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 97 Abstracts search results

Document: 

SP188

Date: 

August 1, 1999

Author(s):

Editors: Charles W. Dolan, Sami H. Rizkalla, and Antonio Nanni

Publication:

Symposium Papers

Volume:

188

Abstract:

SP-188 This volume presents 24 papers from the Fourth International Symposium and represents a significant expansion in the state of knowledge that has occurred since the First Symposium in 1993.

DOI:

10.14359/14223


Document: 

SP188-96

Date: 

August 1, 1999

Author(s):

V. M. Karbhari, F. Seible, W. Seim, and A. Vasquez

Publication:

Symposium Papers

Volume:

188

Abstract:

Upgrading often becomes a necessity due to changes in usage of buildings due to factors such as deterioration and aging, change in occupancy, or the need for installation of facilities such as air-conditioning, heating, escalators, elevators, additional skylights, or new façade structures. In a number of cases upgrading is related to changes which affect the load bearing components of the structure. Fiber reinforced polymer matrix composites provide an efficient means of both strengthening slabs for enhanced load carrying capacity and for strengthening slabs after installation of cut-outs. This paper reports on a series of tests conducted to assess the comparative efficiencies of a commercially available strip form and a fabric form of material vis-à-vis strengthening ability and ductility. It is shown that material tailoring can result in significant changes in efficiencies. The extension of this to the rehabilitation of cut-outs is also detailed and aspects of an on-going full-scale test program in that area are elucidated.

DOI:

10.14359/5703


Document: 

SP188-88

Date: 

August 1, 1999

Author(s):

F. S. Rostasy and M. Scheibe

Publication:

Symposium Papers

Volume:

188

Abstract:

AFRP tensile elements (bars, strands etc.) can be successfully applied for the pre-tensioning of precast concrete members, for post-tensioning tendons, ground anchors etc. In such applications, the AFRP may come into permanent contact with the alkaline pore solution of concrete or cementitious grout. Many tests prove that such aggressive environment may seriously damage the stressed AFRP and significantly abbreviate its lifetime due to premature stress rupture. The stress rupture strength of FRP is the relevant durability property to ensure the serviceability and safety of a structural concrete member during its service life. The stress rupture behaviour is usually studied on stressed AFRP bars placed in aggressive solutions etc.. It is though evident that such severe environment does not realistically reflect the true environment of AFRP in dense concrete and grout. It is was therefore the aim of the authors to develop - on basis of experiments in several stages and by theoretical studies - an engineering model for the prediction of the stress rupture strength of stressed AFRP in concrete or grout. This model was verified by tests. Provided the stress rupture strength of AFRP in dry air or in alkaline solution etc. was experimentally established afore-hand, the parameters of the mean stress rupture relationship can be sharpened. Additional deliberations are however necessary to transfer the model into the real environment of concrete or grout around the FRP element. Suitable procedures are presented.

DOI:

10.14359/5694


Document: 

SP188-76

Date: 

August 1, 1999

Author(s):

S. Fujii, Y. Matsuzaki, K. Nakano, and H. Fukuyama

Publication:

Symposium Papers

Volume:

188

Abstract:

Using the database consisting of 236 R/C column specimens conducted in Japan, the characteristic behaviors of strengthening by fiber wrapping were analyzed. The following findings were obtained: (1) The amount of shear reinforcement, the span to depth ratio, the axial compressive stress level influence on the strength and deformation capacities of retrofitted columns by fiber sheet wrapping (2) Shear strength of retrofitted columns can be predicted by previous design equations based on the strut and tie models as same as for usual R/C columns, in which the effective fiber strains of about 1% is appropriate. (3) There are few test data about the confining effect of fiber sheet wrapping on bond resistance of longitudinal bars. Further research effort is required to evaluate the shear strength of columns governed by the splitting of cover concrete along longitudinal bars. (4) The ductility ratio can be roughly estimated as a function of the shear to flexural strength ratio. (5) For the specimens with plain round longitudinal bars, the previous equations based on the strut and tie model cannot be applied because of the poor bond capacity.

DOI:

10.14359/5695


Document: 

SP188-89

Date: 

August 1, 1999

Author(s):

M. Mettemeyer, P. Serra, M. D. Wuerthele, G. Schuster, and A. Nanni

Publication:

Symposium Papers

Volume:

188

Abstract:

This paper discusses the procedure and results from in-situ load tests performed on strengthened double tee beams in a precast parking garage. The load tests were performed to evaluate and confirm the performance of the double tees after the members had been strengthened in shear. Carbon FRP sheets were used as shear reinforcement at a 0/90° combination on the stem of each double tee. Load tests were performed on twenty double tees at various locations and floor levels of the parking structure. Each complete load test, including assembling and dismantling of the test equipment, was completed in approximately three hours. Results indicate that the shear strengthening systems increased the capacity of the double tee beams to meet the design load requirements.

DOI:

10.14359/5696


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