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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 91 Abstracts search results
Document:
SP128-60
Date:
November 1, 1991
Author(s):
A. K. Ahuja, S. K. Pathak, and S. A. Mir
Publication:
Symposium Papers
Volume:
128
Abstract:
The wind tunnel tests were carried out on rigid models of tall buildings with square plan shape to study the effects of interference on wind loads on tall buildings. This paper presents the results of the same. Effects of various geometric and flow parameters on total force and moments are reported, which are deduced from the wind pressure values obtained on isolated instrumented buildings in the vicinity.
DOI:
10.14359/2892
SP128-65
Hitoyuki Takagi and Yoshikazu Kanoh
In this paper, the effect of high-strength bars in web reinforcement is evaluated based on the test results in Japan. Discussions have centered on the effect on members' shear strength and reinforcement performance for splitting bond failure along longitudinal reinforcements. High-strength bars with a yield strength of 80,000 to 130,000 N/cm3 proved to be very effective in increasing the shear strength of members, especially for high-strength concrete. However, high-strength bars were no more effective than normal strength bars in preventing splitting bond failure. Formulas were derived for normal and high-strength bars to predict the ultimate shear force at shear failure as well as splitting bond failure in members.
10.14359/2897
SP128-61
B. H. Oh, H. J. Lee, D. H. Lim, and S. K. Lee
Presents a study on the flexural behavior of reinforced concrete beams containing steel fibers. Several series of reinforced concrete beams have been tested. The present test program includes two series of singly reinforced concrete beams and one series of doubly reinforced concrete beams. The fiber contents for each series were varied from 0 to 2 percent by volume. The load was applied in flexure at the third-points. The deflections at the center- and quarter-points of the beam were measured, and the strains of concrete and steel at various points were also measured and automatically stored in the computer. The crack widths and crack spacings at each loading step were observed during the incremental loading process. The load-deflection curves were generated from the measured data. The present tests show that the crack widths increase almost linearly with the increase of steel stress and that the crack widths at the same loading steps are remarkably reduced as the fiber amounts increase. Fiber addition was found to improve considerably the ductility and load-carrying capacity of reinforced concrete members.
10.14359/2901
SP128-64
T. AmirsoleymaniI
The largest sports stadium of Iran consisting of 36 concrete cells was completed in 1974. As extensive cracks formed in the beams and walls, the repair work on concrete and post-tensioning of the beams were undertaken. After a few years, propagation of cracks was observed in most of the tapered cantilever beams. The re-evaluation of structural analysis and material tests showed that formation of horizontal cracks could be attributed to discontinuities in the materials such as dowels or sharp intrusion at the surface. In all of the tapered cantilever beams, the longitudinal reinforced bars were one-half to one-third of the required amount given in ACI 318-83. The actual load had been more than initial design load on numerous occasions throughout the last 15 years without resulting in total failure. Therefore, it is recommended to re-evaluate the minimum requirement for longitudinal reinforcement bars and to consider the use of balanced torsional stiffness for tapered cantilever beams under intensive torsion.
10.14359/2909
SP128-66
K. Yoshimura, K. Kikcuri, and M. Kuroki
There are quite a large number of existing reinforced concrete (RC) short columns which are expected to fail in brittle shear failure mode during severe earthquakes. To develop an effective seismic shear strengthening method for improving the earthquake behavior of these reinforced concrete short columns, experimental studies are conducted by using six different 1/3-scale beam-column subassemblage specimens with a short column. Three short columns of these specimens are strengthened by steel plates, while another three are without any steel plate strengthening. All the specimens are tested under a constant gravity load and alternately repeated lateral forces. Test results demonstrate that, if the short column is strengthened by a welded steel square tube, then brittle shear failure does not occur and the column can develop its ultimate flexural moment capacity. It is also shown by additional tests that the proposed strengthening method using steel plates is applicable to repair and rehabilitate the damaged short columns that failed in the brittle shear mode. Finally, an application example of the proposed strengthening method to the actual existing short columns is presented.
10.14359/2922
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