Serviceability Criteria for Decompression in Prestressed Concrete Bridge Girders
Author: Piotr Paczkowski
Publisher:
Published: 2009
Total Pages:
ISBN-13: 9781109085532
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Author: Piotr Paczkowski
Publisher:
Published: 2009
Total Pages:
ISBN-13: 9781109085532
DOWNLOAD EBOOKAuthor: Hassan Hassan El-Hor
Publisher:
Published: 1995
Total Pages: 474
ISBN-13:
DOWNLOAD EBOOKAuthor: Maher K. Tadros
Publisher: Transportation Research Board
Published: 2010
Total Pages: 76
ISBN-13: 0309118352
DOWNLOAD EBOOKThis report establishes a user's manual for the acceptance, repair, or rejection of precast/prestressed concrete girders with longitudinal web cracking. The report also proposes revisions to the AASHTO LRFD Bridge Design Specifications and provides recommendations to develop improved crack control reinforcement details for use in new girders. The material in this report will be of immediate interest to bridge engineers.
Author: Paul Barr
Publisher:
Published: 2010
Total Pages: 244
ISBN-13:
DOWNLOAD EBOOKThe design procedure to calculate the shear capacity of bridge girders that was used forty years ago is very different than those procedures that are recommended in the current AASHTO LRFD Specifications. As a result, many bridge girders that were built forty years ago do not meet current design standards, and in some cases warrant replacement due to insufficient calculated shear capacity. However despite this insufficient calculated capacity, these bridge girders have been found to function adequately in service with minimal signs of distress. The objective of this research was to investigate the actual in service capacity of prestressed concrete girders that have been in service over an extended period of time.
Author: Maher K. Tadros
Publisher: Transportation Research Board
Published: 2003
Total Pages: 73
ISBN-13: 030908766X
DOWNLOAD EBOOK"The HCM includes three printed volumes (Volumes 1-3) that can be purchased from the Transportation Research Board in print and electronic formats. Volume 4 is a free online resource that supports the rest of the manual. It includes: Supplemental chapters 25-38, providing additional details of the methodologies described in the Volume 1-3 chapters, example problems, and other resources; A technical reference library providing access to a significant portion of the research supporting HCM methods; Two applications guides demonstrating how the HCM can be applied to planning-level analysis and a variety of traffic operations applications; Interpretations, updates, and errata for the HCM (as they are developed);A discussion forum allowing HCM users to ask questions and collaborate on HCM-related matters; and Notifications of chapter updates, active discussions, and more via an optional e-mail notification feature."--Publisher.
Author: Makoto Yanaka
Publisher:
Published: 2004
Total Pages: 544
ISBN-13:
DOWNLOAD EBOOKAuthor: César Crespo Minguillón
Publisher:
Published: 1996
Total Pages:
ISBN-13:
DOWNLOAD EBOOKAuthor: Jessica Lauren Salazar
Publisher:
Published: 2016
Total Pages: 352
ISBN-13:
DOWNLOAD EBOOKPretensioned concrete girders are currently fabricated using 0.5- or 0.6-in. diameter prestressing strands. In recent years, however, it has become of interest to employ larger-diameter 0.7-in. diameter strands to reduce the number of strands and improve the efficiency of pretensioned concrete members. Such a transition requires a considerable initial investment that needs to be justified based on the benefits obtained. Furthermore, the use of 0.7-in. strands would increase the stresses within the end-region of pretensioned elements, which could lead to undesirable cracking and impact the serviceability of the girders. The work presented in this thesis consists of 1) a comprehensive parametric investigation to evaluate the benefits and limitations of using 0.7-in. strands in pretensioned bridge girders, and 2) a full-scale experimental study to investigate the behavior of pretensioned concrete girders with 0.7-in. strands at the time of prestress transfer. The parametric investigation was accomplished by designing thousands of bridge girders with different span lengths, concrete release strengths, and transverse spacings. The results showed that the most noticeable benefit of 0.7-in. strands over 0.6-in. strands was a reduction of up to 35 percent in the number of strands. However, the difference in the total weight of prestressing steel was insignificant. Increasing the release strength of concrete, at least to 7.5 ksi, was found essential to observe benefits in design aspects other than the number of strands. The experimental investigation involved the fabrication of two Tx46 and two Tx70 specimens at the Ferguson Structural Engineering Laboratory. All specimens employed 0.7-in. strands on a 2- by 2-in. grid and the standard detailing currently used for girders with smaller-diameter strands. The observed crack widths in the specimens upon prestress transfer did not exceed those typically observed in Tx-girders with smaller-diameter strands. Therefore, the use of 0.7-in. strands does not seem to trigger a need to modify the end-region detailing in Tx-girders. However, noticeably greater bursting and spalling forces were observed in the end regions of the specimens compared to the demands predicted by AASHTO LRFD provisions. The measured 24-hour transfer length from the specimens also exceeded estimates by AASHTO LRFD and ACI 318-14 provisions.
Author: C. Yilmaz
Publisher: Springer Science & Business Media
Published: 2012-12-06
Total Pages: 447
ISBN-13: 9400961227
DOWNLOAD EBOOKThe Proceedings of the NATO Advanced Study Institute on Analysis and Design of Bridges held at ~e§me, lzmir, Turkey from 28 June 1982 to 9 July 1982 are contained in the present volume. The Advanced Study Institute was attended by 37 lecturers and participants from 10 different countries. The Organizing Committee consisted of Professors P. Gtilkan, A. C. Scordelis, S. T. Wasti and 9. Yl. lmaz. The guidelines set by NATO for the Advanced Study Institute require it to serve not only as an efficient forum for the dissemination of available advanced knowledge to a selected group of qualified people but also as a platform for the exploration of future research possibilities in the scientific or engineering areas concerned. The main topics covered by the present Advanced Study Institute were the mathematical modelling of bridges for better analysis and the scientific assessment of bridge behaviour for the introduction of improved design procedures. It has been our observation that as a result of the range and depth of the lectures presented and the many informal discussions that took place, ideas became fissile, the stimulus never flagged and many gaps in the engineering knowledge of the participants were "bridged". Here we particularly wish to mention that valuable informal presenta tions of research work were made during the course of the Institute by Drs. Friedrich, Karaesmen, Lamas and Parker.
Author: G.C. Koukis
Publisher: CRC Press
Published: 1997-01-01
Total Pages: 366
ISBN-13: 9789058091970
DOWNLOAD EBOOKComposed of the proceedings of a symposium on engineering geology and the environment, held in Athens in June, 1997, this work provides a survey of trends in engineering geology, and an interdisciplinary collaboration with hydrogeology, geochemistry, geomorphology, and soil and rock mechanics.