ABOUT THE 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.

International Concrete Abstracts Portal

Showing 1-5 of 13 Abstracts search results

Document: 

SP161-08

Date: 

April 1, 1996

Author(s):

M. A. Bhatti, B. Lin, and J. P. Idelin Molinas Vega

Publication:

Symposium Papers

Volume:

161

Abstract:

The usual design practice for analysis of reinforced concrete slabs with openings is to neglect holes if their area is less than 10- 12% of the total slab area. This practice is based in part on studies conducted in early sixties regarding the effects of holes on the elastic behavior of plates. A literature survey revealed no specific studies regarding the effects of holes on deflection and strength of reinforced concrete slabs with openings. This paper presents a numerical study of the effects of openings of different sizes on the behavior of reinforced concrete slabs. A nonlinear finite element model for reinforced concrete slabs is developed using three dimensional brick elements taking into account cracking and crushing of concrete, and plasticity of both reinforcement and concrete. Distributed and concentrated loads are applied to slabs until collapse. Results show that when slabs are subjected to uniformly distributed loads, the openings do not have much effect on their strength and serviceability. The openings should be considered, however, when designing slabs subjected to concentrated loading where the opening ratios are larger than 2.5% .

DOI:

10.14359/10055


Document: 

SP161-07

Date: 

April 1, 1996

Author(s):

B. Chen and E. G. Nawy

Publication:

Symposium Papers

Volume:

161

Abstract:

Use of prestressed prisms as main reinforcement has been demonstrated to be effective in limiting cracks and reducing deflections in high-strength, high performance concrete beams. To further understand the load-deformation history of such type of structural members, computer-simulated analysis has been conducted. A nonlinear analytical model based on strain compatibility was established. Theoretical predictions are compared with the experimental data obtained by the authors. Comprehensive computer-simulated flexural tests were also performed on a theoretical member section to further identify the variables which may affect the structural behavior. Parametric study suggests that the section ductility is mainly controlled by the reinforcing index. The influences of the effective prestress and concrete strength on ductility is found to be insignificant. Fiber optic Bragg-grating sensor technology was developed and used to internally and externally measure the deformations and cracking in the specimens.

DOI:

10.14359/1446


Document: 

SP161-11

Date: 

April 1, 1996

Author(s):

R. Ganeswaran and B. V. Rangan

Publication:

Symposium Papers

Volume:

161

Abstract:

Presents the results of a study on long-term deformations of high-strength concrete. Shrinkage and creep deformations of high-strength concretes, as well as deflections of beams and one-way slabs made of high- strength concrete are reported. The measured deformations are compared with the values predicted by the ACI method, the CEB-FIP Model Code, and the Australian Practice. The comparison shows several discrepancies between measured and predicted values.

DOI:

10.14359/1505


Document: 

SP161-10

Date: 

April 1, 1996

Author(s):

P. R. Chakrabarti

Publication:

Symposium Papers

Volume:

161

Abstract:

In this project, an attempt is made to study the instantaneous load- deflection behavior of partially prestressed beams with unbonded post- tensioning tendons. Thirty-three beams with the following variables were tested: different mixes of reinforcing and prestressing steel, T-beams and rectangular beams, normal and high-strength concrete, low and high ratios of span/depth, and different effective stresses in tendons. Cracking was observed and deflections measured at precracking and postcracking stages. A suitable method for deflection calculation at precracking and postcracking stages is proposed. The proposed deflections and the deflections obtained by current ACI 318-89/92 code equations are compared with the measured deflections.

DOI:

10.14359/1503


Document: 

SP161-01

Date: 

April 1, 1996

Author(s):

Russel S. Fling

Publication:

Symposium Papers

Volume:

161

Abstract:

An 8000 sq ft (740 sq m) portion of an industrial building was load tested and vertical movements measured to an accuracy of 0.0043 in. (0.11 mm). Measured deflections were compared to those estimated before testing and to revised estimates after testing. Using simplified procedures and judicious estimates of design parameters, computed deflection normally should be within 40 percent of actual average deflection; the coefficient of variation should be less than 50 percent. With a complete and accurate selection of design parameters, the accuracy and statistical variability can be improved to 15 and 40 percent, respectively.

DOI:

10.14359/1436


123

Results Per Page