This thesis is concerned with the seismic design of bridge piers. Particular attention is given to lifeline bridges with reinforced concrete hollow columns. Development of an analytical model to predict the stress-strain behaviour of reinforcing steel under dynamic cyclic loading is presented. Model predictions agreed well with previous tests on mild and high strength steel specimens. A generalised stress-strain model for plain or confined concrete under dynamic cyclic axial compression loading is presented. To verify the model, axial compression tests were carried out on 15 circular columns with spiral reinforcement, 16 rectangular walls and five square columns with rectilinear hoops. Theoretical predictions compared well with the experimental behaviour of the near full size specimens. A ductile design methodology for lifeline bridges is presented. Inelastic response spectra for "maximum credible" earthquake motions were derived for structures with concrete columns. These design spectra can be used to assess ductility demand of column hinges. Using the steel and concrete stress-strain models, a theoretical model is developed to predict the lateral load-deformation behaviour, and thus ductility capability, of reinforced concrete columns under axial load and cyclic flexure. Design charts are prepared to enable the rotational capacity of columns with confined concrete to be assessed. Finally, an experimental investigation into the seismic performance of ductile hollow reinforced concrete columns is described. Four specimens, 40 percent full size, containing different amountsof confining steel in the plastic hinge zone were subjected to a constant axial load and cyclic lateral displacements. An assessment of the effect of axial load and the amount of confining steel on the rotational capacity of the plastic hinge is made. The specimens performed satisfactorily, obtaining member ductilities between 6 and 8, without any significant strength degradation under cyclic loading. Predictions from the proposed lateral load- deformation model are found to compare well with the experimental results.

Thesis (M. S.)--Civil and Environmental Engineering, Georgia Institute of Technology, 2009. / Committee Chair: Sturm, Terry; Committee Member: Burns, Susan; Committee Member: Webster, Donald. Part of the SMARTech Electronic Thesis and Dissertation Collection.

Thesis (M.M.P.)--University of Delaware, 2008. / Principal faculty advisor: Gerard J. Mangone, College of Marine & Earth Studies. Includes bibliographical references.

The main objective of this research is to estimate the sizes of riprap (loose rock) on highway or railroad embankments approaching bridges, that would be stable in major floods. Two assumptions about the flow direction were made: one horizontal to the bridge abutment and the other normal to the projection of the bridge abutment. Three dynamic conditions of stability of riprap were observed and classified as shaking, some movement, and large movement (washing out). Shaking is the most conservative criteria for design because it indicates more stability than is necessary, requires larger rock, and is less cost efficient. Some movement suggests a conservative design criteria and is the most desirable because it requires smaller riprap and is therefore less expensive. Large movement or washing out means the least stable condition; it may leave the structure as well as human lives exposed to danger.

No description available.

published_or_final_version / Architecture / Master / Master of Landscape Architecture

This thesis is a contribution to the existing knowledge of the nature of the scour hole around bridge piers. The analysis is based on the fictitious, long contraction concept developed by Dr. Emmett M. Laursen. This concept and its equation has been used herein to determine the size of rip-rap particles which will reduce the local scour at bridge piers. Evaluation of the parameters involved in it is required for sizing the rocks in a prototype. Values such as approach velocity, water depth, average diameter of the rip-rap particles in the scour, and geometry of the pier are among the values to be known. Both a graphic and an analytical procedure are proposed as a means to find the size of particles to be used as protection. The discussion and conclusions derived from this investigation will be of great help to civil engineers working in the field of river engineering.

Langland's use of moral distichs from the medieval text known as the Disticha Catonis has been noted but never critically examined as a whole. The figure of 'Cato' and the distichs attributed to him stand out in Piers Plowman. I will begin by placing both Piers and the Disticha in their medieval literary context. Questions of audience and literacy have always been central to Piers, and I will look at the way in which Langland's use of Latin quotations from the Disticha relates to these issues. I will also examine the role of ' Cato' and the distichs in Piers in order to dispell the prevailing critical view that 'Cato' represented a pagan authority. The medieval Christian commentaries which accompanied the Disticha illuminate Piers as well. Critics have often wondered why Langland choose to write in a mixture of languages. 'Cato' and the Disticha are part of the answer. / Graduate

No description available.

The dissertation examines the early reception of Piers Plowman through the responses of the poem's early readers and copyists in order to revive the context in which the poem was originally read and understood. These responses are derived from manuscript evidence. The dissertation is divided into five chapters, and begins with an examination of the background to the study, previous work on and assumptions about the reception of the poem. This is followed by a discussion of the theory of reception of literary works, and its relevance to MS studies, thus setting out the theoretical basis of the dissertation. A brief discussion of methodology follows. The next three chapters analyse the evidence from the MSS, examining respectively the contributions of the professional book producers in terms of layout, decoration and rubrication; readers' comments, usually in the form of marginalia; and the contribution of the scribes, through alteration of the text. The concluding chapter draws together the evidence from all three areas of analysis and discusses the relevance of the study to the understanding of the poem. There are four appendices, the first providing a list of early poems associated with Piers Plowman in the sixteenth century, and a list of names associated with the poem before Robert Crowley printed the poem in 1550. The other three appendices provide evidence from the MSS, respectively descriptions of all the Piers Plowman MSS; all the professional rubrication from the MSS; full readers' annotation from selected MSS, Digby MS 145, BL Additional 35287, Douce MS 104, and BL Additional 35157, the reader's wordlist from CUL L1 4.14, and glossed words from TCD MS 212. These appendices are included to provide as much evidence as possible from the MSS in a readily accessible form.