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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 14 Abstracts search results

Document: 

SP117-13

Date: 

October 1, 1989

Author(s):

C. J. Hookham and T. L. Bailey

Publication:

Symposium Papers

Volume:

117

Abstract:

Long-term durability of reinforced and prestressed concrete structures in U.S. nuclear power plants was identified as a critical issue in the feasibility studies of plant life extension. Evaluation of concrete structures at several operating plants included studies of known concrete degradation modes, performance of condition surveys/testing, and service life prediction. Results indicate that service lives of 60 or more years are achievable, provided that preservation activities are conducted for these concrete structures.

DOI:

10.14359/2843

Document: 

SP117-11

Date: 

October 1, 1989

Author(s):

P. Arumugasaamy and R. N. Swamy

Publication:

Symposium Papers

Volume:

117

Abstract:

Presents a simple design aid for predicting long-term (up to 50 years) movements in reinforced concrete columns and bridge beams made of normal and lightweight aggregate concrete. The method is based on the principle of superposition using a creep factor chart, which takes into account varying sizes of members, age at loading, exposure conditions, and the percentage of reinforcement, and it requires only a knowledge of the concrete strength and the loading history of the member. The method is developed from the study of in situ movements in two reinforced concrete structures subjected to increment loading. The shrinkage strains in columns are predicted using a shrinkage chart, which requires only a knowledge of elastic modulus of concrete at 28 days. The predicted load-induced and basic strains show excellent agreement with measured strains in the two structures, and the method shows good agreement with literature. The paper demonstrates how the simple method of predicting long-term movements in buildings and bridges can be utilized by the structural engineer as a designer's tool.

DOI:

10.14359/3165

Document: 

SP117-03

Date: 

October 1, 1989

Author(s):

S. Ikeda

Publication:

Symposium Papers

Volume:

117

Abstract:

In seismic zones, severe earthquakes occur within a certain period. However, the important functions of a concrete structure must be maintained after the earthquake. Hence, structures must be designed for safety during the earthquake and serviceability after the earthquake. The acceptable level of damage can be varied in accordance with the type and importance of the structure. When a reinforced concrete structure suffers significant plastic deformation, residual deformation and large crack opening in the structure are impaired. A new and rational seismic design method was proposed. The peculiarity of the concept of the design method is as follows: Seismic design should be performed to fulfill required serviceability after the design earthquake as well as required safety during the earthquake. High magnification factor due to dynamic response was introduced according to actual observation in the earthquakes. Reduction factor referred to the acceptable level of damages in the structure after the earthquake was introduced. The importance of design details was emphasized. Furthermore, the influence of axial compressive force on the ductility was pointed out.

DOI:

10.14359/3171

Document: 

SP117

Date: 

October 1, 1989

Author(s):

Editor: Anis Farah

Publication:

Symposium Papers

Volume:

117

Abstract:

SP-117 If you are a structural engineer or a contractor, this important new volume will enhance your understanding of the most up-to-date data and techniques for assessing the long-term serviceability of new and existing concrete structures.

DOI:

10.14359/14150

Document: 

SP117-12

Date: 

October 1, 1989

Author(s):

M. R. Resheidat

Publication:

Symposium Papers

Volume:

117

Abstract:

Internal algorithms for creep and shrinkage when substituted by approximate algebraic equations lead to the adoption of a computational procedure substantially independent of linear equations adopted in the time-dependent prediction model. Presented herein are the numerical results of stresses and strains of reinforced and post-tensioned concrete bridge box-sections where creep and shrinkage are considered. Field measurements of deformations have been recorded and compared with the corresponding numerical results obtained by utilizing a computer program. Results are presented in a graphical form. It may be concluded that the computer method is a convenient tool for describing the behavior of structural concrete sections considering creep and shrinkage in connection with performance and service ability.

DOI:

10.14359/2837

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