1,177 research outputs found
Letter from J. E. Gavin to Louis C. Cramton regarding Sale of Bright Angel Trail
No full textLetter from J. E. Gavin to Louis C. Cramton regarding the Bright Angel Trail controversy, including newspaper clipping
Letter from B. F. Gavin (for Carl Hayden) to Stephen Mather, National Park Service
No full textLetter from Mrs. B. F. Gavin to Stephen Mather regarding the sale of Bass properties to the Santa Fe Railroad Company
Experimental and numerical investigation of the effect of vertical loading on the lateral behaviour of monopiles in sand
No full textThe influence of combined loading on the response of monopiles used to support offshore wind turbines (OWTs) is investigated in this paper. In current practice, resistance of monopiles to vertical and lateral loading is considered separately. As OWT size has increased, the slenderness ratio (pile length, L, normalised by diameter, D) has decreased and foundations are tending towards intermediate footings with geometries between those of piles and shallow foundations. Whilst load interaction effects are not significant for slender piles, they are critical for shallow footings. Previous research on pile load interaction has resulted in conflicting findings, potentially arising from variations in boundary conditions and pile slenderness. In this study, monotonic lateral load tests were conducted in a geotechnical centrifuge on vertically loaded monopiles in dense sand. Results indicate that for piles with L/D = 5, increasing vertical loading improved pile initial stiffness and lateral capacity. A similar trend was observed for piles with L/D = 3, when vertical loading was below 45% of the pile’s ultimate vertical capacity. For higher vertical loads considered, results tended towards the behaviour observed for shallow footings. Numerical analyses conducted show that changes in mean effective stress are potentially responsible for the observed behaviour
Letter from J. E. Gavin (for Senator Hayden) to Roy W. James, Michael Hanley and H. A. Montgomery
No full textLetter from J. E. Gavin on behalf of Carl Hayden writing in regards to the insurance claims filed with the National Park
The first statewide, open access dataset tracking public records requests in New Jersey
No full textState freedom of information laws are vital mechanisms for providing public access to government records and supporting civic engagement through the effectuation of a public policy of transparency at the state level within the United States, not unlike their federal counterpart, the Freedom of Information Act (FOIA). New Jersey state law facilitates public access to government records under the Open Public Records Act (OPRA). Codified at N.J.S.A. 47:1A-1 et seq., OPRA applies to state, county and local public authorities but exempts the judicial and legislative branches from its disclosure requirements. Since OPRA took effect in 2002, it has been difficult to track the full extent of law's impact across New Jersey's 21 counties, 565 municipalities, and numerous state agencies, school districts and independent authorities, all of which must individually respond to requests under the law. To the best of the author's knowledge, no official source has compiled detailed metadata tracking the content and disposition of OPRA requests at the state, regional and municipal levels within New Jersey using individual requests, and authorities rarely proactively disclose their responses to requests they receive, necessitating further data collection to support research into the impacts of this law. This article presents the OPRAmachine dataset: data containing detailed metadata on public records requests submitted to state & local public authorities in New Jersey since October 2017 collected through the implementation of information and communication technologies (ICT) to facilitate the freedom of information request process. The data was collected using an open-source web interface that allowed users to submit an OPRA request to public authorities, with responses stored in a database and made available via the internet. After their request received a response, users were asked to answer a single survey question describing the status of their request, with their answer used to classify the request. Descriptive statistics, tables and frequencies were produced for the dataset and are included in this article. These data will assist state policymakers and other interested parties with assessing trends in OPRA requests across multiple types of public authorities & geographic regions. These data can inform more efficient government records management procedures, foster civic engagement by increasing government transparency and can inform the development of possible reforms to the OPRA law by showing trends in requests & responses that can be used to evaluate the law's implementation throughout the state.Peer reviewe
Gravity based foundations for offshore wind turbines: Cyclic loading and liquefaction
No full textCivil Engineering and GeosciencesHydraulic Engineerin
Correlating CPT data with stiffness parameters of sand in FEM
No full textMaking foundation designs is one of the major tasks of a geotechnical engineer. Toachieve such a design, knowledge of the soil stiffness is required. Information about the soil stiffness can be obtained by either laboratory tests or in situ tests. Laboratory testing is time consuming, costly and sample disturbance is inevitable. In situ tests are done directly on the soil encountered on the site and therefore are a good representation of the in situ soil state. CPT's are the most performed in situ tests in geotechnical engineering. CPT's are used to evaluate the subsurface based on the mechanical response translated to cone resistance and sleeve friction. Therefore it is desirable to find a correlation between soil stiffness and CPT results. A lot of research has been done to correlate CPT results, such as the cone resistance, with the stiffness of sand. It has been found that these correlations are highly variable and site specific. State parameters as consolidation state have a high influence on the soil stiffness but are difficult to evaluate from CPT results only. In this thesis the correlation between cone resistance and stiffness parameters for sand is investigated based on a series of Zone Load Tests done at a site in Kuwait. In a Zone Load Test a footing is loaded in steps and the settlement of the footing is measured. First an analytical settlement analysis is done with existing methodologies which use correlation between cone resistance and soil stiffness. The predicted settlements according to these methods are compared with settlements measured in the field. Afterwards, a new site specific correlation between cone resistance and soil stiffness is proposed using regression analysis. A verification of the new proposed correlation is done with the finite element program PLAXIS 2D. The numerical calculations were done with the Hardening Soil model using an axisymmetric approach. Multiple Zone Load Tests are simulated with PLAXIS 2D where the input parameters of the Hardening soil model are obtained from the proposed correlation. The numerical calculated settlement of the footing are in agreement with the measurements in the field and therefore it can be concluded that the correlation found for this site is valid. The general application of the proposed correlation is not confirmed. The research done in this thesis is related to direct settlement. Time dependent behaviour is excluded but could be of significant influence. Carbonate sands, as encountered at the site, are sensitive for particle crushing. Particle crushing can lead to creep effects and therefore it is advised to perform Plate Load Tests to get better insight in the creep behaviour in the sand fill.Civil Engineering and GeosciencesGeoscience & Engineerin
The Social Construction of the Child Sex Offender Explored by Narrative
No full textThe notion of "child sex offender" provokes aversion, but it may be that it is a social construction. We suggest that a Dominant narrative, in which child sex offenders are constructed as irredeemable, persists, despite the emergence of assumption challenging Alternative narratives. A story completion method was used to elicit themes of Dominant or Alternative narratives, theory-led thematic analysis was used to identify them. The use and analysis of narrative and free-form stories are well established in social research, but remain a novel concept in the study of offenders. The results support the persistence of the Dominant narrative with two notable exceptions. Conclusions centre on utility of the narrative method to examine offender constructions, and the pervasiveness of Dominant narratives. Key Words: Dominant and Alternative Narrative, Social Construction, Child Sex Offenders, and Thematic Analysi
Impact of scour on lateral resistance of wind turbine monopiles: An experimental study
No full textThe majority of offshore wind structures are supported on large-diameter, rigid monopile foundations. These piles may be subjected to scour due to the waves and currents that causes a loss of soil support and consequently decreases the pile capacity and system stiffness. The results of numerical models suggest that the shape of the scour hole affects the magnitude of pile capacity loss; however, there is a dearth of experimental test data that quantify this effect. This paper presents a series of centrifuge model tests on an instrumented model pile that investigates the effects of scour-hole geometry on the response of a laterally loaded pile embedded in sand. The pile instrumentation allowed load–displacement and p–y (soil reaction – displacement) curves to be derived. Three scour geometries (global, local wide, and local narrow) and three scour depths (1D, 1.5D, and 2D; where D is pile diameter) were modelled. For all three scour types, pile moment capacity decreased almost linearly with increase of scour depth. Simple empirical relations were proposed to evaluate the detrimental influence of scour on the pile moment capacity. A new method has been developed to allow designers to quantify the effect of scour-hole shape and severity of scour on the pile response.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Geo-engineerin
Undrained Bearing Capacity of Misaligned Suction Anchors: A Comparative Study on Different Numerical Approaches
No full textThe constantly increasing demand of the world for energy has led to a remarkable advancement in the offshore geotechnical engineering field that is closely related to the oil and gas production. In this industry, floating production facilities are connected with the seabed through mooring lines that are attached to anchor foundations. In this context, suction anchors have been increasingly installed to ensure good mechanical performance under variable operational loads. Therefore, they should be able to withstand the horizontal, vertical and torsional (HVT) loads stemming from the inclined loading imposed by the mooring chains. The undesired torsion is induced in the problem when the anchor is not perfectly aligned with the floating facility due to imperfections during installation. This work constitutes a comparative study between three distinctive numerical approaches that revolve around the undrained capacity of misaligned suction anchors founded in normally consolidated clay. Its main aim is to unravel the strengths and weaknesses of the well established methods of analysis used nowadays. The effectiveness of the two current adopted methods is shown with reference to a benchmark study that involves a thorough 3D finite element investigation on the impact of misalignment on the capacity of suction anchors following a total stress analysis (TSA) within Plaxis 3D. Even though this type of analysis (TSA) is widely employed nowadays, it is considered as a rough approximation of the actual soil behaviour under undrained conditions. This statement acted as an incentive to conduct an effective stress analysis (ESA) of the same problem. For this purpose, different calibrations of an advanced Cam - Clay type constitutive model (the Soft Soil model) were realised to capture the soil conditions of the benchmark study, which embraced a simplified Tresca failure criterion. Additionally, a simpler 2D numerical approach of the same problem was realised with the use of SPCalc, which is a special purpose tool that accounts for 3D effects through the application of side shear and reduction factors. In this case, misorientation is modelled by the reduction of the soil - anchor interface resistance. Failure envelopes are derived for the two current approaches and compared for three different length-to-diameter anchor ratios (1.5, 3 and 6), and for misalignment angles in the range of 0° to 10°. The outcomes of this study give a better insight into the practical implications of certain modelling assumptions. In particular, it is shown that the influence of misalignment on the undrained HV capacity may be in fact non-negligible, while the expected conservatism arising from simplified 2D analysis is quantitatively pointed out. Even though ESA is thought to enhance the mechanical soundness of undrained modelling, it creates additional difficulties in terms of soil parameter calibration. Therefore, the close relationship between HVT failure envelopes and the modelling of clay strength in the effective stress framework is critically discussed with respect to the preliminary results of the benchmark study.Civil Engineering and GeosciencesGeoscience & EngineeringGeo-Engineerin
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