Keywords: ISO 8686-4:2005, jib cranes, design principles, loads and load combinations, proof-of-competence, dynamic amplification, allowable stress method, limit state method, crane design.
