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Die Arbeit stellt ein umfangreiches Hilfsmittel beim Umgang mit alten Brückenkranstrukturen dar, um einen sicheren Kranbetrieb an der Grenze und beim Überschreiten der rechnerischen Lebensdauer zu gewährleisten. Sie konzentriert sich dabei auf Ermüdungsschäden in der primären Tragstruktur von Brückenkranen, da diese das größte Gefahrenpotential darstellen. Die Zielsetzung der Arbeit lässt sich im Kern mit der „Maximierung der Krannutzungsdauer bei minimalen Stillstandzeiten und sicherem Kranbetrieb“ beschreiben. Aufgrund der Komplexität von Ermüdungsrissen in Bezug auf deren Entstehung und auf den Umgang nach deren Auftreten wurde die Zielsetzung mit unterschiedlichen Lösungsansätzen verfolgt. Es wurden die drei Kernansätze – Lebensdauervorhersage, Strukturüberwachung und Struktursanierung bzw. -ertüchtigung verfolgt. Zur Reduzierung von Stillstandzeiten dient eine Lebensdauervorhersage, mithilfe welcher die verbleibende Zeit bis zum Eintreten einer Strukturschädigung abgeschätzt werden kann, was eine bedarfsorientierte und frühzeitige Strukturertüchtigung erlaubt und somit die prädiktive bzw. präventiv zustandsabhängige Instandsetzung ermöglicht. Eine Lebensdauervorhersage basiert auf Berechnungen der Ermüdungsfestigkeit, welche ertragbare Beanspruchbarkeiten und ertragene Beanspruchungen gegenüberstellen. Um die Qualität einer Lebensdauervorhersage erheblich zu verbessern, wurde ein Messverfahren entwickelt, welches die Erfassung der Kranbelastungsgrößen mit einem vergleichsweise geringen messtechnischen Aufwand erlaubt und an jedem Brückenkran nachgerüstet werden kann. Ein sicherer Kranbetrieb soll mit einer fortwährenden Strukturüberwachung kritischer Bereiche sichergestellt werden. Ermüdungsrisse in Kranstrukturen werden zumeist im Rahmen von turnusmäßig durchgeführten Sichtprüfungen oder häufig sogar zufällig festgestellt. Dies hat zur Folge, dass das Risswachstum größtenteils weit fortschreiten kann und die Struktur stark geschädigt wird oder es zum Bruch und somit zu schweren Havarien kommt. Zur Vermeidung derartiger Szenarien wurde ein Verfahren zur Erfassung von Ermüdungsrissen auf Basis der Veränderung der Materialdehnung während des Risswachstums entwickelt. Wie auch das Verfahren zur Erfassung der Belastungsgrößen zeichnet es sich durch einen geringen messtechnischen Aufwand und eine universelle Anwendbarkeit aus. Neben der qualitativen Erfassung von Ermüdungsrissen ermöglicht das Verfahren ebenfalls quantitative Aussagen in Form von Risslängen und -positionen. Durch den Abgleich mit bruchmechanischen Grenzwerten, welche im Rahmen von strukturmechanischen Simulationen ermittelt werden können, kann das Gefahrenpotenzial eines Ermüdungsrisses während des fortschreitenden Risswachstums bewertet werden. Eine Maximierung der Kranlebensdauer kann durch eine lokale Veränderung der Tragstruktur erreicht werden. Bei der Konstruktion vieler älterer Krane konnten keine strukturmechanischen Simulationen zur Bewertung kritischer Strukturdetails genutzt werden. Hierdurch kam es mitunter zur falschen Einschätzung von Kerben. Durch die nachträgliche Begutachtung bestehender Kranstrukturen mithilfe der Finiten-Elemente-Methode (FEM), können derart kritische Strukturbereiche identifiziert und darüber hinaus modifiziert werden. In der Arbeit werden verschiedene Kernansätze bei der beanspruchungsbezogenen Optimierung von Kranstrukturen extrahiert und dargestellt. Diese können entweder als Reaktion auf einen Schaden (Sanierung) oder als Prävention vor einem Schaden (Ertüchtigung) umgesetzt werden. Da die modifizierten Strukturbereiche i. d. R. erheblich von den in den Normen katalogisierten Strukturstellen abweichen, sollte im Vorfeld der Umsetzung einer Strukturmodifizierung eine versuchstechnische Validierung erfolgen. Hierfür wurde eine Prüfvorrichtung entwickelt, welche speziell für große Strukturbauteile geeignet ist und die Ermittlung beanspruchbarkeitsspezifischer Parameter für nicht katalogisierte Strukturbereiche von Brückenkranen ermöglicht. Im Rahmen der Zusammenfassung wurde ein Leitfaden zur Anwendung der Arbeit in Form von mehreren Fließbildern bereitgestellt. Hierdurch soll die Nutzung der entwickelten Verfahren und Methoden einem breiten Spektrum potenzieller Anwender zugänglich gemacht werden.:1 Einführung 1.1 Ausgangssituation 1.2 Zielsetzung und Lösungsweg 2 Beanspruchung von Bauteilstrukturen 2.1 Beanspruchungskomponenten ebener Strukturen 2.2 Beanspruchungskomponenten räumlicher Strukturen 2.3 Verzerrungen ebener Strukturpunkte 2.4 Das Hauptachsensystem 2.4.1 Transformation bei reiner Schubbeanspruchung 2.4.2 Transformation bei allgemeiner Beanspruchung 2.5 Hauptnormaldehnungen 2.6 Querkontraktion 2.7 Transformierte Spannungen und Hauptnormalspannungen 2.8 Mohrscher Spannungs- und Verzerrungskreis 2.9 Bezugssystemunabhängige Vergleichshypothesen 3 Messen von Beanspruchungszuständen mithilfe von Dehnungsmessstreifen (DMS) 3.1 Wirkprinzip von Dehnungsmessstreifen (DMS) 3.2 Wheatstone’sche Brückenschaltung 3.2.1 Herleitung 3.2.2 Mechanische Anwendung 3.3 Fehlereinfluss am ebenen Beanspruchungszustand 3.3.1 Fehler infolge von Scherung 3.3.2 Fehlereinfluss der Appliziergenauigkeit 3.3.3 DMS-Rosetten zur Vermeidung von Applizierungsfehlern 4 Statische Beanspruchbarkeit von Bauteilstrukturen 5 Ermüdungsfestigkeitsberechnung und Lebensdauervorhersage 5.1 Aufnahme von Wöhlerlinien 5.2 Vorgehen bei der Lebensdauervorhersage 5.3 Rechengang am Beispiel der FKM-Richtlinie 5.3.1 Begründung der Auswahl der FKM-Richtlinie 5.3.2 Werkstoffwechselfestigkeit 5.3.3 Bauteilwechselfestigkeit (konstruktiver Einfluss) 5.3.4 Auszählen des Beanspruchungsverlaufes 5.3.5 Bauteildauerfestigkeit (Mittelspannungseinfluss) 5.3.6 Bauteilbetriebsfestigkeit (Einfluss des Beanspruchungsverlaufes) 5.3.7 Nachweis und Berechnung der Lebensdauer 6 Ermittlung des Beanspruchungsverlaufes an Brückenkrantragwerken 6.1 Hauptbelastungsgrößen des Krantragwerks 6.2 Rekonstruktion des Beanspruchungs-Zeit-Verlaufes 7 Verfahren zur Erfassung der Kranbelastungsgrößen 7.1 Bedarfsbegründung des Verfahrens 7.2 Theoretische Herleitung des Verfahrens 7.3 Verwendung zusätzlicher DMS 7.4 Aufnahme von Dehnungs-Kennlinien 7.5 Vorbereitung der Installation 7.6 Beispiel anhand realer Messdaten 7.7 Zusammenfassung und Ausblick der Weiterentwicklung 8 Verfahren zur Strukturüberwachung an Brückenkrantragwerken 8.1 Einführung 8.2 Theoretische Herleitung 8.3 Validierung des Verfahrens 8.3.1 Versuchsvorrichtung 8.3.2 Gekerbte Strukturbauteile 8.3.3 Geschweißte Strukturbauteile 8.3.4 Ergebnis 8.4 Anwendung am Brückenkran 8.4.1 Herleitung 8.4.2 Versuchstechnische Validierung 8.5 Fehlereinflüsse 8.5.1 Positionierung der DMS 8.5.2 Plastisches Werkstoffverhalten 8.6 Zusammenfassung und Ausblick der Weiterentwicklung 9 Ertüchtigung und Sanierung von Brückenkrantragwerken 9.1 Systematik der Struktursanierung 9.2 Beispiele der Strukturertüchtigung 9.3 Validierung erarbeiteter Sanierungsstrategien 9.3.1 Entwicklung eines Resonanzpulsators 9.3.2 Versuchsdurchführung 9.4 Zusammenfassung und Ausblick der Weiterentwicklung 10 Zusammenfassung und Anwendung dieser Arbeit 11 Ausblick

The subject of this diploma thesis are chosen parts of building technological project of pursuance of the factory building Massag in Fulnek based on the metal bearing structure. This diploma thesis contents study of realization of main technological process of the hall, financial and time plan of building, project of construction site installation, budget of the construction, time planning of works, inspection and test plan, the project of safety and protection of health at work, technological regulation of building metal bearing structure.

Thesis (MScEng (Civil Engineering))--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: Electric driven overhead travelling bridge cranes (EOHTC) form a vital part of industrial plants where heavy objects require moving. Overhead travelling cranes aid in production by allowing an uninterrupted work process on the ground while heavy loads are moved to their required locations. Various factors need consideration in determining the loads induced by an EOHTC on its support structure. In order to design such a support structure, the designer must understand and take into account the various loads that the support structure will be subject to during its lifetime. The procedure for determining the loads induced by the EOHTC on its support structure is laid out in the SANS 10160-6:2010 code of practice. This document was published in June 2010 and as a result very few worked examples exist to test the coherence of the procedure. This thesis presents an investigation into the procedure for determining the actions induced by overhead travelling bridge cranes adopted in the SANS 10160-6:2010 code of practice. The investigation was conducted by developing a software application to automatically determine the necessary crane actions needed for the design of the crane support structure, given certain input parameters. The motivation behind this was to have a tool that can calculate the crane induced loads automatically. And by developing such a tool the procedure given in the code of practice is better understood. The Java programming language was used to code the calculations with an object oriented programming approach (OOP). NetBeans, the integrated development environment for developing with Java was used to generate the required graphical user interface of the application. In addition, a Microsoft Excel calculation sheet was also developed for the purpose of comparison and verification. Whilst developing the software application, it was found that the model for the acceleration or deceleration of the crane was specific for four wheel cranes only. This model was then extended to accommodate eight and sixteen wheel cranes and incorporated into the algorithm architecture of the application. The application was successfully completed and verified using benchmarked examples. / AFRIKAANSE OPSOMMING: Elektriese oorhoofse brugkrane vorm ‘n belangrike deel van baie nywerheidsprosesse, waar dit gebruik word om swaar laste in die nywerheidsaanleg te verskuif. Oorhoofse brugkrane voeg waarde by die produksie lyn deur te sorg dat die werksproses op die grond onversteurd voortgaan terwyl swaar laste na hul vereiste posisies verskuif word. Verskillende faktore moet in ag geneem word om die nodige kraanlaste te bepaal. Hierdie laste word benodig om die kraan se ondersteuningstruktuur te ontwerp. Die ontwerper moet die nodige kundigheid hê en moet ook die verskeie laste in ag neem wat die ondersteuningstruktuur gedurende sy leeftyd sal dra. SANS 10160-6:2010 verskaf riglyne vir die bepaling van die laste wat deur oorhoofse brugkrane uitgeoefen word. Hierdie dokument is in Junie 2010 gepubliseer dus bestaan daar min uitgewerkte voorbeelde om die korrektheid van die riglyne te toets en toepassing te demonstreer. Hierdie proefskrif ondersoek die riglyne vir die bepaling van oorhoofse brugkraan aksies soos uiteengesit in die SANS 10160-6:2010. Die navorsing is uitgevoer deur middel van die ontwikkeling van ‘n sagteware toepassing wat die nodige oorhoofse brugkraanlaste automaties bepaal, gegee sekere invoer waardes. Die rede hiervoor was om ‘n hulpmiddel te ontwikkel vir die outomatiese bepaling van oorhoofse brugkraan. Deur die bogenoemde hulpmiddel te ontwikkel word die riglyne, soos gegee in die kode beter verstaan. Java is gebruik as programmeringstaal waar die objek geörienteerde programeringstyl toegepas was. Die geintegreerde ontwikkelingsomgewing vir ontwikkeling met Java, naamlik NetBeans is gebruik om die nodige gebruikers koppelvlak op te bou. ‘n Microsoft Excel sigblad is ook ontwikkel vir kontrolerings doeleindes. Gedurende die ontwikkeling van die sagtewarepakket is dit bevind dat die lasmodel vir die versnelling of vertraging van die oorhoofse brugkraan slegs op vierwiel krane van toepasing is. Hierdie lasmodel is dus uitgebrei om agt- en sestienwiel krane ook te bevat. Die lasmodel aanpassing is dan ook in die program se algoritme-argitektuur ingebou. Die sagteware toepassing is suksesvol ontwikkel en gekontroleer met ‘n maatstaf voorbeeld.

O problema de transferir uma carga ao se movimentar num plano em tempo mínimo e sem oscilação no ponto de descarga, num guindaste portuário tipo pórtico é investigado neste trabalho. Assume-se que a carga esteja inicialmente em repouso na posição vertical no ponto de carga acima do navio e igualmente em repouso no ponto de descarga na moega de alimentação no porto. Assume-se também que o carro do guindaste esteja em repouso em ambos os pontos. Um modelo completo é apresentado para o sistema do guindaste onde as equações dinâmicas não-lineares são linearizadas para ângulos de oscilação pequenos o suficiente e reescritas para a forma adimensional. A solução de tempo mínimo é buscada considerando como variáveis de controle as funções do tempo que descrevem tanto a força aplicada no carro para produzir seu deslocamento horizontal, como a velocidade de içamento da carga. Um método iterativo preditor-corretor usando a Programação Linear (PL) é proposto, baseado no modelo do sistema de tempo discreto onde as variáveis de controle são tomadas constantes por trechos. Na etapa corretora, assume-se que o movimento de içamento é dado e uma solução de tempo mínimo é obtida resolvendo-se uma seqüência de problemas de PL de tempo fixo e máximo deslocamento. Na etapa preditora, um modelo linearizado é empregado para obter-se uma correção ótima do movimento de içamento usando a PL. O problema de controle de tempo mínimo é formulado levando-se em consideração restrições práticas na velocidade do carro do guindaste, velocidade máxima de içamento, assim como na máxima força que pode ser aplicada ao carro. Resultados numéricos são apresentados e mostram a efetividade do método. / The problem of minimum-time anti-swing transfer of a load in a ship-to-pier gantry crane is investigated in this work. The load is assumed to be initially at rest at the vertical position at the loading point above the ship and equally at rest at the unloading point above the hopper. The trolley is also assumed to be at rest at both points. A complete model is presented for the crane system where the nonlinear dynamic equations are linearized for sufficiently small swing angles and then rewritten in dimensionless form. The minimum-time solution is sought by considering as control variables both the force applied on the trolley that produces its horizontal motion and the hoisting speed of the load as functions of time. A predictor-corrector iterative method using Linear Programming (LP) is proposed based on a discretetime model of the system where the control variables are taken as stepwise constants. At the corrector step, the hoisting motion is assumed given and a minimum-time solution is obtained by solving a sequence of LP problems representing fixed-time maximum-range problems. At the predictor step, a linearized model is employed to obtain an optimal correction of the hoisting motion using LP. The minimum-time control problem is formulated by taking into account practical constraints on the maximum speeds of both the trolley and the load hoisting, as well as on the maximum force that can be applied to the trolley. Numerical results are presented and show the effectiveness of the method.

Este trabalho apresenta a análise de provas de carga dinâmica realizadas em estaca metálicas tipo trilho (TR - 68) cravadas no Campo Experimental de Fundações da USP/São Carlos. As estacas possuem segmentos de 12 e de 3 m, soldados segundo a NBR 8800/86, totalizando um comprimento máximo 27 m. Os objetivos desta análise são: 1) realizar um estudo abrangente da capacidade de carga do tipo trilho, 2) verificar a utilização de trilho usado como elemento estrutural de fundação, 3) comprovar o uso do repique como método de controle do estaqueamento, 4) demostrar a importância da energia crescente na prova de carga dinâmica. As medidas de repique foram realizadas com o uso de papel e lápis em vinte estacas, para níveis crescentes de energia. A energia foi aplicada pelo martelo de gravidade caindo de uma altura de 0,20 - 0,40 - 0,60 - 0,80 - 1,00 - 1,20 e 1,50 m. A capacidade de carga das estacas, determinada pela extrapolação da curva carga mobilizada - deslocamento, foi comparada com os valores obtidos pelos métodos de previsão da prática brasileira, bem como com os resultados de dois ensaios com PDA (Pile Driving Analyzer) e também com uma prova de carga estática, realizados em estacas representativas. / This paper presents an analysis of dynamic load tests performed on steel crane rails piles (TR-68) at the Experimental Foundation Field of USP/São Carlos. The piles have segments of 12 and 3 m, welded according to NBR 8800/86, comprising a maximum driving length of 27 m. The objectives of this analysis are: 1) to carry out a wide study of steel track pile bearing capacity, 2) verify the utilization of the steel crane rails piles with structural element of foundation, 3) to prove the use of the rebound with the control method of driving piles. 4) to demonstrate the importance of increasing energy in the dynamic load test. The rebound measurements were performed with paper and pencil in twenty piles and were analyzed by applying increasing energy level. The energy was applied by the gravity hammer falling of a drop heights of 0.2 - 0.4 - 0.6 - 0.8 - 1.0 - 1.2 and 1.5 m. The pile bearing capacity, determined by the extrapolations of the mobilized resistance - displacement curves was compared to the Brazilian experience methods, as well as to two load tests employing the Pile Driving Analyzer (PDA) and to one static load test carried out on representative piles.

As vigas de rolamento são estruturas destinadas ao suporte de pontes rolantes, estas amplamente utilizadas para movimentação de cargas em galpões industriais. O presente trabalho apresenta um estudo sobre as vigas de rolamento de aço sem contenção lateral entre apoios, em geral projetadas com vão inferior a 7 metros, portanto destinadas ao suporte de pontes rolantes leves (capacidade nominal até 250 kN). A ausência de contenções laterais intermediárias aliada ao desalinhamento e à imprecisão na locação dos trilhos, bem como à presença de forças horizontais transversais ao eixo da viga (aceleração/frenagem do trole), impõem flexão lateral e torção, esforços que são equilibrados apenas pelas contenções nos apoios. A análise foi realizada utilizando o Método dos Elementos Finitos (MEF), considerando a análise não linear física e geométrica do problema, ou seja, um modelo mais próximo da viga real. Os resultados numéricos, quando comparados aos obtidos por meio da teoria de flexo-torção, mostraram uma inversão na distribuição esperada de tensões na mesa superior do perfil, ou seja, nos pontos onde deveria ocorrer aumento da tensão longitudinal de compressão, ocorreu redução. Esta inversão pode ou não ocorrer, dependendo da espessura da mesa superior, intensidade e posição da força vertical da roda da ponte. Além disso, os resultados determinados via MEF foram comparados com os obtidos via modelo tradicional de barra (momento de torção substituído por um binário de forças horizontais nas mesas). A comparação indicou divergência entre os resultados, podendo o dimensionamento pelo modelo de barra levar tanto a situações a favor da segurança como contra a segurança. / The runway girders are structures intended for support cranes, these broadly used to movement of loads in industrial buildings. This research presents a study about the runway girders without lateral bracing between support points, generally designed with span lower than 7 meters, therefore intended for support of light cranes (rated capacity until 250 kN). The absence of intermediate lateral bracing allied to misalignment and imprecision location of the rail, also the presence of the side thrust on the girder (acceleration/ braking of the trolley), causes lateral flexural and torsion, which are balanced only by the lateral containment on support points. The analysis was made using the Finite Element Method (FEM), which includes a nonlinear physical and geometric analysis of the structural problem, in other words, a model closest to the real girder. The numerical results, when compared to the results of the flexural-torsional theory, showed an inversion in the expected distribution of stress on the top flange of the shape, in other words, at the points where must occur increase of the longitudinal stress, reduction occurred. This inversion may or may not occur, depending on the thickness of the top flange, modulus and position of the load of the crane wheel. Besides, the numerical results were compared with the results of classical bar model for beams (torque is replaced by a couple of horizontal forces applied on the flanges). The comparison showed a divergence between the results, where the design by bar classical model can lead to situations of high safety or against safety.

<p>Disertacija obrađuje problematiku praktičnog uvođenja opterećenja izazvanih<br />zako&scaron;avanjem dizalice u normiranu proceduru dokaza zamorne čvrstoće njene noseće<br />konstrukcije. U prvom delu rada koncizno je izložena teorijska podloga zako&scaron;avanja<br />mosne dizalice, neophodna za potpunije razumevanje relevantnih obeležja predmeta<br />istraživanja. Predložene su metode za eksperimentalnu determinaciju bočnih sila u<br />interakciji točak &ndash; &scaron;ina, odn. vodeća rolna &ndash; &scaron;ina. Testiranje predloženih metoda<br />spovedeno je kroz eksperimente na realnom objektu &ndash; jednogredoj električnoj mosnoj<br />dizalici nosivosti 3,2 t i raspona 8,91 m. Komentarisani su reprezentativni rezultati i<br />date su smernice za sprovođenje dokaza zamorne čvrstoće detalja noseće konstrukcije<br />dizalice, uzimajući u obzir pri tom i spektre sila zako&scaron;enja. Takođe je ukazano i na<br />neke nejasnoće i nedorečenosti u važećim standardima, a u vezi proračunskog<br />određivanja sila zako&scaron;enja.</p> / <p>The dissertation deals with the problem of practical application of loadings caused by<br />crane skewing, in normative procedures of fatigue strength proof calculations of crane<br />supporting structure. In the first part, the theoretical framework of bridge crane<br />skewing, necessary for better understanding of relevant characteristics of the research<br />topic, has been concisely elaborated. Methods are proposed for experimental<br />determination of lateral forces in wheel/rail and guiding roller/rail contacts. These<br />methods were tested through a series of experiments on a real object &ndash; an electrically<br />driven single girder bridge crane with a capacity of 3.2 t, and span 8.91 m. Some<br />representative measurement results are discussed and guidelines are given for<br />performing the fatigue strength proof calculation of crane supporting structure details,<br />taking into account skewing forces spectra, too. Also, attention has been drawn to<br />certain unclear points and inconsistencies in norms in force, concerning calculative<br />determination of skewing forces.</p>

This dissertation examines American attitudes towards death from the colonial era to the end of the nineteenth century. I begin with a close analysis of the thanatology of the Congregational church in New England, before demonstrating the lasting influence of Puritan thought on three later writers: Jonathan Edwards, Henry David Thoreau and Stephen Crane. In contrast to purely cultural studies of mortality in America (including those by Phillipe Ariès, David Stannard and Michael Steiner), my investigation discusses the philosophical difficulties that obstruct any attempt to speak about death. Building on Jacques Derrida’s work in Aporias (1993), I identify three logical impasses that interrupt Puritan writing on mortality: the indeterminacy, singularity and finality of death. While Edwards, Thoreau and Crane write in different circumstances and diverse genres, I argue that they are sensitive to these same three aporias when they discuss death. In this regard, they resist a broader post-Puritan tendency (in both scientific and sentimental texts) to minimize the uncertainties surrounding human mortality and approach death as a universal (rather than radically singular) phenomenon. While my study situates each of its authors in the cultural and intellectual contexts in which they worked, it also challenges the notion that it is possible to write a history of death. Speaking strictly, mankind’s relationship to death can never change. It is always, in fact, a non-relation. The very idea of death destabilizes our most fundamental historical and literary assumptions. Accordingly, my second chapter uses a deconstruction of Edwards’ theory of revivalism to argue that the New-England awakenings of the eighteenth century expressed the converts’ desire to renounce responsibility for their souls, rather than accept it. In my third chapter, I argue that those writings in which Thoreau registers what might seem to be a nihilistic fascination with dead and decaying bodies in fact express a sentimental desire for a peaceful death. Chapter four reads Stephen Crane’s poetry, fiction and journalism in the context of his Calvinist heritage, breaking down the distinction between his textual play with the concept of death and the Puritans’ “serious” attempts to come to terms with mortality.

This dissertation examines American attitudes towards death from the colonial era to the end of the nineteenth century. I begin with a close analysis of the thanatology of the Congregational church in New England, before demonstrating the lasting influence of Puritan thought on three later writers: Jonathan Edwards, Henry David Thoreau and Stephen Crane. In contrast to purely cultural studies of mortality in America (including those by Phillipe Ariès, David Stannard and Michael Steiner), my investigation discusses the philosophical difficulties that obstruct any attempt to speak about death. Building on Jacques Derrida’s work in Aporias (1993), I identify three logical impasses that interrupt Puritan writing on mortality: the indeterminacy, singularity and finality of death. While Edwards, Thoreau and Crane write in different circumstances and diverse genres, I argue that they are sensitive to these same three aporias when they discuss death. In this regard, they resist a broader post-Puritan tendency (in both scientific and sentimental texts) to minimize the uncertainties surrounding human mortality and approach death as a universal (rather than radically singular) phenomenon. While my study situates each of its authors in the cultural and intellectual contexts in which they worked, it also challenges the notion that it is possible to write a history of death. Speaking strictly, mankind’s relationship to death can never change. It is always, in fact, a non-relation. The very idea of death destabilizes our most fundamental historical and literary assumptions. Accordingly, my second chapter uses a deconstruction of Edwards’ theory of revivalism to argue that the New-England awakenings of the eighteenth century expressed the converts’ desire to renounce responsibility for their souls, rather than accept it. In my third chapter, I argue that those writings in which Thoreau registers what might seem to be a nihilistic fascination with dead and decaying bodies in fact express a sentimental desire for a peaceful death. Chapter four reads Stephen Crane’s poetry, fiction and journalism in the context of his Calvinist heritage, breaking down the distinction between his textual play with the concept of death and the Puritans’ “serious” attempts to come to terms with mortality.