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The object of this thesis is twinfold. Firstly, to study and check the effective width requirements recommended by different committees¹ for the design of ribbed precast concrete load bearing walls. Secondly, to rationalize the practice of the designing of the precast prefabricated components of any general polygonal shape. The recommendations regarding the minimum thickness of a thin wall, the effective width, etc., have been specified for some cases in code books and other tentative specification books², in the form of rules of thumb. In these rules of thumb, several parameters which may be of significance, such as dimensions of the rib itself, are not taken into account. A finite element approach has been adopted to investigate various combinations of these parameters, as well as the effects of different boundary conditions. Similar problems arise also in the cases of T-beams, L-beams and design of aircraft structures, in which a stressed skin is mounted on ribs, which are assembled in the form of a space frame. So far interaction curves have been made available in some design books only for the prestressed concrete member having rectangular cross-sections and for any other shape, approximations are made, such as making a rectangular section having an equivalent area or having the same moment of inertia or section modulii, etc. But this practice seems very irrational especially in the case of precast components which are always produced in a factory on a mass scale. A computer program has been written which can give the interaction curve for the member of any polygonal shape. 1. DRAFT 3: Of PCI Committee, 'Recommendations for Prestressed Bearing Wall Design.' 2. 'Symposium on Precast Concrete Wall Panels.' Publications ACI, SP-11, Second Printing 1966, pp. 39-44. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

M.Ing. (Civil Engineering) / The shear strength of a concrete structure is usually determined in practice in accordance with the applicable national concrete design code. Calculation methods prescribed in national design codes differ from code to code and yield widely divergent results. The methods given for different cases in specific codes are often based on different approaches. Further, some of the methods do not agree with the observed behaviour during failure. This shows that there is a need for more accurate methods of determining shear strength, as well as approaches leading to universally applicable methods. A literature study was undertaken to establish whether such methods or approaches have already been developed. Special attention was given to the underlying mechanisms involved in shear resistance, to the shear resistance of concrete elements without shear reinforcement, of elements with varying depth, and of areas near points of contraflexure, and to punching resistance of flat slabs. A review of the latest research on the subject is given, and areas where further research is required, are identified.

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A thesis submitted to the Faculty of Engineering, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Doctor of Philosophy / The cracking of mass and structural concrete due to thermal stress is a major problem in the concrete construction industry. Concrete will crack when the thermal stress exceeds tbe tensile strength of the concrete, Decisions on the type of concrete mix, cooling facilities and construction techniques to be used in the erection of a concrete structure can only be made if the thermal behaviour and strength of the concrete can be predicted during hydration. This thesis describes the development of a low cost, computer controlled, adiabatic calorimeter to determine tlte heat of hydration and a probe to determine the thermal conductivity or concrere samples. The main thrust of this thesis is the development of the thermal conductivity probe which, for the first time, can measure the thermal conductivity of concrete through all stages of hydration. A thermal model was also developed to verify the results, and the use of the calorimeter for temperature matched curing tests is also discussed. Results, obtained from the test procedures described, will provide far more accurate predictions of the temperatures in concrete structures than was possible in the past. / Andrew Chakane 2018

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Thesis (M.S.)--Oregon State University, 2009. / Printout. Includes bibliographical references (leaves 73-77). Also available on the World Wide Web.

The FDOT has been using supplementary cementitious materials while constructing steel reinforced concrete marine bridge structures for over 3 decades. Previous findings indicated that such additions in concrete mix makes the concrete more durable. To better understand corrosion propagation of rebar in high performance concrete: mature concrete samples that were made (2008/2009) with Portland cement, a binary mix, a ternary mix and recently prepared (April 2016 with 50% OPC + 50% slag and 80% OPC + 20% Fly ash) concrete samples were considered. None of these concretes had any admixed chloride to start with. An accelerated chloride transport process was used to drive chloride ions into the concrete so that chlorides reach and exceed thechloride threshold at the rebar surface and initiate corrosion. Electrochemical measurements were taken at regular intervals (during and after the electro-migration process) to observe the corrosion propagation in each sample. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2017. / FAU Electronic Theses and Dissertations Collection

Thesis (M.S.)--Oregon State University, 2010. / Printout. Includes bibliographical references (leaves 120-125). Also available on the World Wide Web.