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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 49 Abstracts search results
Document:
SP209-08
Date:
September 26, 2002
Author(s):
H. M. Nada, D. H. Sanders, M. Saiidi, and S. El-Azazy
Publication:
Symposium Papers
Volume:
209
Abstract:
Past Earthquakes have shown that flared columns are susceptible to pre- mature shear failures. In the 1999 Northridge Earthquake, Shear failures have been caused by a plastic hinge formation occurred at the base of the flare and a subsequent increase in the level of column shear demand above design levels. This paper presents an experimental and analytical study that is examining new details for flared columns and joints. The primary feature is a gap at the top of the column and the amount of transverse flare reinforcement. Two two-column bents were tested on the shake table to examine dynamic effects as well as column and beam interaction. The test specimens had different amounts of confining reinforcement in the flare. The detail proved an overall ductility that is above the minimum limit recommended by the current specifications. Test also showed that gap started to close at ductility level that is below the recommended limit.
DOI:
10.14359/12498
SP209-05
S.M. Alcocer, C. Reyes, D. Bitran, O. Lopez-Batiz, R. Duran-Hernandez, and L. Flores
On June 15, 1999, a magnitude Mw = 7.0 earthquake occurred with epicenter located southwest from the city of Tehuacan, Puebla, and on September 30, 1999, a Mw = 7.5 magnitude earthquake occurred with epicenter located northeast from the city of Puerto Escondido, Oaxaca, Mexico. The earthquakes affected a wide geographical area, including seven states. Few casualties were recorded. In Puebla, 15 percent in the State of Oaxaca and only the remaining ten percent in the States of Morelos, Mexico, Tlaxcala, Veracruz and Guerrero; the second earthquake only affected the State of Oaxaca. Historical buildings, dwellings, hospitals, schools and roads were mostly impacted. Some damages were also experienced in bridges and lifelines. The economic activities were not severely impaired. This paper summarizes the seismological characteristics of the event, its economic impact and the Emergency measures adopted by the authorities. Observation made during several visits to the affected regions of Puebla and Oaxaca on the behavior of soils and foundations, lifeline, schools, dwellings, historical monuments and commercial buildings are described. Recommendations for the development o fvulnerability reduction programs are presented.
10.14359/12495
SP209-06
Y. Lin, J. M. Ingham, and J. W. Butterworth
An experimental investigation was conducted at the University of Auckland to quantify the performance of shear studs embedded in composite ribbed slabs, formed by casting lightweight polystyrene concrete onto profiled steel decking. In total, 18 tests were conducted using a new type of push-off test rig, with test units composed of either lightweight polystyrene concrete or normal weight con- crete (to facilitate performance comparison). This paper reports and discusses the main results of those 18 tests. Results indicated that in most cases designs utilizing lightweight polystyrene concrete had considerable ductility and shear capacity. Recommended design provisions based on the experimental data are presented.
10.14359/12496
SP209-02
G.C. Hoff
An extensive laboratory program was initiated in the early 1980's to develop high-strength lightweight concrete for use in offshore oil and gas structures in severe marine environments. From the results of that development program, four mixtures were chosen to be evaluated under field conditions. Large prisms (305 by 305 by 914mm) of each mixture were placed in the tidal zone at the U.S. Army Corps of Engineers Severe Weather Exposure Station on the border between Canada and the United States. The mixtures used an expanded slate aggregate from the USA and a pelletized clay aggregate from Japan. All mixtures contained silica fume and had total binder content from 494 to 556 kg/cu m with water-binder ratios of 0.28 by mass. The concrete density varied from 1800 to 1990 kg/cu m, with 90-day strength from 60 to 73 MPa depending on the mixture. The prisms under-went annual visual and non-destructive evaluations. After 10-years exposure in the tidal zone, the prisms were removed to the laboratory where they were examined for strength, robustness and chloride ion penetration. This paper reports the results of the test program. In general, the overall performance looks very good.
10.14359/12492
SP209-03
P.K. Mehta
Thermal cracking is a serious problem with modern portland-cement concrete structures, especially cast-in-place massive elements made with relatively high cement content and cured under hot-weather conditions. From theoretical considerations and field experience it is concluded that blended portland-cement concrete mixtures containing 50 percent or more ASTM Class F fly ash by mass of the total cementitious material perform much better under these conditions.
10.14359/12493
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