International Concrete Abstracts Portal

Showing 1-4 of 4 Abstracts search results

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-M21

Date: 

May 1, 2004

Author(s):

Carlos Videla, Juan Pablo Covarrubias, and Cristian Masana

Publication:

Materials Journal

Volume:

101

Issue:

3

Abstract:

This paper addresses the need to update existing concrete drying-shrinkage prediction models to reflect local materials. The experimental program was carried out using eight concrete mixtures of similar strength, manufactured with portland and portland pozzolan cements representing the most used concretes in Chile. Tests were conducted on 72 specimens and drying strains were measured up to 448 days of drying to investigate the effect of cement type, slump, maximum aggregate size, and specimen dimension on concrete shrinkage. The experimental results were compared with predictions of ACI, CEB, B3, GZ, GL, and Sakata models. All models significantly underestimated the measured shrinkage, particularly for concretes made with cement containing natural pozzolan. Cement type has a significant effect on drying shrinkage time function and magnitude. A procedure was developed to update existing prediction models. Proposed modifications to CEB relationships were derived to predict shrinkage of concrete made with locally available materials.

DOI:

10.14359/13114


Document: 

96-S01

Date: 

January 1, 1999

Author(s):

Patricio Bonelli, Rene Tobar, and Gilberto Leiva

Publication:

Structural Journal

Volume:

96

Issue:

1

Abstract:

The low amount of flexural steel used in the El Faro building in Viña del Mar, Chile, may have caused a brittle failure, leading to its collapse during the earthquake of March 3, 1985. Six 1:10 scale microconcrete models of the most damaged wall of the building were constructed and tested in the laboratory. The study concluded that flexural brittle failure associated with the fracture of the longitudinal reinforcing bars may be prevented by using an appropriate flexural reinforcement ratio. In a second phase, to study the three-dimensional effect of the rest of the structure on the critical wall, a six-story 1:10 scale model of the whole building was constructed and tested under cyclic quasi-static lateral loads. None of the tests reproduced the failure of the actual building. The behavior of the models was characterized by stable hysteresis cycles, with acceptable levels of strength and stiffness degradation. The building model was able to sustain a top displacement of nearly 25 mm (1.5 percent of the height), with extensive cracking and fracturing of longitudinal reinforcing steel, but without catastrophic failure. The real cause of the El Faro building collapse could not be inferred from the available data obtained during this study, leading us to consider the influence of some other effects, such as a possible local weakness of the wall and dynamic effects not considered in this study.

DOI:

10.14359/590


Document: 

JL58-27

Date: 

November 1, 1961

Author(s):

Roger Diaz De Cossio and Emilio Rosenblueth

Publication:

Journal Proceedings

Volume:

58

Issue:

11

Abstract:

Photographic evidence is presented and discussed of different types of failures occurring to reinforced concrete members during earthquakes. For the most part, examples are shown from three recent Mexican earthquakes: the 1956 Oaxaca, the 1957 Mexico City, and the 1959 Coatzacoalcos-Jaltipan. Some examples are also shown from the 1923 Kanto and 1948 Fukui Japanese earth-quakes, and from the recent 1960 Chilean earthquakes. T h e major types of failures observed were shear and diagonal tension, beam or slab-column connection failures, excessive bending, and tension. Most of the damage observed was due to poor construction practices and over-simplifications in the design. However, a study of the photographic evidence makes designers and construction men aware of the major types of damage to guard against. Also, types of failure observed again and again, in different structures and in different regions, point out weaknessesin local building codes.

DOI:

10.14359/7998


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