Enhancing Safety and Efficiency in Heavy Construction Machinery Operations: Design Aspects. The Second Edition of the EFFC/DFI Guide to Working Platforms

Due to their heavy weight and elevated center of gravity, the safe operation of heavy construction machinery, including drilling rigs and pile drivers, on soft ground conditions is related to significant challenges. While the dimensioning of working platforms in engineering practice often relies on empirical assumptions, these characteristics require the use of adequately dimensioned working platforms to prevent equipment overturns. Overturns can result in severe injuries, fatalities, property damage, production downtime, increased costs, and reputational harm. To address these risks, the European Federation of Foundation Contractors (EFFC) and the Deep Foundations Institute (DFI) have collaborated on the second edition of the “Guide to Working Platforms” for the design and construction of working platforms, set for publication in 2024. This edition aims to improve safety, simplicity, and productivity in on-site operations under challenging conditions, targeting geotechnical engineers, clients and all those involved in construction, including operatives on construction sites. An international consortium of industry, business, and research experts is developing the guide, focusing on three core areas: realistic ground pressure distributions beneath construction machinery (FRS#2), suitable geotechnical design methods for working platforms (FRS#3), and field test evaluations for verification and quality control of executed working platforms (FRS#1). The Institute of Geotechnical Engineering at the University of Stuttgart, was commissioned by DFI and EFFC, with research work on FRS#1 and FRS#3. This proposed paper will present the findings and recommendations based on these research projects. Field tests conducted across nearly 40 sites in Europe, the USA, and the UK revealed significant variability in results due to subbase and substrate conditions and test execution differences (FRS#1). The study identified various testing methods' sensitivities to material heterogeneity, underscoring the need for site-specific test selection and testing concepts. Recommendations on particularly suitable testing methods will be presented. The assessment of design methods for working platforms includes a comparison of calculation methods, the investigation of their sensitivity against input parameters as well as their application on representative case studies. The findings highlight significant deviation in required platform thicknesses depending on the chosen design method and emphasize the importance of a holistic approach of design methods including the selection of geotechnical input parameters, realistic track pressures, and appropriate calculation method and a related safety concept. As part of guidance formulated, it is demonstrated that the friction angles of granular platform layers and the subsoil shear strength decisively impact the required platform thickness.