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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 22 Abstracts search results

Document: 

SP176-06

Date: 

October 1, 1998

Author(s):

M. Saatcioglu, P. Paultre and S.K. Ghosh

Publication:

Symposium Papers

Volume:

176

Abstract:

Synopsis: Recent research on confinement of high-strength concrete (HSC) is reviewed. The emphasis is placed on the effects of confinement parameters and related experimental research. A review of analytical models proposed for HSC is also presented. The results indicate that for similar strength and deformability, HSC requires higher confinement pressure than normal-strength concrete. The level of lateral pressure required can be provided by increasing the volumetric ratio and grade of continement reinforcement. The effkiency of pressure can be improved by reducing the spacing of lateral reinforcement in both the longitudinal and cross-sectional planes. When properly confined, HSC exhibits ductile stress-strain characteristics. The analytical models developed for normal-strength concrete cannot be used to describe stress-strain characteristics of HSC. A number of models have been proposed for HSC that produce good correlations with experimental data.

DOI:

10.14359/5897

Document: 

SP176-07

Date: 

October 1, 1998

Author(s):

C.J. Fasching and C.E. French

Publication:

Symposium Papers

Volume:

176

Abstract:

Flexural behavior of high strength concrete (HSC) beams was investigated based on the experimental work of a number of researchers. The effects of HSC on mechanical properties such as ,modulus of elasticity, tensile strength, limiting concrete compressive strain, and Poisson’s ratio were reviewed. The applicability of current ACI design guidelines and suggested modifications were compared with experimental data in terms of strength, ductility, and serviceability.

DOI:

10.14359/5898

Document: 

SP176-08

Date: 

October 1, 1998

Author(s):

S. Otani and S. Nagai

Publication:

Symposium Papers

Volume:

176

Abstract:

The applicability of methods, routinely used in Japan in evaluating the force-deformation relationship of normal reinforced concrete (RC) members, was examined for high-strength RC beams. The member end moment-rotation relationship was idealized into a trilinear relation with stiffness change at “cracking” and “yielding.” The routine methods overestimate significantly the observed initial stiffness and underestimate yield deformation. A wide scatter is reported in the observed cracking moment. Yield and ultimate resistance can be conservatively estimated by the routine procedure.

DOI:

10.14359/5899

Document: 

SP176-09

Date: 

October 1, 1998

Author(s):

H.J. Pam, H. Tanaka and R. Park

Publication:

Symposium Papers

Volume:

176

Abstract:

A theoretical study was carried out to investigate the effects of increasing concrete strength on the depth of rectangular beams. Two series of beams were investigated. The first series comprised reinforced concrete beams with spans from 6 to 15 m, and the second comprised prestressed concrete beams with spans from 12 to 30 m. The concrete strength ranged from 20 to 120 MPa and from 30 to 120 MPa for the reinforced and prestressed concrete beams, respectively. The results show that for rectangular concrete beams, an increase in concrete strength results in a rather significant reduction in the beam depth, whereas for rectangular prestressed concrete beams no significant reduction in the beam depth is gained from increasing the concrete strength because the deflection governs the design.

DOI:

10.14359/5900

Document: 

SP176-10

Date: 

October 1, 1998

Author(s):

A. Azizinamini and M. Saatcioglu

Publication:

Symposium Papers

Volume:

176

Abstract:

Strength and deformability of High-Strength Concrete (HSC) columns are presented based on recent experimental and analytical research. HSC columns under concentric compression and under combined axial compression and lateral load reversals are discussed. Experimentally observed column strengths are compared with those computed based on the provisions of AC1 3 18 (1) building code and analytical models proposed for HSC columns. The results indicate that the rectangular stress block currently used for normal-strength concrete is not applicable to HSC, especially for columns under high compression where the overall response is dominated by concrete. A triangular and a modified rectangular stress block is presented. Column capacity under concentric compression is illustrated with due considerations given to early spalling of cover concrete. Axial and lateral deformabilities of HSC columns are discussed with emphasis placed on the parameters of confinement. It is shown that HSC columns conforming to the current building code requirements may exhibit ductile behavior under moderate and low levels of axial compression. Higher grade lateral reinforcement can be utilized effectively to confine HSC columns to produce improved inelastic deformability under high levels of axial compression.

DOI:

10.14359/5901

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