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International Concrete Abstracts Portal

Showing 1-5 of 41 Abstracts search results

Document: 

SP93-32

Date: 

September 1, 1986

Author(s):

D. I. Harvey

Publication:

Symposium Papers

Volume:

93

Abstract:

Precast concrete I-girder sections are widely used in bridge construction in British Columbia. A good deal of attention has been paid to methods of splicing girder segments to achieve structural continuity or to extend the span range to which the girders can be applied. A promising development has been the hybrid girder design, whereby pretensioned I-girders are spliced and post-tensioned in the field to achieve con-tinuity. The same technique can be used for precast box-girders which are especially suited to bridges where plan curvature is involved. More structural efficiency and deck durability can be achieved by applying additional post-tensioning after construc-tion of the cast-in-place concrete deck. Four examples of recent bridges using this technique are reviewed, while the limitations and scope for future development are discussed.

DOI:

10.14359/6325


Document: 

SP93-15

Date: 

September 1, 1986

Author(s):

T. I. Campbell and M. S. Mirza

Publication:

Symposium Papers

Volume:

93

Abstract:

A research and development program on prestressed concrete ties for use on open deck railway bridge systems is described. This program involved the design and fabrication of prototype ties, studies of load distribution of a static wheel load among the ties, both by mathematical modelling and laboratory tests on a full-scale bridge system, determination of the strength of individual ties under static and repeated loadings, field testing of bridge systems in service, and a laboratory study of dynamic load distribution in the bridge system. It is shown that three parameters have a significant influence on the distribution of static wheel loads among the ties and that a linear relationship exists between the load taken by a tie and the tie spacing. Laboratory testing for static load distribution showed good correlation with an analyical model, while tests on individual ties indicated adequate strength under static and repeated loadings. Field tests, which are being conducted to determine the loading on individual ties and the behaviour of the ties under railroad traffic, are described and preliminary data are presented.

DOI:

10.14359/6308


Document: 

SP93-30

Date: 

September 1, 1986

Author(s):

H. Ainso and T. M. Tronzo

Publication:

Symposium Papers

Volume:

93

Abstract:

Concrete parking decks are subject to several unique problems which can initiate or aggravate deterioration. These include negative-moment cracking, cold joint cracking, cracking due to embedded conduit runs, and other water related damage. This paper will deal with these problems encountered during the rehabilitation of the parking decks in a 3-story, 28-year-old garage. This structure was not maintained for its entire life, except for the installation of a waterproofing membrane on the top deck about 8 years ago. The topics covered are: 1) inspection and testing what to look for and specific test procedures; 2) causes and recommendations for the repair of some of the problems encountered.

DOI:

10.14359/6323


Document: 

SP93-12

Date: 

September 1, 1986

Author(s):

B. Shackel

Publication:

Symposium Papers

Volume:

93

Abstract:

This paper describes the development of two computer-based procedures for the design of industrial pavements subject to heavy, off-road vehicles such as forklift and straddle carriers. The procedures model the subgrade as either a Winkler or a Boussinesq material. In either case, the methodology eschews the use of the equivalent wheel load concepts that have, hithertoo, formed the basis of most design methods for industrial pavements. Rather the programs seek to model realistically the wide spectrum of axle loads and axle configurations common in industrial applications. Such modelling requires large numbers of design calculations. For this reason the programs utilise methods of aralysiswhich have been developed to yield very compact computer code so that computation may be completed rapidly. This has the added benefit that the programs can run on relatively small computers including microcomputers. The programs are suited to the design of the jointed concrete pavements and of continuous pavements such as those formed from roller compacted concrete.

DOI:

10.14359/6305


Document: 

SP93-28

Date: 

September 1, 1986

Author(s):

N. P. Bada

Publication:

Symposium Papers

Volume:

93

Abstract:

Several of the bridge non air-entrained concrete bearing seats on the International Control Dam have concrete deterioration from the application of de-icing salts. A 410 tonne beam and deck slab assembly was raised by twelve hydraulic lift climbing jacks assembled to a single span Bailey Bridge Structure. The concrete repair consisted of removing the deteriorated concrete, application of an epoxy bonder, wood forming, and placing of good quality concrete. The 410 tonne beam and deck slab was lowered onto new elastomeric bearing pads to its original location. The paper details the construction procedures and methods of repair to concrete in Spans 2 and 4.

DOI:

10.14359/6321


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