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: 

SP120-19

Date: 

June 1, 1990

Author(s):

Michael E. Kreger Gregory L. Fenves, and Kamal C. El-Habr

Publication:

Symposium Papers

Volume:

120

Abstract:

A nonlinear finite element analysis was conducted to examine the full range of behavior of segmentally precast box girder construction with external post-tensioning tendons. A primary objective of the study was to examine the effect of dry joints (without epoxy) on the strength and ductility of box girder construction. A secondary consideration was the influence of supplemental bonded internal tendons on the behavior of the structure.

DOI:

10.14359/2859


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


Document: 

SP120-22

Date: 

June 1, 1990

Author(s):

A. S. Nowak, A. E. Naaman, and S. C.Ting

Publication:

Symposium Papers

Volume:

120

Abstract:

Evaluation of existing bridges is an important part of the strategy of dealing with the deteriorating infrastructure. Load and resistance parameters are random variables because of uncertainties in load components, material properties, and dimensions. Therefore, the reliability of a structure is a convenient measure of its performance. The load and resistance models are first summarized. The major load components in bridges are dead load and live load. The live load model is based on the weigh-in-motion studies. Girder distribution factors are derived using special computer procedures for bridge analysis. Behavior of composite girders is considered using a nonlinear model. The basic characteristic of the section is the moment-curvature relationship. The reliability is measured in terms of the reliability index. The approach is demonstrated on evaluation of a prestressed concrete girder bridge. Three cases are considered: original design condition, damaged with corroded strands, and repaired by external prestressing. The load components and load-carrying capacities are evaluated and then the reliability indexes are calculated for the three cases.

DOI:

10.14359/2868


Document: 

SP120-01

Date: 

June 1, 1990

Author(s):

Michel P. Virlogeux

Publication:

Symposium Papers

Volume:

120

Abstract:

The development of external prestressing has been one of the major trends in construction during the last 10 years, along with the development of concrete cable-stayed bridges and the increasing use of high-strength concrete. After a historical review, the main principles of the design of externally prestressed bridges are presented. The paper then details the influence of the construction method on the external tendon organization: bridges built span by span, bridges built by the cantilever method or by methods which are mechanically equivalent, and bridges built by the incremental launching method. Some practical problems are presented, such as handling heavy jacks. A last chapter is devoted to composite structures, with concrete top and bottom slabs and steel webs, prestressed by external tendons. French experimental constructions of this type do not appear economically interesting, and prestressing classical composite structures is not yet considered as good a solution for the same reason. But external prestressing is now widely developed for concrete bridges in the United States, France and, more recently, in Belgium, Switzerland, Venezuela, Germany, and Czechoslovakia.

DOI:

10.14359/3223


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