International Concrete Abstracts Portal

International Concrete Abstracts Portal

The International Concrete Abstracts Portal is an ACI led collaboration with leading technical organizations from within the international concrete industry and offers the most comprehensive collection of published concrete abstracts.

Showing 1-5 of 23 Abstracts search results

Document: 

SP120-15

Date: 

June 1, 1990

Author(s):

Robert J. F. Macgregor, Michael E. Kreger, and John E. Breen

Publication:

Symposium Papers

Volume:

120

Abstract:

An experimental investigation was conducted to examine the service and ultimate load behavior of segmentally precast box girder bridges with external post-tensioning tendons. A primary interest of this study was to examine the effect of joint type (dry versus epoxied joints) on the stiffness, strength, and ductility of the structure. A three-span reduced scale segmental box girder model was constructed, then tested in three stages. Flexural behavior was examined first, then shear tests were conducted on the damaged structure. Test results and observations are presented.

DOI:

10.14359/3277


Document: 

SP120-17

Date: 

June 1, 1990

Author(s):

J. Muller and Y. Gauthier

Publication:

Symposium Papers

Volume:

120

Abstract:

The concept of precast segmental construction with external tendons has been developed extensively since 1978, starting with the construction of the Long Key Bridge (Florida). Since this first experience, many other structures (more than 5,500,000 ftý of deck) have been designed and successfully built using the same method. The performance of all bridges now in operation has been excellent. However, some questions were raised in the minds of engineers, unfamiliar with the method, regarding the behavior of structures prestressed with external tendons beyond the range of design loads (serviceability limit state). Because continuous reinforcement is not usually provided across the match cast joints between segments, concern was expressed that adequate ultimate behavior and sufficient strength could not be obtained. To provide a satisfactory answer to these legitimate questions, a special computer program (DEFLECT) has been developed to analyze accurately the response of the structures prestressed by external tendons. Moreover, several tests are available to confirm the behavior of such structures while verifying the validity of the DEFLECT computer program. This design tool has been used to predict the structural behavior of simply supported and continuous structures beyond joint opening, up to ultimate capacity of the girders with and without thermal loads. Several different prestressing methods have been analyzed with different bonding conditions at the point of deviation of the external tendons. It was found systematically that structures prestressed with either internal or external tendons behave essentially the same way at all loading stages up to ultimate.

DOI:

10.14359/3281


Document: 

SP120-18

Date: 

June 1, 1990

Author(s):

J. EiblI

Publication:

Symposium Papers

Volume:

120

Abstract:

Experience gained in the design of several externally prestressed bridges is reported. New cables especially developed by contractors are discussed. Also, the main experimental results gained at the author's institute for reinforced concrete are given.

DOI:

10.14359/3286


Document: 

SP120-20

Date: 

June 1, 1990

Author(s):

Jeanne M. Nagele, Sankar C. Das, and Reda M. Bakeer

Publication:

Symposium Papers

Volume:

120

Abstract:

The purpose of this investigation was to examine the forces developing in the dome of a prestressed concrete nuclear containment structure due to prestressing of vertical tendons. A computer program was developed for personal computers to evaluate the effect of prestressing forces. A parametric study was conducted, using the program, to examine the effects of dimensions, prestressing force, properties of tendons, etc. on the resulting stresses in the dome.

DOI:

10.14359/2862


Document: 

SP120-21

Date: 

June 1, 1990

Author(s):

Eilhard WoelfelI

Publication:

Symposium Papers

Volume:

120

Abstract:

In the near future, prestressed concrete structures will be designed in Europe according to Eurocode 2 (EC 2). The EC 2 principles governing the design of structures with bonded tendons and with external tendons are given in this paper, and a comparison is made between the structural behavior of the two different types of structures. It is shown that the reliability of both is comparable if the characteristic strain due to prestressing is introduced in the calculations.

DOI:

10.14359/2865


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