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International Concrete Abstracts Portal

Showing 1-5 of 42 Abstracts search results

Document: 

13-073

Date: 

September 1, 2014

Author(s):

Sungjin Bae

Publication:

Structural Journal

Volume:

111

Issue:

5

Abstract:

Consideration of temperature effects is important for designing concrete structures such as chimneys, nuclear structures, and liquefied gas containments. Internal stresses due to temperature changes need to be estimated and accounted in design loads or design strengths. These internal stresses vary with cracking of concrete, yielding of reinforcement, and restraint conditions and, thus, accurate estimates of internal stresses due to temperature changes involve complicated analysis procedures. Due to the complexity of the problem, ACI 307-08, ACI 349-06, and ACI 359-10 have developed different design approaches for temperature effects. The objective of this study is to examine these design approaches and evaluate their performance on estimating thermal effects. The influence of axial forces on thermal effects is discussed, and recommendations are made.

DOI:

10.14359/51686818


Document: 

102-S34

Date: 

May 1, 2005

Author(s):

Victor I. Fernandez-Davila, Rodrigo A. Dunner, and Leonardo E. Carrion

Publication:

Structural Journal

Volume:

102

Issue:

3

Abstract:

This paper describes a simplified method for seismic analysis and design of industrial chimneys that allows an accurate estimation of the fundamental period of vibration, lateral displacements, shear forces, and bending moments through a set of equations, with errors obtained below 10% for all cases studied. During the initial stage of the analysis, it was verified that the criterion of consistent mass yields better results than the criterion of lumped mass, and that a finite element model with 20 beam sectors is satisfactory. The acceleration spectrums recommended by the new code of seismic design for structures and industrial installations in Chile have been considered to define the earthquake loading. Modal responses were combined using the complete quadratic combination rule. In all of the cases studied in this investigation, the influence of the P-D effect of the soil-structure interaction and the influence on the response of the lining have been disregarded.

DOI:

10.14359/14405


Document: 

101-S35

Date: 

May 1, 2004

Author(s):

Amir M. Horr, Mohammad Safi, and Naser Asadpour

Publication:

Structural Journal

Volume:

101

Issue:

3

Abstract:

The conventional finite element method has been used successfully in linear and nonlinear analyses in concrete chimney structures. The method can be performed by subdividing the large structure into small uniform elements having approximate shape functions. Although this replaces a single complicated structural system into a number of simple uniform elements, in cases of tall concrete chimney structures with cracking and crushing behavior in concrete material and yielding in the reinforcement, the computer time and memory can be large. Hence, it is desirable to search for a procedure requiring a fewer number of elements and also less computer time and effort to model a structure. In this respect, attention is paid to the advanced complex damped spectral element method, which benefits from the more accurate and also mathematically complicated shape functions. The use of advanced spectral element method can help engineers design a complex structure, like a tall concrete tower, with a lower cost and weight. Using a computer program, the proposed formulation has been used to derive the nonlinear dynamic response of a tall concrete chimney.

DOI:

10.14359/13094


Document: 

100-S39

Date: 

May 1, 2003

Author(s):

Sami A. Kilic and Mete A. Sozen

Publication:

Structural Journal

Volume:

100

Issue:

3

Abstract:

Two tall reinforced concrete chimneys, Stacks 25F-5 (115 m) and 36F-5 (107.5 m), were subjected to strong ground motion during the August 17, 1999, Marmara earthquake. Stack 25F-5 failed while Stack 36F-5 survived. Both stacks were designed in accordance with ACI 307-69. This study reports the earthquake parameters, the ground motion measured within 3 km of the stacks, and the structural properties of the stacks. Evaluation of the response bounds of the stacks leads to the conclusion that the region of flexural yielding remained at the base of Stack 36F-5 while it was at a level approximately 35 m above base for Stack 25F-5 because it had a large penetration extending from 30 to 35 m. The collapse of Stack 25F-5 was not due to lack of strength caused by design or material deficiencies but was due to the presence of reinforcing-bar splices in the region where flexural yielding occurred.

DOI:

10.14359/12611


Document: 

99-S64

Date: 

September 1, 2002

Author(s):

John L. Wilson

Publication:

Structural Journal

Volume:

99

Issue:

5

Abstract:

A lack of experimental data related to the cyclic behavior of chimney structures to severe earthquake ground shaking has resulted in design standards generally ignoring the effects of ductility and adopting conservative aseismic design provisions. This paper presents results from an experimental study that demonstrates that correctly detailed reinforced-concrete chimney sections are not brittle but possess some ductility. The experimental results have been used to develop a nonlinear dynamic analysis procedure for evaluating the inelastic response of tall reinforced-concrete chimney structures. The procedure is used to study the seismic response of ten chimneys, ranging in height from 115 to 301 m. Based on the nonlinear dynamic study, a series of code design recommendations has been developed and incorporated into the 2001 CICIND code to reduce the seismic loads by a factor of R = 2 by detailing for ductility and preventing the formation of brittle failure modes. The 2001 CICIND design recommendations result in both improved performance and cost savings of up to 20% compared with existing design practices.

DOI:

10.14359/12302


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