Norwegian Geotechnical Institute (NGI) Digital Archive
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Cost and carbon implications of different foundation solutions - Desk study of foundation design for a bridge and a building in Norway
Get PDFThe choice of method and materials for pile foundations in Norway often builds on the experience of the involved parties and a preference of solutions with fewer, high-capacity piles compared to more, low-capacity piles. In many cases the foundations do not get optimized with regard to resource use and cost. Timber piles, which had a long tradition in the country, are now rarely used. In urban environments, where marine clays are the dominant geological surface formation, shallow building foundations on stabilized ground could be considered. Yet, piled solutions to bedrock are usually chosen due to the concerns related to settlements induced by other building projects.
To investigate whether the current practice could be improved, a desk study was conducted comparing cost and carbon emissions for four different foundation solutions for a bridge foundation in sand (steel pipe piles, HP steel pile, prefabricated concrete piles and timber/concrete combination piles). For a typical building project in Norway, a direct foundation on stabilized clay was compared to the usually chosen piles to bedrock solution. It is discussed what alternatives might be feasible with respect to practicality, robustness, costs, sustainability and environmental issues. In particular, the acceptable movements in the overlying structure will determine the feasibility of more environmentally friendly solutions
Research Plan 2023–2025
Get PDFSnow avalanches are a frequent and significant natural hazard in Norway. Each year, avalanche events result in fatalities, evacuations, interruptions, and damage to infrastructure networks such as roads, railways, and electrical transmission lines. This combines to a substantial impact on the livelihoods of the people living and working in mountainous areas or also along the fjords in Norway. Persistent avalanche hazard in steep terrain is a major factor considered during land-use planning and development. During the snow season, variations in the avalanche danger identified in regional and site-specific bulletins influence the operation of the transportation networks and the safety of workers in these areas. Applied research on avalanches and their societal impacts has been conducted at the Norwegian Geotechnical Institute (NGI) since 1973. The year 2023 will mark the 50 years anniversary of this research project. The research has been funded in part by an annual grant from the Norwegian parliament administered by the Norwegian Water Resources and Energy Directorate (NVE). Recent research activities have improved our understanding of avalanche formation, movement and impacts from avalanches. For example, enhanced knowledge of the individual processes leading to avalanche initiation, avalanche dynamics and avalanche impacts have been applied to develop tools for prediction of avalanche events, runout distance and impact pressures. While much has been accomplished within the avalanche research community in recent years, many key questions remain. Research in this area becomes increasingly important as a changing climate will vary the frequency and behaviour of avalanche events. In addition, the transfer of resent research outcomes into common practise is an ongoing challenge which needs continuous attention. This project plan will: Present the research goals for the 2023–2025 period. Outline the project organisation. Present the work-package structure and specific research tasks to be undertaken by the applied avalanche research group at NGI over the next three years.NVE (Norges vassdrags- og energidirektorat
Calculation of soil volume loss caused by drilling of anchors
Get PDFAccurate prediction of ground settlements related to deep supported excavations or foundation works are key in risk assessments of vulnerability of neighboring assets. Several studies show that rotary percussive duplex drilling of casings for tieback anchors and piles can cause substantial local soil volume loss (cavities) around the casings resulting in ground settlements. This paper presents FE back-analysis of a well-documented deep supported excavation in soft clay to investigate the influence from such soil volume loss on the surrounding ground. The analysis demonstrates a simple approach to estimate potential installation effects from overburden drilling by modelling volume loss in specified soil clusters. The method can be implemented in early-planning risk assessments in building projects to assess influence areas and suitability of drilling methods.Calculation of soil volume loss caused by drilling of anchorspublishedVersio
REMEDY - et BegrensSkade prosjekt. Sluttrapport
No full textBegrensSkade-prosjektene har vært bransjeomfattende forskningsprosjekt finansiert av Norges forskningsråd samt private aktører i byggenæringen. Det første BegrensSkade prosjektet startet i 2012, og med avslutningen av REMEDY (BegrensSkade II) har det totalt pågått 10 år av forskning innenfor temaer relatert til skadeforebygging i forbindelse med grunnarbeider
Load envelope concept of offshore wind turbine monopile with the allowed inclined angle in sand
Get PDFMonopiles are the economic choices in shallow water as the foundations of offshore wind turbines (OWTs). Maximum allowed rotation h¼0.25�is set as the criterion in the serviceability limit state design. However, the allowed load combinations of monopiles in sand are not fully revealed and understood satisfying the criterion. In this paper, load envelop concept to ensure the allowed monopile rotation less than 0.25�was proposed to understand all possible load combinations on monopiles for the OWTs. Finite element models based on the sand hypoplastic model with inter- granular strain were established. After verification with the centrifuge results, different load–dis-placement curves were acquired by changing loading paths to acquire the envelope surfaces meeting the criterion. Finally, the most likely load combinations of the OWTs were particularly analysed. Under the condition with h¼0.25�, the allowed horizontal loads and the bending moments are closely coupled. The calculated envelop curves composed of maximum allowed loads can be well fitted and described by the cubic function. This note provides a method to obtain load combinations with allowed inclinations, which is beneficial to understand the load states of monopile for OWTs.publishedVersio
Shared mooring systems for offshore floating wind farms: A review
Get PDFOffshore wind energy, as a form of renewable power, has seen rapid development in recent years. While fixed-bottom wind turbines are typically used in water depths less than 50 m, the utilization of floating offshore wind turbines (FOWTs) becomes essential for deeper waters. Secure and effective mooring systems play a crucial role in making FOWTs commercially viable. The concept of a shared mooring system offers an innovative solution for deploying floating wind farms in clusters or arrays, which can reduce overall construction costs for large-scale floating wind farms. It is imperative to optimize the shared mooring arrangement for maximum cost-effectiveness and wind farm stability. However, implementing a shared mooring system introduces complexity to the dynamics of FOWTs, requiring the development of advanced simulation tools to meet modelling requirements. Under the shared mooring arrangement, mooring lines and anchors face more significant challenges, such as chain-seabed interactions, soil cyclic weakening, and anchor out-of-plane loading, which underscore the need for innovative, reliable, and efficient shared anchor designs. This article offers an overview of the current research status on shared mooring systems for floating wind farms, which might serve as a valuable reference for the construction of large-scale floating wind farms worldwide.Shared mooring systems for offshore floating wind farms: A reviewpublishedVersio
Deliverable 4.5: CO2 storage assessment – numerical simulation of the India case study
No full textA study of possible CCS application at the onshore field Baghewala,Bikaner Nagaur Basin India is discussed. The primary analysis includes identification of key reservoir and caprock units for storage and monitoring. Furthermore, a simple 3D homogeneous model based upon petrophysical properties from well data is generated and simulated under different injection rates of CO2 to identify the associated changes in pore pressure. Based upon the learnings from this model, a field scale model is generated to present a more realistic study for CO2 saturation and pore pressure changes in identified reservoir units. The Geomechanical properties such as Young Modulus, Shear Modulus, Bulk Modulus and Poisson ratio is obtained from compressional and shear velocity measurement from the downhole wireline log. This gives a description of geomechanical parameters in the reservoir and caprock zones.European CommissionpublishedVersio
Numerical study on the behaviour of horizontal anchor using upgraded SANISAND-MS
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Differentiating reefal ridges from relict coastal ridges: Lessons from the seismic geomorphologic study of buried Miocene buildups (North West Shelf, Australia)
Get PDFLinear buildups formed in tropical carbonate environments are often interpreted as bioconstructed reefs. Nevertheless, coastal processes can also form extensive sedimentary ridges exhibiting buildup morphologies. This study investigates two Miocene ridges developed along the Australian North West Shelf using 3D seismic and well data. Ridge 1 is ca. 30 m thick and >60 km long, and it is made of foraminiferal pack-grainstones. It protects a lagoon with pinnacle morphologies. Ridge 2 is ca. 150 m thick and >80 km long. It is composed of quartz sand forming lobes. Both ridges have a continuous curvilinear front and are in a mid-shelf setting. They mimic the modern Australian coastline. It is then proposed that Ridge 1 is either: (1) a barrier reef developed on a drowned shoreline, or (2) stacked carbonate aeolianites and beachrocks acting as a barrier. Ridge 2 is interpreted as stacked deltaic sands. This study demonstrates that lithified and buried coastal features of carbonate and siliciclastic nature can form extensive ridges exhibiting buildup morphologies. It is proposed that ridges formed by stacked coastal features are overall continuous with a curvilinear front, while reefal ridges are more discontinuous and exhibit deeper and more stable passes.Differentiating reefal ridges from relict coastal ridges: Lessons from the seismic geomorphologic study of buried Miocene buildups (North West Shelf, Australia)publishedVersio