In the analysis of piles supporting offshore structures, the key element in predicting the response to lateral loads is the determination of the appropriate lateral load - deformation relationships (p-y curves) for the soil. The present practice of constructing p-y curves is based on the results of lateral load tests on instumented piles and strength-deformation characteristics of the soil. (Matlock,1970; Reese et al, 1975; and API RP 2A, 1978) A study was undertaken to compare the results from lateral load tests on piles up to 59 inches in diameter driven in soft to medium clays to that predicted using the above ways of constructing p-y curves. In general, it was found that the predicted pile deflections were significantly greater than the observed deflections. Also the maximum bending moments were underestimated. Two factors were identified as sources of the differences; The first was the assumed linear dependence of the soil-deformation characteristics on pile diameter. The second was the lateral soil resistance at shallow depths was greater than those given by the empirical methods. Based on the study results, modifications are suggested to the present methods of constructing p-y curves. INTRODUCTION P-y curves are generally used to characterize the lateral soil resistance-deformation relationship for piles supporting offshore structures. These curves are related to the strength-deformation characteristics of the soil as obtained from conventional soil tests. The methods of constructing p-y curves for clays are empirically derived from the results of lateral load tests on instrumented piles. The use of empirical methods for design purposes is justifiable when the design conditions approximate those upon which the method is based. One of the important considerations in using empirical methods in geotechnical engineering is the scale effect. Ideally the size of the test element should be the same as the actual element. However, in most cases, it is impractical to perform a full scale test. The methods presently used for constructing p-y curves for clays were based on piles having diameters ranging from 6 to 24 inches. With the trend of installing platforms in deeper waters and more hostile enviroments, piles with diameters ranging from 5 to 8 feet are common. An extreme example is a number of 15-ft diameter piles driven in the Scheldt River delta to support a cable way. (Lubking, 1977) Piles of these diameters are much larger than those upon which the empirical methods are based. Lateral load tests on instrumented piles comparable to those presently used offshore have been published. In addition, other researchers have presented results which suggest ways to account for scale effects. This paper compares the test results to those predicted using the present methods of constructing p-y curves and suggests some modifications.
Purpose The purpose of this paper is to identify whether personality traits can help explain the outcomes that arise in bargaining outcomes. Design/methodology/approach Experiments with subjects playing the alternating-offers bargaining game are considered. Both full information and asymmetric information treatments are considered. Subjects also complete standardized Myers-Briggs Type Indicator assessments. Findings Personality type measurements are shown to help explain the opening offers, rejections, and resulting wealth in the negotiations. It is shown that interactions between the personality dimensions are important and that the interaction between personality and information play a key role in bargaining outcomes. Research limitations/implications The research utilizes laboratory experiments to generate data. This expands our understanding of individual-level behavior, but suffers from the limitation of not replicating realistic bargaining situations. Practical implications The work should serve as a guide to organizations to identify traits of effective negotiators. Social implications Bargaining is a central economic activity. Being able to identify the root of differences in outcomes from negotiations should be able to inform institutional design issues. Originality/value Little work has been done connecting the rich literature in social psychology and management on personality to economic outcomes. The research on bargaining neglects to incorporate individual-level traits into the process. This research begins to bridge this gap and informs both bargaining theory as well as emphasizes on the importance of personality in application.
The increase in use of variable frequency drives (VFDs) in oilfield facilities, especially for some offshore platforms, often leads to a significant percent of VFDs in total load demand. The VFDs provide many advantages for facility operation, but also produce harmonic contents to electrical power systems. Subsea cables are widely used in offshore power distribution systems. There are two typical applications for subsea cables: 1) transmitting power from the power generation to loads on remote platforms (involving line-side harmonics of a VFD); 2) transmitting power from the output of a VFD to remote electrical submersible pump (ESP) systems (involving load-side harmonics of a VFD). The combination of VFDs and subsea cables in power systems could introduce harmonic resonance, which, if not properly mitigated, amplify certain harmonics and cause significant damage to the electrical equipment in the facilities. An investigation was conducted for the two typical applications in offshore oilfield facilities considering harmonic resonance conditions. The first application involved parallel harmonic resonance and line harmonics, which will amplify harmonic currents. The second application involved harmonic resonance and load harmonics, which will amplify harmonic voltages. Computer simulation software programs were used to develop solutions using line-side and load-side harmonic filters to mitigate harmonics and attenuate resonance; these solutions were verified to be effective in case studies
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