SEISMIC ANALYSIS OF INTEGRAL ABUTMENT BRIDGES CONSIDERING SOIL STRUCTURE INTERACTION

Integral abutment bridges are jointless bridges in which the deck is continuous and connected monolithically with the abutment walls supported typically by a single row of piles. This thesis focuses on the effects of two major parameters on the seismic behavior of an integral abutment bridge in Tennessee by considering soil-structure interaction around the piles and in back of the abutments: (1) clay stiffness (medium vs. hard) around the piles, and (2) level of sand compaction (loose vs. dense) of the abutment wall backfilling. Modal and nonlinear time history analyses are performed on a three dimensional detailed bridge model using the commercial software SAP2000, which clearly show that (1) compacting the backfilling of the abutment wall will increase the bridge dominant longitudinal natural frequency considerably more than increasing the clay stiffness around the piles; (2) the maximum deflection and bending moment in the piles under seismic loading will happen at the pile-abutment interface; (3) under seismic loading, densely-compacted backfilling of the abutment wall is generally recommended since it will reduce the pile deflection, the abutment displacement, the moments in the steel girder, and particularly the pile moments; (4) under seismic loading, when the piles are located in firmer clay, although the pile deflection, the abutment displacement, and the maximum girder moment at the pier and the mid-span will decrease, the maximum pile moment and the maximum girder moment at the abutment will increase

A Critical Inspection of Socio-Cultural Realities in American Society Based on Tony Kushner's Angels in America with the Ethical Lens of Emmanuel Levinas

Political theater reveals the problematic issues of a society to make its audience stand up for their suppressed rights and to compel the States to make political and social reforms. Although the American politicians claim to have established justice, equality and morality, the marginal minorities have lost their identity in the American society as a result of the discrimination imposed by the government and the mainstream. This Article aims at depicting the dark reality and the real position of marginal minorities in the American society as well as the solution of this issue suggested by Tony Kushner in his play Angels in America. This study was conducted under the light of Levinasian ethical principles and his concepts of the other and face to face encounter. Having scrutinized Angels in America, it was found that marginalizing the minorities causes them not to participate in social movements and also to hide their real identity. Also the result of this study showed that solidarity, hope and social activism are the solution to prevent the devastation of the American society. More political theories can be taken to reduce ethical problems that America is faced with as well as in the Middle East

Functionalism in Translation: A Case Study Investigation into Translation literature based on Nord's Documentary vs. Instrumental Dichotomy

The main objective of the current study was to analyze a Persian Translation of a short story from functionalism perspective and Documentary vs. Instrumental Dichotomy. To this end, the Persian translation of the book titled “The Little Prince” was analyzed and compared with its English version (indirect translation from French) to see if the Persian translation was more documentary or instrumental oriented in nature. The theoretical framework of the study was Nord’s dichotomy of instrumental vs. documentary translation. The book was analyzed at the sentence and above sentence level and covered the whole book. As the qualitative analysis showed, the translation of the book was instrumental oriented, and the book reads like an original in the target language

Insights into climate-driven evolution of gas hydrate-bearing permafrost sediments

Massive reserves of natural gas hydrates exist in permafrost and marine sediments. Dissociation of natural gas hydrates could result in enhanced emissions of methane to the atmosphere, aggravating global warming. It may also become a serious geohazard to the geomechanical stability of gas hydrate deposits. The environmental and infrastructural impacts due to climate-driven and human-induced dissociation of natural gas hydrates cannot be well predicted unless we have an accurate estimation of hydrates deposited in both marine and permafrost sediments. However, conventional seismic techniques cannot give reliable estimations of gas hydrates in permafrost sediments as they are unable to distinguish ice from hydrates due to their almost identical acoustic properties. The main objective of this thesis is to address the above challenge via shedding light on the influence of the hydrates presence on the evolution of gas hydrate-bearing permafrost sediments, and developing a coupled geophysical-geothermal scheme, for the first time, for estimation of hydrates saturation in these sediments. To achieve this, magnetic resonance imaging (MRI) was employed to investigate the kinetics of formation and spatial characteristics of methane hydrate in synthetic and natural sediment samples. The analysis of the images acquired during three consecutive thermally-induced hydrate formation/dissociation cycles indicated that in addition to the kinetics of formation, pore-scale distribution of hydrates is affected by the thermal history of the system and the host sediment type, characteristics, and particle size distribution. The results also showed that different hydrate pore-scale habits may co-exist in the system, which is essential to be considered in the models developed for the estimation of the physical properties of gas hydrate-bearing sediments. Having the above fundamental insights, the geophysical and geothermal responses of hydrate-free and hydrate-bearing sediments were characterised by measuring their elastic wave velocities and effective thermal conductivity (ETC) at different hydrate saturations (up to 55%) and effective overburden pressures (up to 6.89 MPa) at both unfrozen and frozen conditions. The results confirmed that the evolution of the elastic wave velocities as well as ETC depends on the saturation and pore-scale habit of hydrates; and ETC could interestingly assist with distinguishing ice from hydrates. The ETC measurements also revealed that the presence of hydrates in porous media is associated with three key pore-scale phenomena contributing to the efficiency of the heat transfer: the saturation and pore-scale habit of hydrates, hydrate/ice-forced heave, and unfrozen water saturation at frozen conditions. Moreover, a new physical model was developed for the prediction of ETC of hydrate-free sediments using the Free-energy Lattice Boltzmann Model (LBM) and a space renormalisation technique, and modified according to the insights from the ETC measurements to account for the effect of the above-mentioned key pore-scale phenomena. Ultimately, the coupled geophysical-geothermal scheme was developed by using the modified ETC model as the geothermal part and Ecker’s rock-physics models as the geophysical part, and its performance was validated using the measured geophysical and geothermal properties. It was demonstrated that the proposed coupled scheme is able to quantify the saturation of the co-existing phases in a wide range of hydrate saturations and at different effective overburden pressures, particularly at frozen conditions where the co-existence of hydrates, ice, and unfrozen water is essential to be captured. This scheme makes it possible to distinguish ice from gas hydrates in frozen sediments hence it could be employed for not only quantification of gas hydrates in permafrost but also further development of large-scale permafrost monitoring systems for monitoring the dynamic response of gas hydrate-bearing permafrost sediments to climate warming in cold regions.James Watt Scholarshi