A new ultimate limit state approach to the design of prestressed concrete beams

 

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dc.contributor.advisor Kratz, Rolf Dietmar en_ZA
dc.contributor.author Hallam, Grant Robert en_ZA
dc.date.accessioned 2016-09-28T19:00:39Z
dc.date.available 2016-09-28T19:00:39Z
dc.date.issued 1990 en_ZA
dc.identifier.citation Hallam, G. 1990. A new ultimate limit state approach to the design of prestressed concrete beams. University of Cape Town. en_ZA
dc.identifier.uri http://hdl.handle.net/11427/21967
dc.description.abstract The present approach to the design of prestressed beams is antiquated and time consuming. Neither SLS or ULS requirements are satisfied directly. There is a need for a new approach using plastic principles to design the prestressing requirements at ULS considering a whole span at a time, with checks made for SLS requirements afterwards. For a plastic design, the designer would need to know the limits of the bending moment redistribution for the beam under consideration. An equation is therefore necessary to assist the designer in this regard. Such an equation should take into account the cross-section shape of the beam and the prestress to reinforcing steel ratios. Many examples would have to be investigated using a rigorous plastic analysis to formulate such an equation. A computer program has been written as part of this thesis to perform such a rigorous analysis. It's accuracy has been evaluated by comparison with laboratory test beam results. The comparison was favourable, although more results would have to be compared to establish the accuracy that could be expected. A few examples were investigated and the observations noted. Two extreme cases were examined, those of a T-beam and I-beam. The redistribution of bending moments was similar in both cases, but the percentage of the central moment capacity reached was considerably less for the T-beam. For both beams it was impossible to reach the ultimate capacity at the centre before the strain capacity at the supports was exhausted. It was concluded that a plastic design procedure should be introduced, based on the ULS capacity of a span at a time. SLS requirements could then be checked afterwards. This approach would provide a design procedure corresponding to those used for other forms of modern structural design and would be much quicker, safer, more accurate and less costly that the existing design procedures. en_ZA
dc.language.iso eng en_ZA
dc.subject.other Prestressed concrete beams - Design and construction en_ZA
dc.subject.other en_ZA
dc.title A new ultimate limit state approach to the design of prestressed concrete beams en_ZA
dc.type Thesis / Dissertation en_ZA
uct.type.publication Research en_ZA
uct.type.resource Thesis en_ZA
dc.publisher.institution University of Cape Town
dc.publisher.faculty Faculty of Engineering & the Built Environment en_ZA
dc.publisher.department Concrete Materials and Structural Integrity Research Unit (CoMSIRU) en_ZA
dc.type.qualificationlevel Masters en_ZA
dc.type.qualificationname MSc (Eng) en_ZA
uct.type.filetype Text
uct.type.filetype Image


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