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Home > Publications > 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
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
SP117-04
M. M. Elnimeiri and M. R. Joglekar
Differential elastic, creep, shrinkage, and thermal deformations of vertical concrete elements, columns, and walls in tall building structures require special attention to insure proper behavior for both strength and serviceability of the structure and the attached nonstructural elements. The long-term serviceability problems include out-of-level floors in both concrete and composite buildings, and cracking and deformations of internal partitions and external cladding elements. A procedure is developed to predict the long-term deformations of reinforced concrete columns, walls, and composite columns. The procedure incorporates the effects of concrete properties, construction sequence, and loading history. For composite columns, the effects of load transfer from the steel erection column to the reinforced concrete column are also included. Methods to minimize differential shortening of columns and walls are discussed. The methods involve corrections during both design and construction phases. Differential shortening effects for three tall buildings, in Chicago, which were designed using the procedure, are discussed. Results from six years of field measurements of column shortening are compared with predicted values.
10.14359/3318
SP117-09
M. K. Tadros,A. Yousef, and Y. S Joo
Deals primarily with statically indeterminate beams where settlement of the supports can produce stresses. A method of estimating the effects of support settlement is presented. The method accounts for the fact that soil consolidation and the corresponding support settlement often develop over an extended period of time. The method also demonstrates that creep of concrete can reduce the ultimate settlement-induced stresses in uncracked members by as much as 60 percent of the elastic values. Furthermore, flexural cracking of concrete results in reduction of the member stiffness. This corresponds to further relief of the settlement-induced stresses. Field studies on the effects of settlement in several bridges are presented. The relationship between the amount of settlement and its structural effects is illustrated.
10.14359/2824
SP117-10
U. Ersoy and T. Tankut
Two case studies are presented as examples illustrating the problem of shrinkage in reinforced concrete buildings in Central Turkey, where humidity is quite low and extreme temperature changes take place. The first case discussed is a structure consisting of one-bay frames with curved beams spanning 36 m. Axial tension created by shrinkage had reduced the axial thrust in the beams causing a considerable drop in the flexural capacity and leading to severe cracking. The second case presented is a grain bin where vertical cracks in the silo walls were explained mainly by the restraining effect of the rigid foundation against shrinkage deformations. Types and causes of shrinkage cracks are discussed, and the methods of analysis used are briefly explained for each case. The estimated values of shrinkage deformations in dry climates with extreme temperature changes are compared with experimental values, and some serious possible consequences are explained.
10.14359/2830
SP117-12
M. R. Resheidat
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.
10.14359/2837
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