This solution was essential to facilitate critical lifting operations from a position atop the slab, eliminating the need for costly ground-based alternatives and avoiding disruptions to the structure below.
The project was successfully delivered with:
✅ Zero structural compromise or safety incidents.
✅ Full compliance with engineering specifications and relevant codes.
✅ Crane operations executed successfully with no delays attributed to slab deflection or instability.
Legend Hire reinforced its capability to provide engineered propping solutions for high-risk, load-intensive applications in constrained environments.
Scope of Work
Design
- Engineering assessment of slab capacity and point load distribution from crane outrigger positions.
- Custom propping layout developed by Legend Hire engineers to match outrigger geometry and anticipated reaction forces.
- Modelling of:
- Dead loads (slab self-weight and finishes)
- Live loads (crane operational weight + dynamic lift loads)
- Lateral loads from crane slew and wind actions
- Compliance with:
- AS 3610 – Formwork for concrete
- AS 4100 – Steel structures
- AS/NZS 1170 series – Structural design actionsAS 3850 – Prefabricated concrete elements (where relevant)
Supply
- Deployment of Legend100T modular propping systems configured for high load concentration.
- Base spreader system using engineered timber sleepers to distribute outrigger loads to multiple props.
- A temporary propping system using Legend Hire Multi Props was also installed to support the travel path of the crane, ensuring slab integrity was maintained throughout all crane movements.
- All propping components were:
- Certified
- Delivered with engineering data sheets
Installation
- On-site setup by Legend Hire’s specialist install crew.
- Props placed directly beneath outrigger points, marked from slab survey.
- Timber packing and steel sole plates used to prevent point loading of slab.
- Installation sequence coordinated with crane contractor and site supervisor.
- Independent QA inspection prior to crane arrival.
Inspection & Handover
- Final inspection carried out by a qualified structural engineer.
- Comprehensive documentation provided including:
- Engineering certification
- SWMS and installation methodologyLoad compliance reportHandover checklist
- Installation Certification
Engineering Considerations
Load Calculations
- Crane outrigger loads assessed based on Liebherr technical datasheets (gross weight + lift capacity).
- Consideration of dynamic effects:
- Slew moments
- Jib extension torque
- Wind loading during lift
- Propping layout optimized to:
- Avoid services beneath the slab
- Minimize impact to ground-level operations
Safety Measures
- Props are certified, anti-buckling clips, and safety tags.
- Exclusion zones enforced during crane operation.
- All activities performed under a detailed Safe Work Method Statement (SWMS) specific to crane back propping.
- On-site toolbox talks and supervision maintained during install and removal.