There are clear advantages in the establishment of reliable, direct cone penetration test (CPT) based methods for assessment of the axial capacity of driven piles. These advantages motivated the formation of a joint industry project (JIP) under the management of the Norwegian Geotechnical Institute (NGI), which initially led to the creation of a unified database of high-quality pile load tests in sand and clay. The unified database has the consensus approval of representatives of the profession and personnel in multiple companies from the offshore energy sector. This paper presents a component of the research from the second phase of the JIP, which had the objective of developing a new CPT-based method for driven piles in clay to unify several CPT-based methods that are in use today. First, a rational basis for the CPT-based formulation is described, using trends from instrumented pile tests; the description facilitates an understanding of the approach and illustrates its empirical nature and limitations. The unified database was used to calibrate the formulation and it led to good predictions for an independent database of pile load tests and for measured distributions of shaft friction.

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This paper outlines the development of a new ‘Unified’ CPT-based method for estimating the axial capacity of driven piles in sand. The method adapts key features of the four CPT-based methods currently in the API and ISO guidelines. The new method was calibrated with the Unified database of pile load tests developed as part of an earlier joint industry research project (Lehane et al. 2017). Key factors known to influence pile capacity are incorporated in the new Unified method formulation, including (i) the degree of soil displacement (plugging) during installation, (ii) the influence of relative pile tip depth, (iii) sand-pile interface friction angle, (iv) changes in radial stress during loading and (v) the influence of loading direction. It is shown that the new method provides more reliable predictions of the capacities of the pile load tests in the Unified database than any of the existing axial pile capacity design methods in the API and ISO guidelines.@en

Roskilde University (Denmark) hosted a November 2015 workshop, Environmental Risk—Assessing and Managing Multiple Risks in a Changing World. This Focus article presents the consensus recommendations of 30 attendees from 9 countries regarding implementation of a common currency (ecosystem services) for holistic environmental risk assessment and management; improvements to risk assessment and management in a complex, human-modified, and changing world; appropriate development of protection goals in a 2-stage process; dealing with societal issues; risk-management information needs; conducting risk assessment of risk management; and development of adaptive and flexible regulatory systems. The authors encourage both cross-disciplinary and interdisciplinary approaches to address their 10 recommendations: 1) adopt ecosystem services as a common currency for risk assessment and management; 2) consider cumulative stressors (chemical and nonchemical) and determine which dominate to best manage and restore ecosystem services; 3) fully integrate risk managers and communities of interest into the risk-assessment process; 4) fully integrate risk assessors and communities of interest into the risk-management process; 5) consider socioeconomics and increased transparency in both risk assessment and risk management; 6) recognize the ethical rights of humans and ecosystems to an adequate level of protection; 7) determine relevant reference conditions and the proper ecological context for assessments in human-modified systems; 8) assess risks and benefits to humans and the ecosystem and consider unintended consequences of management actions; 9) avoid excessive conservatism or possible underprotection resulting from sole reliance on binary, numerical benchmarks; and 10) develop adaptive risk-management and regulatory goals based on ranges of uncertainty.@en