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ACI318-09

ACI Committee 318, 2015

Building Code Requirements for Structural Concrete ACI318M-14

PCI Journal

Committee members voting on the 1992 revisions are listed on p. 517.2R-17 Accelerated curing of concrete is used extensivly in lhe production of precast concrete structural members, pipe, masonry units, and presíressedproducts. Steam curing isprobably the mosi widely used meíhod at the present time. Recent modi6 cations and changes in this method are discussed, as wellas effectof the curing cycles In addition to steam curing, the effect of variaiions in the concrete materials on accelerated curing is discussed, as are special cements and accelerators. Special treatments, including carbonation, accelerated drying, and heating prior to molding , are also cover& frared heating, are discussed.

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Radomir Folić 1 Boris Folić 2 Miloš Čokić UDK: 624.078:624.042.7 DOI: 10.14415/konferencijaGFS2021.03 Summary: The paper presents the provisions of the Standards that regulate the methods of the analysis and detailing of joints and connections of structural elements. Norms are covered in ACI 318, Eurocode 2 and 8, Code New Zealand, fib Model Code 2010 (2013), and their bulletins. Analyses and shaping of connections according to the mentioned norms and literature depending on the stress states to which the elements are exposed are presented. The recommendations of individual international associations were also analysed in PCI Design Handbook Precast and Prestressed concrete, ACI C 533 Guide Precast concrete, Guidelines for the use of Structural Precast Concrete (New Zealand). For some connections (loops) and other analyses, based on recent studies of their behaviour under load that simulate seismic actions, approximate analyses are also presented.

The following thesis presents the results of four full scale beams tests as part of a research program conducted at McGill University. The purpose is to study the applicability of existing design provisions, in the American Association of State Highway and Transportation Officials (AASHTO) specifications, for the use of self-consolidating concrete (SCC) in precast pretensioned bridge girders.The test specimens had an overall length of 31 ft (9.4m) with a center-to-center span of 29 ft (8.8m). They were cast in four batches with different concrete attributes: two non air-entrained SCC mixtures and two high-performance concretes. For each type, compressive strengths of 8,000 and 10,000 psi (55.2 and 69 MPa) with release strengths of 5,000 and 6,250 psi (34.5 and 43 MPa) at 18 hours, respectively, were tested. Each girder was prestressed with eight Grade 270 seven-wire low-relaxation prestressing strands of 0.6 in (15.2 mm) diameter. Six of the strands were straight and two were harped twice, 4’-11” (1.5 m) from mid-span. The specimens were supported on neoprene bearing pads at their ends, and were tested with two equal point loads located 4’-11” (1.5 m) from mid-span.This research project demonstrated that the shear failure of the girders exceeded the predicted nominal shear resistance given by the 2004 AASHTO Specifications. The experimental flexural resistance also exceeded the predicted nominal resistance.

BONDED AND UNBONDED POST- TENSIONING TECHNOLOGIES, 2020

Education Sciences

Educational approaches in structural engineering have focused on classical methods for solving problems with manual calculations through assignments, quizzes, and exams. The use of computational software to apply the learned knowledge has been ignored for decades. This paper describes an educational approach to tackle the lack of applicable practical exercises in the structural engineering class “CE 506-Prestressed Concrete” at a university in the western United States during the spring of 2017. The class was designed to provide students with the theoretical concepts of prestressed concrete and the ability to interpret applicable design codes. In their project, students continued to build this knowledge by designing a prestressed bridge superstructure according to a unique state design manual. Students prepared a literature review of their selected state in the U.S.A. and used commercial software to perform an analysis and design of their bridge. Additionally, students were asked to...