Design, Construction and Verification of Temporary Working Platforms â€“ Australian & New Zealand Good Industry Practice-Paper

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Temporary working platforms for cranes and piling rigs are high-risk engineered structures. Inadequate design or construction can cause ground deformation and equipment overturning. Safe performance depends on realistic plant load assessments, suitable ground data, appropriate design methods, and documented verification.<br /><br />Plant loading must reflect project-specific operations, including lifting or drilling, travel, assembly and disassembly, and loading or unloading. Track pressures may vary between activities, and loads may also be transferred through outriggers or a mast foot. Any assumptions that differ from equipment manufacturers’ recommendations must be assessed by experienced personnel and clearly communicated to site crews. Dynamic effects, particularly for high-centred piling rigs, should also be considered.<br /><br />Design requires a site-specific ground model based on adequate investigation of soil layers, strength, and groundwater. Shallow ground conditions are especially important, and investigation depth should account for the plant’s pressure influence and the design checks required. Groundwater variation and weaker layers must not be overlooked.<br /><br />BRE470 is widely used in Australia and New Zealand. It assesses bearing capacity and relies mainly on punching resistance in the platform. The alternative TWf2019:02 method applies partial factors, checks both bearing capacity and immediate settlement, and accounts for multiple soil layers and load spread, but not punching resistance. More complex ground conditions may require advanced numerical analysis. Platform fill properties, placement, compaction, aggregate size, and contamination risks must be specified.<br /><br />Before use, platforms should be verified and certified by suitably qualified, experienced professionals. Verification may include multiple plate load tests and compaction testing; proof rolling may be suitable for low-risk platforms at the verifier’s discretion. Certification should document design assumptions, plant loads, platform dimensions, limitations, access and assembly arrangements, edge restrictions, maintenance, and any settlement limits.<br /><br />The paper’s central recommendation is that competent geotechnical practitioners oversee the design, construction verification, and certification, with operational restrictions communicated clearly to all relevant personnel.

Keywords

temporary working platforms

crane safety

piling rigs

ground deformation

plant load assessment

bearing capacity

ground model

BRE470

TWf2019:02

geotechnical verification