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Revista IBRACON de Estruturas e Materiais

On-line version ISSN 1983-4195

Rev. IBRACON Estrut. Mater. vol.2 no.1 São Paulo Mar. 2009

http://dx.doi.org/10.1590/S1983-41952009000100005 

Strength and deformability of hollow concrete blocks: correlation of block and cylindrical sample test results

 

Resistência e deformabilidade de blocos vazados de concreto: correlação entre os resultados experimentais de blocos e corpos-de-prova cilíndricos

 

 

C. S. BarbosaI; J.b. HanaiII

IPh.D. Student, School of Engineering at Sao Carlos, Department of Structural Engineering, University of Sao Paulo, claudiusbarbosa@yahoo.com.br . Av. do Trabalhador Sao Carlense, 400, 13566-590 Sao Carlos, Brazil
IIProfessor, School of Engineering at Sao Carlos, Department of Structural Engineering, University of Sao Paulo, jbhanai@sc.usp.br . Av. do Trabalhador Sao Carlense, 400, 13566-590 Sao Carlos, Brazil

 

 


ABSTRACT

This paper deals with correlations among mechanical properties of hollow blocks and those of concrete used to make them. Concrete hollow blocks and test samples were moulded with plastic consistency concrete, to assure the same material in all cases, in three diferente levels of strength (nominally 10 N/mm², 20 N/mm² and 30 N/mm²). The mechanical properties and structural behaviour in axial compression and tension tests were determined by standard tests in blocks and cylinders. Stress and strain analyses were made based on concrete’s modulus of elasticity obtained in the sample tests as well as on measured strain in the blocks’ face-shells and webs. A peculiar stress-strain analysis, based on the superposition of effects, provided an estimation of the block load capacity based on its deformations. In addition, a tentative method to preview the block deformability from the concrete mechanical properties is described and tested. This analysis is a part of a broader research that aims to support a detailed structural analysis of blocks, prisms and masonry constructions.

Keywords: structural masonry, concrete block, mechanical properties, strength, deformability.


RESUMO

Este trabalho trata das correlações entre as propriedades mecânicas de blocos vazados e do concreto que o constitui. Foram moldados blocos vazados e corpos-de-prova com concreto de consistência plástica para que fosse garantido o mesmo material em todos os casos, para três diferentes níveis de resistência (10 N/mm², 20 N/mm² e 30 N/mm²). As propriedades mecânicas e o comportamento estrutural sob compressão axial e tração foram obtidos por meio de ensaios padronizados com blocos e corpos-de-prova. Uma análise de tensões e deformações foi realizada com base no módulo de elasticidade do concreto obtido no ensaio com corpo-de-prova e também por meio da medição da deformação nas paredes longitudinais e septos transversais dos blocos. Uma análise peculiar sobre a relação tensão-deformação, baseada na superposição dos efeitos, permitiu a previsão da capacidade de carga do bloco a partir dos valores de suas deformações. Além disso, um método de previsão da deformabilidade do bloco a partir das propriedades mecânicas do concreto e descrito e avaliado. Este estudo é parte de uma pesquisa mais ampla que objetiva estudar detalhadamente do comportamento estrutural de blocos, prismas e paredes.

Palavras-chave: alvenaria estrutural, bloco de concreto, propriedades mechanicas, resistência, deformabilidade.


 

 

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Full text avaliable only in PDF.

 

 

REFERENCES

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[11] GANZERLI, S. et al. Compression strength testing for nonstandard concrete masonry units. In: NORTH AMERICAN MASONRY CONFERENCE, 9., 2003, Clemson, South Carolina. Proceedings. p.60-71, 2003.         [ Links ]

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[13] BARBOSA, C.S. Strength and deformability of concrete hollow blocks and their correlation to mechanical properties of the constituent material. 153p. M.Sc. Thesis - School of Engineering of Sao Carlos, University of Sao Paulo, Sao Carlos, 2004. (in Portuguese).         [ Links ]

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[15] BRAZILIAN ASSOCIATION OF TECHNICAL CODES. NBR 7184: Hollow concrete blocks for masonry - Evaluation of compressive strength. Rio de Janeiro, 1982.         [ Links ]

 

 

Received 06/06/2007
Accepted 16/01/2009
Available Online 03/04/2009

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