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http://hdl.handle.net/2440/12
2015-05-30T02:27:33ZPresliding shear failure in prestressed RC beams. II: behavior
http://hdl.handle.net/2440/91401
Title: Presliding shear failure in prestressed RC beams. II: behavior
Author: Zhang, T.; Visintin, P.; Oehlers, D.J.; Griffith, M.C.
Abstract: Abstract not available2013-12-31T13:30:00ZPresliding shear failure in prestressed RC beams. I: partial-interaction mechanism
http://hdl.handle.net/2440/91400
Title: Presliding shear failure in prestressed RC beams. I: partial-interaction mechanism
Author: Zhang, T.; Visintin, P.; Oehlers, D.J.; Griffith, M.C.
Abstract: Abstract not available2013-12-31T13:30:00ZAnalysis of shrinkage in prestressed concrete slabs and beams
http://hdl.handle.net/2440/91379
Title: Analysis of shrinkage in prestressed concrete slabs and beams
Author: Warner, R.F.
Abstract: A step-by-step method of analysis is used in this paper to study the long-term effects of shrinkage in prestressed concrete members, and in particular shrinkage warping and loss of prestress. The step-by-step method is also being used in a parallel study of creep in prestressed concrete beams. A simple, closed-form equation is derived for the long-term shrinkage curvature in the cross-section of a rectangular prestressed member that contains tensile and compressive reinforcing steel. This allows the shrinkage deflection of the member to be calculated by first evaluating curvatures at key sections and then integrating. A simple, closed-form equation is also derived for the long-term loss of prestress due to shrinkage. Numerical studies show that tensile and compressive reinforcement strongly influence both the curvature and the prestress loss due to shrinkage. An assumption made in the analyses is that shrinkage occurs uniformly throughout the concrete. This is the basis of the current AS 3600 shrinkage clauses, and hence also of most current shrinkage design calculations. In reality, shrinkage in concrete members is non-uniform and non-linear. The paper concludes with a discussion of non-uniform shrinkage, and gives an outline of how the step-by-step method can be used to analyse non-uniform shrinkage.2013-12-31T13:30:00ZCreep in prestressed concrete beams under time-varying sustained loading
http://hdl.handle.net/2440/91378
Title: Creep in prestressed concrete beams under time-varying sustained loading
Author: Warner, R.F.
Abstract: In the design of prestressed concrete flexural members it is necessary to allow for the long-term effects of creep and shrinkage, particularly in regard to deflections and prestress loss. Various analytic methods can be used to evaluate these long-term effects, but the calculations for creep become extended and complex if, as is usually the case, the sustained load on the member varies over time. In this study a simplified, approximate method is proposed for dealing with creep under a varying load history. The time-varying moment history in the cross-section of a member is replaced by a constant, sustained, “equivalent” moment, Meq, which has the same long-term effect as the time-varying moment. This equivalent moment can be used together with any appropriate constant-moment creep analysis, but is here combined with previously-derived, closed-form expressions for loss of prestress and creep curvature. The result is a simple procedure for dealing with creep in prestressed members under time- varying sustained loads.2013-12-31T13:30:00Z