Littérature scientifique sur le sujet « Push-over tests »
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Articles de revues sur le sujet "Push-over tests"
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Lin, S. S., C. H. Lai, C. H. Chen et T. S. Ueng. « Derivation of Cyclic p-y Curves From Instrumented Dynamic Lateral Load Tests ». Journal of Mechanics 26, no 2 (juin 2010) : 123–33. http://dx.doi.org/10.1017/s1727719100002987.
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AbstractIn this paper, an efficient method is proposed to derive cyclic p-y curves from either push-over or shaking table test results. The Fourier series function, satisfying the boundary conditions of a pile, is used to represent deflection behavior of the pile-soil system at each instant of time during loading interval. In order to obtain soil reaction along the pile shaft, convergence of the series after differentiation is guaranteed by applying the Cesaro sum technique. Results of four push-over tests and two other shaking table test results, conducted at the National Center for Research on Earthquake Engineering in Taiwan, are then used to verify the feasibility of the proposed method.
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Zhang, X., J. A. Knappett, A. K. Leung, M. O. Ciantia, T. Liang et F. Danjon. « Small-scale modelling of root-soil interaction of trees under lateral loads ». Plant and Soil 456, no 1-2 (18 septembre 2020) : 289–305. http://dx.doi.org/10.1007/s11104-020-04636-8.
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Abstract Aim (1) To understand the tree root-soil interaction under lateral and moment loading using a physical modelling technique; (2) To detect the possible factors (e.g. root architecture, water condition, and stress level) influencing a tree’s push-over behaviour; (3) To identify suitable scaling laws to use in physical modelling. Methods Two 1:20 scaled root models with different architectures (namely, deep and narrow, and shallow and wide) were reconstructed and 3D printed based on the field-surveyed root architecture data. Push-over tests were performed both in elevated-gravity (centrifuge 20-g) and normal-gravity (1-g) conditions. Results The shallow and wide model showed higher anchorage strength than the deep and narrow model. Regardless of the root architecture, the root anchorage strength measured from dry soil was higher than that from saturated soil. However, once the effective stress was the same, regardless of water conditions, the root anchorage strength would be the same. Conclusions The presence of water decreasing the soil effective stress and key lateral roots extending along the wind direction play a significant role on a tree’s push-over resistance. Centrifuge tests showed comparable results to the field pull-over measurements while 1-g model tests overestimated the root-soil interaction, which could be corrected for soil strength by using modified scaling laws.
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Robinson, Hugh. « Multiple stud shear connections in deep ribbed metal deck ». Canadian Journal of Civil Engineering 15, no 4 (1 août 1988) : 553–69. http://dx.doi.org/10.1139/l88-076.
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This paper summarizes the results of push-out tests conducted on 17 different types of shear connections simulating three distinct components of a composite floor system: (1) an interior beam (perpendicular metal deck), (2) a spandrel beam (perpendicular metal deck), and (3) a girder (parallel metal deck). Each push-out specimen had a layer of 152 × 152 WM9.1 × WM9.1 welded wire mesh at mid-depth of each concrete slab.Two composite beams, each with ribbed shear connections typical of those in two of the types of push-out specimens representing ribbed shear connections in interior composite beams with ribbed metal deck, were tested with third-point loads over a simply supported span. Using the average ultimate shear strengths of the push-out specimens having the same configurations as the ribbed shear connections in the composite beam tests to calculate the ultimate flexural capacities of the composite beams resulted in a very close estimate of the measured ultimate flexural capacities of the composite beams. The average measured static yield strengths of the flanges and webs of the wide-flange sections used in the composite beam tests were included in the calculations of the ultimate flexural capacities of the composite beams. Key words: composite, push-out, ultimate shear, shear stud, ribbed metal deck, deep rib.
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Nezamian, Abolghasem, Riadh Al-Mahaidi et Paul Grundy. « Bond strength of concrete plugs embedded in tubular steel piles under cyclic loading ». Canadian Journal of Civil Engineering 33, no 2 (1 février 2006) : 111–25. http://dx.doi.org/10.1139/l05-091.
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Investigation of the load transfer of concrete plugs to tubular steel piles subjected to tension and compression and cyclic loading has been conducted at Monash University over the past 3 years. The work presented in this paper reports on the results of the combination of pull-out, push-out, and cyclic loading tests carried out on 15 steel tube specimens filled partially with reinforced concrete with variable lengths of embedment. The pull-out force was applied through steel reinforcing bars embedded in the concrete plug, and push-out forces were applied through a thick top circular plate on the top of the concrete plug. Test results included the cyclic loading, ultimate pull-out and push-out forces, slip of concrete plugs, and longitudinal and hoop strains along the piles for some specimens. The tests clearly showed that average bond strength significantly exceeds expectations and is higher than the results of previous investigations using plugs without reinforcement. The test results also indicated that cyclic loading tests reduced the bond strength due to the accumulation of damage to the plug–pile interface. The push-out and pull-out tests conducted under symmetric cyclic loading demonstrated that slip between the concrete plug and the steel tube increased with repeated loading, and the rate of slip growth increased with an increase in the peak load.Key words: tubular steel pile, reinforced concrete plug, bond, cyclic loading.
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Speranza, Michael J. A., Tim J. Gabbett, David A. Greene, Rich D. Johnston, Andrew D. Townshend et Brett O’Farrell. « An Alternative Test of Tackling Ability in Rugby League Players ». International Journal of Sports Physiology and Performance 13, no 3 (1 mars 2018) : 347–52. http://dx.doi.org/10.1123/ijspp.2016-0701.
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This study investigated the relationship between 2 tests of tackling ability, muscle strength, and power in semiprofessional rugby league players. Thirty-one players, 19 first-grade and 12 second-grade, underwent tests of muscle strength (1-repetition-maximum bench press, chin-up, and squat) and power (plyometric push-up and countermovement jump). Tackling ability was assessed via video analysis of under-and over-the-ball tackle drills. The first-grade players had significantly greater scores in both the under-the-ball (P = .03, effect size [ES] = 0.84, 95% CI 0.07–1.50) and over-the-ball tackling-ability tests (P < .001, ES =1.86, 95% CI 0.83–2.52) than the second-grade players. A large, significant relationship was found between under- and over-the-ball tackling ability (r = .55, 95% CI .24–.76, P = .001). Lower-body strength (r = .37, 95% CI .02–.64, P = .04) was moderately associated with under-the-ball tackling ability, whereas over-the-ball tackling ability was moderately associated with plyometric push-up performance (r = .39, 95% CI .04–.65, P = .03). This study found that over-the-ball tackling ability was significantly associated with under-the-ball tackling in semiprofessional rugby league players. Furthermore, it was found that, compared with the second-grade players, the first-grade players had superior tackle ability in both tackle drills. In this study it was observed that plyometric push-up peak power was significantly related to over-the-ball tackling ability and absolute lower-body strength was associated with under-the-ball tackling ability. These findings provide skill coaches and strength and conditioning staff a greater understanding of elements that contribute to effective tackling ability.
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Lockie, Robert G., Robin M. Orr et J. Jay Dawes. « Justified Concerns ? An Exploration of the Leg Tuck in a Tactical Population ». International Journal of Environmental Research and Public Health 19, no 21 (26 octobre 2022) : 13918. http://dx.doi.org/10.3390/ijerph192113918.
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The leg tuck was replaced by the plank in the Army Combat Fitness Test, in part because it was felt it discriminated against women. There is limited leg tuck research, including between-sex comparisons and relationships with other fitness tests. This study investigated the leg tuck in a firefighter trainee population (274 males, 31 females). Archival fitness test data included: Illinois agility test (IAT); push-ups; pull-ups; leg tucks; multistage fitness test; 4.54 kg backwards overhead medicine ball throw (BOMBT); 10-repetition maximum deadlift; and 18 kg kettlebell farmer’s carry over a 91.44 m course. Independent samples t-tests (p < 0.05) and effect sizes (d) compared the sexes. Partial correlations and stepwise regression (controlling for sex; p < 0.05) calculated relationships between the leg tuck with the other tests. Male trainees outperformed females in all tests (p ≤ 0.003). The largest difference was for the BOMBT (d = 2.59) not the leg tuck (d = 1.28). The strongest leg tuck relationships were with pull-ups (r = 0.790) and push-ups (r = 0.553). Sex, pull-ups, and push-ups predicted the leg tuck (r2 = 0.674). Approximately 80% of the females could complete one leg tuck, although female personnel may require specific strength and power training. Pulling strength may be a determining factor in leg tuck performance, which is likely not indicated by the plank.
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Zhong, Wei, Shuai Zhang et Na He. « An Experimental Study on the Dynamic Evolution Characteristics of Soil Arching and the Rational Spacing of Anti-Slide Piles ». Sustainability 14, no 14 (13 juillet 2022) : 8566. http://dx.doi.org/10.3390/su14148566.
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In order to analyse the dynamic evolution characteristics of soil arching during sliding processes, we conducted a series of model push-pile and direct shear tests. The tests’ results were used to design a relative displacement monitoring system and to introduce two dimensionless parameters (the push–compaction ratio (e) and the different degrees of push–compaction (t)) to investigate the degree of uneven soil deformation during the sliding processes. This innovative method was used to analyse the rational spacing between adjacent anti-slide piles. The results revealed that there was a push-to-compaction effect in sliding soil during the sliding process. Firstly, in terms of space, the gradual transfer characteristics of the landslide thrust and push-to-compaction effect, rather than a uniform deformation over the entire area, were revealed. In terms of time, the results demonstrated a law for the variation in push-to-compaction ratios: The expansion of e occurred earlier in the rear sliding body than in the front e, while the growth rate of front e was faster than that of e in the rear sliding body. The dynamic evolution process was divided into three stages: an elastic formation stage, a plastic development stage, and a failure stage. Secondly, during the sliding process, the shear strength parameters of the sliding soil did not have constant values but underwent a dynamic process of strengthening, and cohesion responded more efficiently than friction. Finally, the degree of mobilisation of the anti-sliding effect of the sliding soil can be used as a new means of quantitative analysis for rational spacing. The results indicated that the rational spacing between adjacent piles should be five times the width of the pile.
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Zhang, Yongtao, Hehui Zheng, Minghao Tang et Zhiqi He. « An Enhanced UHPC-Grout Shear Connection for Steel-Concrete Composite Bridges with Precast Decks ». Advances in Civil Engineering 2021 (25 mai 2021) : 1–15. http://dx.doi.org/10.1155/2021/5595174.
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This article develops an enhanced UHPC-grout shear connection for steel-concrete composite bridges with precast decks. The primary improvement is the use of ultra-high performance concrete (UHPC) as the connection grout. To validate the constructability and the mechanical performance of the new connection, two series of experimental tests (including grouting tests and push-out tests) were conducted. Results from the grouting tests show that both the pressure grouting method and the self-levelling grouting method are applicable to inject the UHPC grout into the channel void of the connection. Results from the push-out tests indicate that the advanced properties of UHPC allow for a significant improvement of the shear resistance of the adhesive connection over traditional cementitious grouts. The ultimate shear capacity of the adhesive connection is controlled by the interface shear strength between the embossed steel and the UHPC grout, with a cohesion value of approximately 5.87 MPa. Meanwhile, the residual frictional resistance can be taken as approximately one-half of the ultimate resistance. The results of the finite-element analysis show that the trilinear model is reasonable to simulate the shear-slip laws of the embossed steel-grout interface and the rough concrete-grout interface.
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Kanyilmaz, Alper, Giovanni Brambilla, Gian Paolo Chiarelli et Carlo Andrea Castiglioni. « Assessment of the seismic behaviour of braced steel storage racking systems by means of full scale push over tests ». Thin-Walled Structures 107 (octobre 2016) : 138–55. http://dx.doi.org/10.1016/j.tws.2016.06.004.
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Li, Yeou-Fong, Jian-Yu Lai et Chung-Cheng Yu. « The Push-Over Test and Numerical Analysis Study on the Mechanical Behavior of the GFRP Frame for Sustainable Prefabricated Houses ». Sustainability 11, no 23 (28 novembre 2019) : 6753. http://dx.doi.org/10.3390/su11236753.
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The glass fiber reinforced plastics (GFRP) composite material is a low carbon emission, low life cycle cost, and sustainable material. In this paper, the structural behavior of the lateral force resistant performance of GFRP composite material frames with steel joints was presented, and the energy dissipation and failure modes of the GFRP frames were discussed. A total of six GFRP frames, including single-span and double-span frames with and without diagonal bracing members, were tested by pushover tests to obtain the lateral load-displacement relationships of the GFRP frames. The force-displacement relationship and the energy dissipation of the GFRP frames were examined in the pushover test. In addition, the numerical analysis was performed to obtain the lateral load-displacement relationships of the GFRP frames under pushover tests. When the numerical analysis results and the experimental results were compared, the absolute average errors of the maximum loads were less than 4%, and the lateral load-displacement relationships were close to each other. The numerical analysis results can predict the experimental force-displacement relationships of the GFRP frames.
Thèses sur le sujet "Push-over tests"
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Huang, De-Zhi, et 黃德治. « Analysis and simulation of push over test for an existing Reinforced Concrete Building ». Thesis, 2007. http://ndltd.ncl.edu.tw/handle/90288428673223946892.
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碩士中原大學
土木工程研究所
95
Analysis of the seismic assessment for the building result that relates to plastic hinge property for every member. But the plastic hinge property with studied the theory in the past, no studies have compared to existing building test data. So since the 94th year of the Republic of China, the National Center for Research on Earthguake Engineering carry out a series of static push over tests for existing building, in order to get result of the correspond to earthquake damage of reality. This text use of various kinds of theories, calculate the intensity and plastic hinge property of the beam, colum and brick wall. And used to analysis of nolinear static push over in SAP2000 to simulation of the behavior and way of destroying in earthquake of the building. Then compare with results of the push over test for existing building in order to look for a good simulation method.
Livres sur le sujet "Push-over tests"
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Camper, Martin. The Interpretive Stases. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780190677121.003.0001.
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Chapter 1 introduces the interpretive stases as a neglected rhetorical method that could be productively employed by scholars to analyze debates over the meaning of texts in virtually any sphere. The chapter begins with a debate over one of the leaked 2009 “climategate” emails, which seriously damaged the credibility of climatologists, to illustrate the far-reaching consequences of interpretive arguments. A brief sketch is provided of the interpretive stases’ history, from their origins in ancient Greco-Roman legal theory to when they were dropped from rhetorical manuals in the seventeenth century. The chapter explores the relationship between rhetoric and hermeneutics—philosophical, literary, legal, and religious—and argues that no school of hermeneutics offers a general method for analyzing the argumentative push and pull involved in the interpretation of any text. The final part of the chapter outlines the six interpretive stases and discusses how they frame textual interpretation in terms of argument and persuasion.
Chapitres de livres sur le sujet "Push-over tests"
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Hoogeveen, Troy, et Joe White. « A Macro Modelling Blind Prediction of a Cyclic Push-Over Test on a Full Scale Masonry House ». Dans Seismic Hazard and Risk Assessment, 505–17. Cham : Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-74724-8_34.
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Jackson, Rowan, Steven Hartman, Benjamin Trump, Carole Crumley, Thomas McGovern, Igor Linkov et AEJ Ogilvie. « Disjunctures of Practice and the Problems of Collapse ». Dans Perspectives on Public Policy in Societal-Environmental Crises, 75–108. Cham : Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-94137-6_7.
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AbstractThis chapter asks what insights long-term historical information from before the Great Acceleration and Anthropocene might offer to policy and practice in the twenty-first century. Conventional sustainability research usually focuses on shallower time horizons that could miss insightful environmental and social processes evolving over centuries to millennia. Although we push for increased engagement with historical researchers, parallels between pre-modern and contemporary environmental and societal challenges need to be treated with caution. So-called cases of societal collapse—often associated with environmental calamities—provide limited or at best flawed parallels with challenges faced today. The pitfalls of reductionism and determinism that often attend collapse discourse account for social agency and complexity in incomplete and unconvincing ways. Instead, we argue that historical evidence should serve as context to environmental problems faced today, as antecedents of the accelerated environmental change of later modernity rather than as direct analogies. Historical antecedents can be understood, to an extent, as previous experiments against which to test and improve theory or to structure possibilistic scenarios that help anticipate unexpected social and environmental challenges. In concluding, we suggest that researcher in historical sciences and the humanities require resources, space and incentives to explore sticky questions of uncertainty, risk, and vulnerability to environmental change together with global change researchers, policymakers, and environmental practitioners.
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Horvath, Joachim, Karina Meyer et Alex Wiegmann. « Intuitive Expertise and Irrelevant Options ». Dans Oxford Studies in Experimental Philosophy Volume 3, 275–310. Oxford University Press, 2020. http://dx.doi.org/10.1093/oso/9780198852407.003.0012.
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In the ‘push-dilemma,’ a train is about to run over several people and can only be stopped by pushing a heavy person onto the tracks. Most lay people and moral philosophers consider the ‘push-option,’ i.e., pushing the heavy person, as morally wrong. Peter Unger (1992, 1996) suggested that adding irrelevant options to the push-dilemma would overturn this intuition. This chapter tests Unger’s claim in an experiment with both lay people and expert moral philosophers. This allowed an investigation of the ‘expertise defense,’ which various philosophers have suggested as an answer to ‘experimental restrictionists,’ who argue that experimental philosophy undermines the trustworthiness of intuitions about hypothetical cases. Overall, the chapter finds that adding irrelevant options increases the ratings for the push-option. Moreover, the intuitions of expert moral philosophers are no less susceptible to the presence of irrelevant options than lay people’s intuitions. The chapter discusses how these findings bear on the expertise defense.
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Finn, Chester E., et Andrew E. Scanlan. « Does Platinum Bend ? Standards under Stress ». Dans Learning in the Fast Lane, 155–69. Princeton University Press, 2019. http://dx.doi.org/10.23943/princeton/9780691178721.003.0010.
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This chapter argues that the greatest asset of the Advanced Placement (AP) program over nearly seven decades has been its capacity to set and maintain lofty academic standards for high school students and to sustain those standards during times when many forces push to relax them. That is an extraordinary accomplishment, considering all that has happened in American education during this period. Academic standards of various kinds have become a big deal, a growth industry, and an endless source of controversy, especially when accompanied—as they usually are—by student tests. Advanced Placement's nongovernmental character is rare in the world of education standards, at least since 1989. That was the year that state governors and President George H. W. Bush convened in Charlottesville, Virginia, and emerged from their “summit” with an ambitious set of national education goals for the year 2000. Congress created the National Council on Education Standards and Testing to “explore the desirability and feasibility of establishing national education standards and a method to assess their attainment” and a National Education Goals Panel to monitor and report on how the country was doing in pursuit of the summit targets. Many complications, modifications, and pushbacks followed. Ultimately, the entire quarter-century sequence left many hostile both to governmental micromanagement of schooling and, especially, to anything that smacked of government-prescribed standards, curricula, and tests. With just a few exceptions and caveats, the AP program has been immune to this suspicion, rancor, and resistance.
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Marinari, Maddalena. « The Battle Begins ». Dans Unwanted, 14–42. University of North Carolina Press, 2020. http://dx.doi.org/10.5149/northcarolina/9781469652931.003.0002.
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The first chapter examines Italian and Jewish immigrants’ efforts to oppose proposed restrictions on new immigrants from eastern and southern Europe from the passage of the 1882 Immigration Act to the adoption of a literacy test in 1917. During this critical period in the rise of the antirestrictionist movement, both groups created national advocacy organizations (American Jewish Committee and the Order Sons of Italy) to negotiate with legislators in hopes of achieving more political influence. These organizations successfully opposed the passage of a literacy test for arriving immigrants older than 16 until World War I, when organizations like the Immigration Restriction League successfully used the war to mobilize labor unions, reformers, regular Americans, and politicians from the South eager to preserve their political influence to push for the test, which Congress passed over President Wilson’s veto. War and immigration emerge as linked processes in U.S. history. Amid rampant anti-immigrant rhetoric and violence during WWI, the debate over immigration policy pitted advocates for qualitative restriction against those who advocated for quantitative restriction as the best approach to curtail immigration from eastern and southern Europe. Supporters of the literacy test won a temporary battle.
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Chernov, Yury. « Data Quality Measurement Based on Domain-Specific Information ». Dans Data Integrity and Data Governance [Working Title]. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.106939.
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Over the past decades, the topic of data quality became extremely important in various application fields. Originally developed for data warehouses, it received a strong push with the big data concept and artificial intelligence systems. In the presented chapter, we are looking at traditional data quality dimensions, which mainly have a more technical nature. However, we concentrate mostly on the idea of defining a single data quality determinant, which does not substitute the dimensions but allows us to look at the data quality from the point of view of users and particular applications. We consider this approach, which is known as a fit-to-use indicator, in two domains. The first one is the test data for complicated multi-component software systems on the example of a stock exchange. The second domain is scientific research on the example of validation of handwriting psychology. We demonstrate how the fit-to-use determinant of data quality can be defined and formalized and what benefit to the improvement of data quality it can give.
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Zellinger, Elissa. « The Poetess and the Politics of Profession ». Dans Lyrical Strains, 35–61. University of North Carolina Press, 2020. http://dx.doi.org/10.5149/northcarolina/9781469659817.003.0002.
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This chapter argues that women's writing, specifically poetry in the "Poetess" genre, exposes the tensions that wrack both the ideal liberal and lyric selves. The self-made, autonomous liberal subject was built on a permeable public/private distinction; public circulation confirmed one's circumscribed, and therefore sovereign, interiority. With its expression of private feelings, Poetess poetry was thought to demonstrate the opposite—namely, women's inability to exert liberal self-possession in public and, by extension, their dependent social status and the necessity of confining them to the domestic sphere. In order to illustrate how the literary public sphere enforced these conventions over time, this chapter compares popular texts that rehearse the expectation that women poets were not professional writers but amateurs: they could not help but profess sincere feminine emotion in their poems. In so doing, authors writing Poetess poems could turn amateurism into a kind of public "profession" (both line of work and declaration), and thereby push against the boundaries of belonging that liberalism had set. The chapter explores this process with the example of Frances Sargent Osgood, whose poems specifically about the profession of the Poetess self-consciously expose a feminized interior in public.
Actes de conférences sur le sujet "Push-over tests"
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Chen, Hung-Chi, Walter W. Chen et Che-Hao Chang. « Novel in situ method for fast determination of bridge pier displacements during push-over tests ». Dans International Symposium on Lidar and Radar Mapping Technologies. SPIE, 2011. http://dx.doi.org/10.1117/12.912834.
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Bienen, Britta, Mark J. Cassidy et Christophe Gaudin. « Push-Over Response of a Jack-Up on Sand of Different Relative Densities ». Dans ASME 2009 28th International Conference on Ocean, Offshore and Arctic Engineering. ASMEDC, 2009. http://dx.doi.org/10.1115/omae2009-79236.
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On location offshore, jack-up structures are subject to environmental loading from wind, waves and current in addition to self-weight. Over the operational period of the jack-up, the environmental loading on a given site may not be unidirectional along the jack-up’s ‘axis of symmetry’ but may act from different directions and/or be non-collinear (i.e. wind acting from a different direction than waves and current), resulting in complex load paths at the spudcan footings. This paper discusses load paths obtained from experiments on a scaled model jack-up for two different horizontal loading directions and illustrate the implications of spudcan load paths for the overall response of a jack-up to failure. Similar tests were performed at two different relative sand densities, allowing the influence of relative density on jack-up behavior to be investigated. Similitude to the prototype was achieved by conducting the experiments in a geotechnical centrifuge at 200g. The paper concludes with numerical predictions of the experimentally measured response, using a macro-element to model the soil-spudcan interaction coupled to a structural finite element program. The footing macro-element has been developed based on plasticity theory and single footing experiments, but its ability to predict the respective load paths of each of the spudcans in a multi-footing system is demonstrated here. The paper further provides the experimentally measured jack-up push-over capacity and numerical predictions in the context of recommendations of current guidelines. This highlights the requirement of nonlinear elasto-plastic modelling of the load-displacement behavior of the jack-up foundations in order to predict the overall response of the system.
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Pascual, Ana Maria, Ulrike Kuhlmann, Jakob Ruopp et L. Stempniewski. « Headed studs close to concrete edge under pull-out ». Dans 12th international conference on ‘Advances in Steel-Concrete Composite Structures’ - ASCCS 2018. Valencia : Universitat Politècnica València, 2018. http://dx.doi.org/10.4995/asccs2018.2018.7151.
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The capacity of the headed studs when they are close to the edge may be limited by the splitting forces in the concrete. In the Eurocode 4 Part 2 Annex C the shear capacity under this particular arrangement of the studs, which is directly dependent on the distance to the edge, is formulated. In addition, the geometrical restrictions to prevent the failure by pull-out of the studs are also given in clause C1 (2). These rules are based on push-out tests for the edge position where tension forces in the lying studs spread over the width of the specimen in this unfavorable way. Nonetheless, the current limits lead to extremely long studs and represent a severe restriction, and on the other hand, it is still an open question whether in real buildings or bridge girders the tension stresses that produce the pull-out appears in the same way as in the push out tests. In this paper the revision of these restrictions is presented together with a research for the alternative use of EN 1992-4 plus RFCS Project INFASO for the verification of the tension loads on the studs.
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Vlahos, G., M. J. Cassidy et B. Knowles. « A Comparative Assessment of the Use of Spudcans and Caissons as the Foundations of Jack-Up Structures ». Dans ASME 2005 24th International Conference on Offshore Mechanics and Arctic Engineering. ASMEDC, 2005. http://dx.doi.org/10.1115/omae2005-67090.
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More than ever before, operators are advancing mobile jack-up units into deeper waters and harsher environments. Constraining their use is the capacity of the shallow foundations (typically inverted conical spudcans) to withstand the larger wave, wind and current loads of these environments. The use of foundation skirts (or caissons) is often touted as an alternative, though today only a small percentage of jack-up units use caisson foundations. One restraining feature is limited understanding of their behaviour when compared to conventional spudcan. This paper addresses this by comparing the results of push-over experiments of a three-legged jack-up with similarly sized caisson and spudcan foundations. The tests were conducted on a 250:1 scale jack-up on an overconsolidated clay sample. With improved understanding of the overall response of a jack-up platform with caisson foundations, operators should have greater confidence to use these footings.
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San Andrés, Luis, Sean Den et Sung-Hwa Jeung. « On the Force Coefficients of a Flooded, Open Ends Short Length Squeeze Film Damper : From Theory to Practice (and Back) ». Dans ASME Turbo Expo 2017 : Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/gt2017-63152.
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Gas turbine aircraft engine manufacturers push for simple squeeze film damper (SFD) designs, short in length, yet able to provide enough damping to ameliorate rotor vibrations. SFDs employ orifices to feed lubricant directly into the film land or into a deep groove. The holes, acting as pressure sources (or sinks), both disrupt the film land continuity and reduce the generation of squeeze film dynamic pressure. Overly simple predictive formulations disregard the feedholes and deliver damping (C) and inertia (M) force coefficients not in agreement with experimental findings. Presently, to bridge the gap between simple theory and practice, the paper presents measurements of the dynamic forced response of an idealized SFD that disposes of the feedholes altogether. The short-length SFD, whose diameter D = 125 mm, has one end submerged (flooded) within a lubricant bath and the other end exposed to ambient. ISO VG 2 lubricant flows by gravity through the film land of length L = 25.4 mm and clearance c = 0.122 mm. From dynamic load tests over excitation frequency range 10–250 Hz, experimental damping coefficients (CXX, CYY) from the flooded damper agree well with predictions from the classical open ends model with a full film for small amplitude whirl motions (r/c << 1), centered and off-centered. Air ingestion inevitably occurs for large amplitude motions (r/c > 0.4) thus exacerbating the difference between predictions and tests results. For reference, identical tests were conducted with a practical SFD supplied with lubricant (Pin = 0.4 bar) via three orifice feedholes, 120° apart at the film land mid plane. A comparison of test results shows as expected, that for small amplitude (r/c ∼ 0.05) orbits, the flooded damper generates on average 30% more damping than the practical configuration as the latter’s feedholes distort the generation of pressure. For large amplitude motions (r/c > 0.4), however, the flooded damper provides slightly lesser damping and inertia coefficients than the SFD with feedholes whose pressurized lubricant delivery alleviates air ingestion in the film land. The often invoked open ends SFD classical model is not accurate for the practical engineered design of an apparently simple mechanical element.
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Wilk, Stephen. « Parameters Affecting Lateral Track Strength After Surfacing ». Dans 2022 Joint Rail Conference. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/jrc2022-78724.
Texte intégralRésumé :
Abstract Over the past two years, Transportation Technology Center, Inc. (TTCI) has been investigating how tie and ballast parameters affect lateral track strength after surfacing. This investigation included both a literature review of previous work in the United States and single tie push tests (STPTs) performed under a variety of tie and ballast conditions at the Facility for Accelerated Service Testing (FAST) in Pueblo, CO. Knowing which parameters affect lateral tie strength and comparing the influence of the various parameters can help in lateral stability risk-assessments in continuously welded rail (CWR) track. The results of both the literature review and the STPT testing showed that the parameters of post-surfacing tonnage accumulation (for ballast density), tie type, ballast shoulder width, ballast crib height, tamping lift height, and ballast particle characteristics all have a significant influence on the lateral tie strength of clean ballast. The results both emphasize the importance of considering multiple parameters when assessing track buckling risk and verifies the good practice of having both full ballast shoulders and crib heights for resisting lateral and longitudinal movements. TTCI plans to incorporate these parameters into mathematical models that predict the lateral tie strength based on measurable tie and ballast condition parameters, holistic track buckling prediction models, and risk-based rail neutral temperature (RNT) management recommendations.
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Tyrell, David, Karina Jacobsen, Eloy Martinez et A. Benjamin Perlman. « Train-to-Train Impact Test of Crash Energy Management Passenger Rail Equipment : Structural Results ». Dans ASME 2006 International Mechanical Engineering Congress and Exposition. ASMEDC, 2006. http://dx.doi.org/10.1115/imece2006-13597.
Texte intégralRésumé :
On March 23, 2006, a full-scale test was conducted on a passenger rail train retrofitted with newly developed cab end and non-cab end crush zone designs. This test was conducted as part of a larger testing program to establish the degree of enhanced performance of alternative design strategies for passenger rail crashworthiness. The alternative design strategy is referred to as crash energy management (CEM), where the collision energy is absorbed in defined unoccupied locations throughout the train in a controlled progressive manner. By controlling the deformations at critical locations the CEM train is able to protect against two dangerous modes of deformation: override and large-scale lateral buckling. The CEM train impacted a standing locomotive-led train of equal mass at 31 mph on tangent track. The interactions at the colliding in Interface and between coupled interfaces performed as expected. Crush was pushed back to subsequent crush zones and the moving passenger train remained in-line and upright on the tracks with minimal vertical and lateral motions. The added complexity associated with this test over previous full-scale tests of the CEM design was the need to control the interactions at the colliding interface. between the two very different engaging geometries. The cab end crush zone performed as intended because the locomotive coupler pushed underneath the cab car buffer beam, and the deformable anti-climber engaged the uneven geometry of the locomotive anti-climber and short hood. Space was preserved for the operator as the cab end crush zone collapsed. The coupled interfaces performed as predicted by the analysis and previous testing. The conventional interlocking anti-climbers engaged after the pushback couplers triggered and absorbed the prescribed amount of energy. Load was transferred through the integrated end frame, and progressive controlled collapsed was contained to the energy absorbers at the roof and floor level. The results of this full-scale test have clearly demonstrated the significant enhancement in safety for passengers and crew members involved in a push mode collision with a standing locomotive train.
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Vigneri, Valentino, Christoph Odenbreit et Matthias Braun. « Numerical evaluation of the plastic hinges developed in headed stud shear connectors in composite beams with profiled steel sheeting ». Dans 12th international conference on ‘Advances in Steel-Concrete Composite Structures’ - ASCCS 2018. Valencia : Universitat Politècnica València, 2018. http://dx.doi.org/10.4995/asccs2018.2018.7166.
Texte intégralRésumé :
For composite beams using novel steel sheeting, the current Eurocode 4 rules sometimes overestimate the load bearing capacity of the shear connector. This is due to the larger rib heights and the smaller rib widths in comparison with the old studies, which have been carried out to calibrate the current design equations. The RFCS Project “DISCCO” investigated this phenomena and the working group under mandate M515, CEN/TC250/SC4/SC4.T3 is enhancing this equation and working on a proposal to be taken over in the new version of Eurocode 4.The proposed new equation covers the failure behaviour of the shear connection more in detail. The test results show, that the failure consists in a combined concrete cone and stud in bending. Due to the geometry of novel steel sheeting, the load bearing capacity of the headed stud shear connector is no more limited by its shear capacity, but by its bending capacity.A 3D non-linear finite element model is developed and validated through the support of the DISCCO push-out tests. A good agreement between numerical and experimental results in terms of force-slip behaviour is achieved. Special attention of this work lies on the numerical evaluation of the number of plastic hinges ny: a stress-based procedure is presented and the results are compared to the equations presented for new Eurocode 4.The numerical simulations show that the upper plastic hinge moves up as the slip increases due to the progressive crushing of the concrete in the rib. From the parametric study, it turns out that ny is linearly proportional to the embedment depth. Compared to pre-punched hole decking, through-deck welding specimen activates less plastic hinges in the studs because of the higher stiffness provided at the base of the stud.
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McFarland, Andrew W., Jonathan S. Colton, Daniel Cox et Steven Y. Liang. « Manufacture of Microcantilever Sensors ». Dans ASME 2005 International Mechanical Engineering Congress and Exposition. ASMEDC, 2005. http://dx.doi.org/10.1115/imece2005-81379.
Texte intégralRésumé :
Mechanical micro machining is an emerging technology with many potential benefits and equally great challenges. The push to develop processes and tools capable of micro scale fabrication is a result of the widespread drive to reduce part and feature size. One important factor that contributes to the ability to machine at the microscale level is the overall size of the machine tool due to the effects of thermal, static, and dynamic stabilities. This paper explores the technical feasibility of miniaturized machine tools capable of fabricating features and parts on the micro scale in terms of depth of cut and part form accuracy. It develops a machine tool and examines its capabilities through benchmarking tests and the making of precision dies for the injection molding of microcantilever parts. The design and configuration of a miniaturized vertical machining center of overall dimension less than 300 mm on a side is presented and the component specifications discussed. The six axis machine has linear positioning resolution of 4 nm by 10 nm by 10 nm, with accuracy on the order of 0.3 μm, in the height, feed, and cross feed directions. The work volume as defined by the ranges of axes travel are 4 mm by 25 mm by 25 mm in the height, feed, and cross feed and 20 degrees in the rotational space. To quantify the performance capability of the miniaturized machine tool as a system, a series of evaluation tests were implemented based on linear and arch trajectories over a range of feed speed and depth of cut conditions. Test results suggest that micro level form accuracy and sub-micron level finish are generally achievable for parts with moderate curvature and gradient in the geometry under selected machining parameters and conditions. An injection mold was made of steel with this machine and plastic microcantilevers fabricated. Plastic microcantilevers are appropriate for sensing applications such as surface probe microscopy. The microcantilevers, made from polystyrene, were 464 to 755 μm long, 130 μm wide and only 6–9 μm thick. They showed very good uniformity, reproducibility, and appropriate mechanical response for use as sensors in surface force microscopy.
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Lehn, Patrick, Nils Hinzmann et Jörg Gattermann. « New Approach for Offshore Pile Decommissioning With Hydraulic Presses and Floating Panels ». Dans ASME 2020 39th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/omae2020-18784.
Texte intégralRésumé :
Abstract Renewable Energies become more and more important in industries and society all over the world. In Germany, offshore wind farms generated 49 % of the renewable energies in 2018. Monopiles are the preferred system for the foundation of offshore wind turbines in water depths up to 40 m. They are authorized by the competent authority for 25 years. When reaching the end of lifetime, the structure inclusive the foundation must be decommissioned. The decommissioning of monopiles will be challenging in the future and can lead to unexpected costs and risks for the owners. Removing the monopiles in it’s entirely ensures the opportunity to reuse the space for new offshore wind farms. The Institute of Geomechanics and Geotechnics of the Technische Universität Braunschweig (IGG-TUBS) obtained the funding for the research program on technical solutions with large-scale tests for decommissioning of offshore monopiles named DeCoMP. Several decommissioning methods such as vibratory extraction, internal dredging, external jet drilling, decommissioning with overpressure and the use of buoyancy force are investigated. The proposed paper will present technical opportunities and issues for extracting the pile with hydraulic presses in combination with a steel framework. Hydraulic presses brace the steel framework with the monopile. Further hydraulic presses, positioned at a certain distance to the pile on the framework, use the seabed as abutments to push out the monopile. In addition, results of a feasibility study to remove monopiles with floatation panels are presented in this paper. This method is based on floating panels, which are attached to the monopile above the mud line. These panels are inflated with air pressure to reach the required amount of buoyancy to overcome the pullout resistance. The decommissioning solutions are compared to point out possible combinations.
Rapports d'organisations sur le sujet "Push-over tests"
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SHEAR BEHAVIOR OF NOVEL DEMOUNTABLE BOLTED SHEAR CONNECTOR FOR PREFABRICATED COMPOSITE BEAM. The Hong Kong Institute of Steel Construction, décembre 2022. http://dx.doi.org/10.18057/ijasc.2022.18.4.2.
Texte intégralRésumé :
Bolted shear connectors offer alternatives to achieve steel-concrete composite action instead of conventional welded headed studs especially for prefabricated constructions and demountable composite structures. This paper firstly proposed a new type of demountable steel-concrete bolted shear connectors based on the double-nut friction-grip high strength bolted connector, which modify the upper nut into conical locking nut. This paper performed ten full scale push-out tests to study shear behaviors of the developed new type of connectors. Testing parameters included bolt configuration, strength, diameter of bolts and strength of infilled grout. Test results indicate that shear behaviors and slip capacity of the conventional bolted connectors are significantly improved when the bolted connector incorporating with conical locking nut. The influences of these studied parameters on shear behaviour of novel bolted shear connectors are revealed and discussed. The developed novel demountable connector exhibits an average 25% improvement in ultimate shear resistance over conventional bolted connectors. Moreover, the shear stiffness of the developed bolted connectors is about six times of the conventional bolted connector through eliminating the clearance between steel flange hole and bolt shank.