M.Tech. (Civil Engineering) / Every year, millions of Rands are being spent in rehabilitation, repairs and maintenance of reinforced concrete structures projects around the country due to corrosion. There are a number of studies and investigations that have been done recently to address the effect of corrosion on reinforced concrete structures. Concrete provides an ideal environment for steel, supplying both physical and chemical protection from corrosive attack. The effect of corrosion on reinforced concrete structures contributes to the reduction of steel cross sectional area, weakening the bond strength between steel and concrete and thereby reducing the ductility, deflection capacities and load carrying capacity of the structure. In this research, five series of three samples each of reinforced concrete beams were fabricated, some with reduced cross-sectional area and with exposed bars to simulate loss of bonding through spalling. The structural performance of these beams was tested in terms of maximum load carrying capacity, deflections and ductility ratio. The main conclusions are as follows:  As little as 1 % loss in mass of tension steel resulted in a load carrying capacity decrease of 6.9 %  Beam deflection increased by a factor of 1.5 times when the steel mass loss level was 14%  5 % steel loss in mass resulted in a 16.5 % decrease in relative ductility.

M.Tech. (Civil Engineering) / The results of an investigation on the local buckling of cold-formed stainless steel compression sections arc presented in this dissertation. The stainless steel under consideration is AISI Type 304 Austenitic, manufactured by the South African based speciality steel producing company Middelburg Steel & Alloys. All sections were manufactured by press braking process. The purpose of this investigation was to study the critical buckling stress and buckling coefficient (k), of cold-formed, partially stiffened stainless steel compression elements in order to determine the applicability of the current design specification. The mechanical properties of the stainless steel under consideration as well as the results of 28 partially stiffened double hat sections are compared with theoretical predictions. It was concluded in this study that the experimental results of the critical buckling stress compare well when using the plasticity reduction factor Es/Eo in the theoretical predictions. However the theoretical buckling coefficient (k) shows to be not representative to the experimental results obtained in this investigation.

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A36 steel is a commonly used material in civil engineering structures where fatigue damage can lead to catastrophic failure. In this research, nonlinear Rayleigh surface waves are used to characterize damage in A36 steel specimens caused by monotonic tension and low cycle fatigue. Fatigue damage produces the increased acoustic nonlinearity that leads to the generation of measurable higher harmonics in an initially monochromatic Rayleigh wave signal. One specimen is subjected to static tension and four specimens are used for low cycle fatigue tests in the tension-tension mode with a constant stress amplitude. The fatigue tests are interrupted at different numbers of cycles for the nonlinear ultrasonic measurements. Tone burst Rayleigh wave signals are generated and detected using a pair of oil coupled wedge transducers. The amplitudes of the first and second harmonic are measured at varying propagation distances to obtain the nonlinearity parameter for a given damage state. The experimental results show an increase of acoustic nonlinearity in the early stages of fatigue life. Furthermore, a close relationship between plastic deformation and the acoustic nonlinearity is found, which indicates that the acoustic nonlinearity is indeed a measure of microplasticity in this material.

Thesis (M.App.Sc.) - Carleton University, 2006. / Includes bibliographical references (p. 180-185). Also available in electronic format on the Internet.

Thesis (MScEng)--Stellenbosch University, 2003. / ENGLISH ABSTRACT: AP230 of STEP is an application protocol for structural steel-framed buildings. Product data relating to steel structures is represented in a model that captures analysis, design and manufacturing views. The information requirements described in AP230 were analysed with the purpose of identifying a subset of entities that are essential for the description of simple industrial steel frames with the view to being able to describe the structural concept, and to perform the structural analysis and design of such structures. Having identified the essential entities, a relational database model for these entities was developed. Planning, analysis and design applications will use the database to collaboratively exchange data relating to the structure. The comprehensiveness of the database model was investigated by mapping a simple industrial frame to the database model. Access to the database is provided by a set of classes called the database representative classes. The data-representatives are instances that have the same selection identifiers and attributes as corresponding information units in the database. The datarepresentatives' primary tasks are to store themselves in the database and to retrieve their state from the database. A graphical user interface application, programmed in Java, used for the description of the structural concept with the capacity of storing the concept in the database and retrieving it again through the use of the database representative classes was also created as part of this project. / AFRIKAANSE OPSOMMING: AP230 van STEP is 'n toepassingsprotokol wat staal raamwerke beskryf. Die produkdata ter beskrywing van staal strukture word saamgevat in 'n model wat analise, ontwerp en vervaardigings oogmerke in aanmerking neem. Die informasie vereistes, soos beskryf in AP230, is geanaliseer om 'n subset van entiteite te identifiseer wat noodsaaklik is vir die beskrywing van 'n eenvoudige nywerheidsstruktuur om die strukturele konsep te beskryf en om die struktuur te analiseer en te ontwerp. Nadat die essensiële entiteite geïdentifiseer is, is 'n relasionele databasismodel van die entiteite geskep. Beplanning, analise en ontwerptoepassings maak van die databasis gebruik om kollaboratief data oor strukture uit te ruil. Die omvattenheid van die databasis-model is ondersoek deur 'n eenvoudige nywerheidsstruktuur daarop afte beeld. Toegang tot die databasis word verskaf deur 'n groep Java klasse wat bekend staan as die verteenwoordigende databasis klasse. Hierdie databasis-verteenwoordigers is instansies met dieselfde identifikasie eienskappe as die ooreenkomstige informasie eenhede in die databasis. Die hoofdoel van die databasis-verteenwoordigers is om hulself in die databasis te stoor asook om hul rang weer vanuit die databasis te verkry. 'n Grafiese gebruikerskoppelvlak, geprogrammeer in Java, is ontwikkel. Die koppelvlak word gebruik om die strukturele konsep te beskryf, dit te stoor na die databasis en om dit weer, met behulp van die databasis-verteenwoordigers, uit die databasis te haal.

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A cyclic polarization procedure was designed to evaluate the pitting potentials of high performance stainless steels in synthetic concrete pore water at different chloride concentrations. Cyclic polarization scans were performed on high performance stainless steel reinforcements, S32201, S32305 and S32205. Pitting initiation was observed below the oxygen evolution potential for high chloride concentrations. S32201 and S32304 showed the presence of metastable pitting before reaching its pitting potential. Pitting resistance performance, based on cyclic polarization, was consistent with each material's respective Pitting Resistance Equivalent Number (PREN) value. For S32201 and S32304, pitting potential decreased as the chloride concentration increased, whereas S32205 did not pit at the chloride concentrations tested. / by Erika Maria Sanchez. / Thesis (M.S.C.S.)--Florida Atlantic University, 2011. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2011. Mode of access: World Wide Web.

The design of bridge structures to resist explosive loads has become more of a concern to the engineering community. This thesis proposes a method to evaluate the effects of conventional blast loads on a two span continuous composite steel girder bridge system. The bridge design is based on AASHTO LRFD method. Resistance capacities of bridge deck and composite steel girder are calculated according to AASHTO specifications. Equivalent blast pressures on the bridge components are obtained. Response and performance of concrete deck, steel girders, and supporting piers are evaluated under typical blast loads. The blast induced force in the bridge components are computed in the static analyses for varying amounts of TNT. The blast effects in the supporting pier are determined using both static and dynamic analyses. Further research needs to be done in the dynamic analysis of the bridge system subjected to blast loads. / by Fang Zhou. / Thesis (M.S.C.S.)--Florida Atlantic University, 2009. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2009. Mode of access: World Wide Web.