International Concrete Abstracts Portal

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 63 Abstracts search results

Document: 

SP193-31

Date: 

August 1, 2000

Author(s):

M. Imam and L. Vandewalle

Publication:

Symposium Papers

Volume:

193

Abstract:

The paper investigates the shear strength and the failure modes of high strength concrete beams with and without steel fibers ( fC = 110 MPa). Sixteen reinforced high strength concrete beams (3600x350~200 mm) were tested under different combinations of shear force and bending moment. The beams were singly reinforced and without shear (web) reinforcement. The test results indicated that the addition of steel fibers to high strength concrete increases the ultimate shear strength, improves the brittle characteristic and transforms the failure mode into a more ductile one. The average gain of the ultimate shear strength due to the addition of steel fibers varied from about 14% to 14 1% depending on the shear span to depth ratio and the longitudinal steel ratio. Four modes of failure of reinforced high strength concrete are clearly distinguished as; diagonal tension, shear compression, shear flexure, and flexural failure. In general, cracks in fiber reinforced concrete beams are closer, narrower, and more than those in beams without fibers. This reflects the effect of steel fibers in redistributing the stresses beyond cracking.

DOI:

10.14359/5841


Document: 

SP193

Date: 

August 1, 2000

Author(s):

Editor: V.M. Malhotra

Publication:

Symposium Papers

Volume:

193

Abstract:

In September 2000, the American Concrete Institute sponsored the ACI Fourth International Conference in Seoul, Korea. Sixty-two papers are included in this publication. Note: The individual papers are also available as .pdf downloads.. Please click on the following link to view the papers available, or call 248.848.3800 to order. SP193

DOI:

10.14359/14227


Document: 

SP193-36

Date: 

August 1, 2000

Author(s):

H. Hamada, T. Yamaji, K. Hayakawa, and H. Yamashita

Publication:

Symposium Papers

Volume:

193

Abstract:

In this study, two types of optical fiber sensors attached on the concrete surface, called a Straight-type sensor and Loop-type sensor were developed. Through bending tests of RC beam specimens, detailed data on beam deflection and optical performance of attached fiber were collected. Overall performance of the optical fiber sensor as a concrete performance monitor is discussed. Test procedures, test results and their discussions are summarized. Based on the experimental result, several conclusions were obtained. 1) The adhesion of epoxy resin to concrete surface is not lost until ultimate concrete failure. 2) The sensitivity of the Straight-type sensor is affected by the angle of concrete cracking and optical fiber intersection. 3) The distance between cracking location and looped circle of optical fiber affects the sensitivity of the Loop-type sensor. 4) Both for the straight type and the loop type, in order to develop a satisfactory level sensor, further research is strongly recommended.

DOI:

10.14359/9948


Document: 

SP193-37

Date: 

August 1, 2000

Author(s):

H. Nakai, N. Wada, N. Suzuki, and Y. Fujiwara

Publication:

Symposium Papers

Volume:

193

Abstract:

In the aftermath of the Great Hanshin-Awaji Earthquake of 1995, the seismic retrofitting of existing structures has been implemented on a nation-wide basis throughout Japan, and it is in this context that new methods for seismic retrofitting utilizing aramid fiber reinforced plastic rod have been developed. Aramid fiber rod is not only lightweight and flexible, but has superior strength and corrosion resistance characteristics, which make it an ideal material for use in the seismic retrofitting of reinforced concrete structures. AWS method involves the use of aramid fiber rods to introduce prestress into wall-type piers, again improving the ductility and shear strength of the existing wall. Testing of scale models gave results showing this method to provide sufficient strength. The guidelines available for retrofitting of highway bridge piers in Japan are presented. The design equations for ultimate shear strength and ductility of retrofitted RC structures are introduced. AWS method is now used in the seismic retrofitting wall-type piers of highway bridges.

DOI:

10.14359/9949


Document: 

SP193-38

Date: 

August 1, 2000

Author(s):

T. Kamada, T. Kawase, M. Kunieda, and K. Rokugo

Publication:

Symposium Papers

Volume:

193

Abstract:

This paper describes a nondestructive method to evaluate two-dimensional size and depth of interfacial flaws between concrete members and the enclosing steel plate by the infrared thermographic technique. In this procedure, in order to investigate the influence of a defect in a thermography, liquid nitrogen was used to cool the surface of the steel plate. Its thermal distribution was measured. From these measurements, it was possible to estimate the diameter of circular defects from the calculated inflection points in the thermal distribution curve. The process to evaluate the depth of the flaws by using the relation betweenthe volume tof the flaws and proposed thermal parameters is also presented.

DOI:

10.14359/9950


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