PLENARY SESSION 4: A Critical Look at Working Platform Design-PPT Presentation

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The panel discussion emphasized that working platforms for piling rigs and cranes must be designed using a calibrated combination of equipment loading, ground-bearing capacity and an appropriate safety approach.<br /><br />The speakers compared loading methods and warned that they are not interchangeable. FPS loading considers multiple operating conditions and full 360-degree rig rotation, while some published loading tables cover only limited scenarios and may underestimate critical pressures. Simplified bearing-capacity methods, such as BR470, can be useful, but their assumptions and safety factors require rigorous calibration and verification.<br /><br />Platform design is particularly sensitive to the strength of granular fill. Small differences in friction angle can substantially change the required platform thickness, while a few plate-load tests may not capture site variability. A proposed alternative uses a light-weight deflectometer (LWD) to provide faster, broader coverage and an estimate of friction angle compatible with BR470. Early trials were reported as promising, with further testing planned.<br /><br />Practical lessons included using suitable materials, managing water, respecting equipment grade limits and manufacturer recommendations, and avoiding unapproved changes or workarounds. Risks include soft spots, poor compaction, incorrect equipment load data, unmaintained platforms, excavations, and unsuitable access routes. Platform failures can also result from inadequate inspection or construction under programme and cost pressure.<br /><br />Design documentation should clearly state allowable loads, operating restrictions, access and edge-distance limits, and maintenance requirements. An inspection and test plan should cover subgrade checks, proof rolling, material specifications, layer placement, compaction, dimensions and ongoing maintenance. The panel also stressed that certificates and clear communication between designers, contractors and operators are essential to safe platform use.

Keywords

piling rigs

cranes

working platforms

ground-bearing capacity

platform design

FPS loading

BR470

light-weight deflectometer

friction angle

inspection and test plan