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SlabSys-HFRC – Flat slabs for multi-storey buildings using hybrid reinforced self-compacting concrete: an innovative structural system

2015-09-30

This project aims to contribute for the development of a new generation of flat slabs, for multi-storey buildings, made of hybrid fibre reinforced concrete, by substituting most of the conventional reinforcement of the slab with hybrid discrete fibres, and by using concrete mixes with self-compacting ability. When compared to conventionally reinforced concrete (RC) flat slabs, the proposed structural system should have an enhanced cracking behaviour and flexural stiffness for serviceability limit states, while maintaining a flexural ductile failure mode for ultimate limit states. Also, several benefits are harvested regarding construction times and quality, labour costs, sustainability during construction, cracking behaviour, as well as increased durability.

In traditional techniques for executing RC flat slabs, placement of reinforcement is one of the most time consuming tasks, which involves a lot of workforce (with frequent occurrence of injuries) and equipment. The replacement of conventional rebar by discrete fibres, with significant benefits in regard to time of construction (and with a competitive price), has been made in many applications of slabs on grade with a quite good performance. Nevertheless, conventional fibre reinforced concrete, FRC, is seen suspiciously by the construction professionals. For this, much contributes the high coefficients of variation, CoV, of the material’s mechanical strengths. The appearance and dissemination of new advanced cement matrices with self-compacting capability contributed to an increase of the confidence level on these FRC. This confidence step-up, mainly due to lower CoV pushed forward the utilization of self-compacting FRC for slabs suspended on piles (with considerable reduction of rebar). Moreover, the outcome of FRC with enhanced mechanical strengths has been pushing the span limits upwards. Recent pilot experiences show the feasibility of building elevated FRC slabs with 5-8m spans (using high percentages of fibres). The results obtained so far in these pilot experiences appear promising, but they fail to address important issues such as: actual service life behaviour; they study ultimate limit states mostly by using yield line methods, but advanced modelling techniques for interpretation are not used; they also lack to provide user friendly guidelines with detailed background information for designers and contractors. Thus, the main purpose of this research proposal is to develop a high performance reinforcing system that can be a competitive alternative to conventional RC slabs of multi-storey buildings.

Project ID: PTDC/ECM/120394/2010

Coordinator: Vítor Manuel Couto Fernandes Cunha

Promoting Institution: University of Minho

Financing Institution: Fundação para a Ciência e a Tecnologia

Budget: €148.095,00

Start date: 01-04-2012

End date: 30-09-2015

Companies/Institution that collaborated in this project:
- Casais S.A. (www.casais.pt)
- CiviTest Lda. (www.civitest.pt)
- Tecnipor - Gomes & Taveira Lda. (www.tecnipor.com.pt)
- Sika Portugal - Produtos Construção e Indústria, S.A. (www.sika.pt)
- SAR - Soluções de Automação e Robótica (www.sarobotica.pt)

The main objectives of the present project were:

1 - Development of the HFRSCC;

2 - Material characterization of HFRSCC;

3 - Assessment of the structural performance of HFRSCC;

4 - Quality control and establishment of parameter estimation methodology for design purposes;

5 - Punching shear behaviour (experimental and numerical research);

6 - Construction of a full scale prototype;

7 - Guide for construction and design of HFRSCC slabs.

A1 - Project's management

A2 - Development of the hybrid fibre reinforced concrete

A3 - Material characterization of HFRSCC

A4 - Assessment of the structural performance of HFRSCC

A5 - Quality control and establishment of parameter estimation methodology for design purposes

A6 - Punching shear behaviour of HFRSCC (experimental and numerical research)

A7 - Construction of a full scale prototype

A8 - Guide for construction and design of HFRSCC slabs

BEFIB2012 – 8th RILEM International Symposium on Fibre Reinforced Concrete: challenges and opportunities, September 2012

BE2012 – Encontro Nacional Betão Estrutural, BE2012, Outubro 2012.

IBRACON2012 – 54º Congresso Brasileiro do Concreto (IBRACON 2012), Outubro 2012

FC2013 – 7th International Conference on Fibre Concrete, 12 a 13 setembro, Praga, República Checa

PCF2014 – XIV Portuguese Conference on Fracture, 6 a 7 de fevereiro, Peso da Régua (2014)

BAC2015 – IV Congresso Ibero-americano sobre Betão Auto-compactável – BAC2015, FEUP, 6-7 de julho de 2015

PhD theses

1.Moraes Neto, B. N., "Comportamento à Punção de Lajes Lisas em Concreto Reforçado com Fibras de Aço Sob Carregamento Simétrico", Tese de doutoramento, Universidade de Brasília e Universidade do Minho, 2013.

2.Amin Abrimshabaf, “Creep Behaviour of Cracked Steel Fibre Reinforced Self – Compacting Concrete Laminar Structures”, PhD Thesis, University of Minho, 2015.


MSc theses

3.Hélder Celso Araújo Eira, “Punçoamento de lajes fungiformes de betão auto-compactável reforçadas com fibras de aço”, MSc Thesis, University of Minho, 2013.


Papers in ISI international journals

4. B.N. Moraes Neto, J.A.O. Barros, G.S.S.A. Melo, "A model for the prediction of the punching resistance of steel fibre reinforced concrete slabs centrically loaded", Construction and Building Materials Journal, Vol. 46, pp. 211–223, 2013.

5. B.N. Moraes Neto, J.A.O. Barros, G.S.S.A. Melo, "A model to simulate the constribution of fibre reinforcement for the punching resistance of RC slabs", Journal of Materials in Civil Engineering, Vol. 26, Nº7 , 2014.

6. Hamidreza Salehian, Joaquim A.O. Barros, Mahsa Taheri, Evaluation of the influence of post-cracking response of steel fibre reinforced concrete (SFRC) on load carrying capacity of SFRC panels, Construction and Building Materials, Volume 73, 30 December 2014, Pages 289-304

7. Abrishambaf A, Barros JAO, Cunha VMCF, Time-dependent flexural behaviour of cracked steel fibre reinforced self-compacting concrete panels, Cement and Concrete Research, Elsevier, 72: 21–36, 2015.

8. Marcos Daniel Esteves Teixeira, Joaquim Barros, Vítor Cunha, Bernardo Moraes-Neto, António Ventura-Gouveia, "Numerical Simulation of the Punching Shear Behaviour of Fibre Reinforced Self-Compacting Concrete Flat Slabs", Construction and Building Materials Journal, 74: 25–36, 2015.

9. Amin Abrishambaf, Vitor Cunha, Joaquim Barros, "On the tensile properties and Fracture behaviour of steel fibre reinforced self-compacting concrete laminar structures", Journal of Fracture and Structural Integrity, 31: 54-66, 2015.

10. Joaquim A.O. Barros, Bernardo N. Moraes Neto, Guilherme S.S.A. Melo, Cristina M.V. Frazão, Assessment of the effectiveness of steel fibre reinforcement for the punching resistance of flat slabs by experimental research and design approach, Composites Part B: Engineering, Volume 78, 1 September 2015, Pages 8-25



Papers in national journals

11. Moraes Neto, B.N.; Barros, J.A.O.; Melo, G.S.S.A., “Simulação do contributo dos mecanismos de reforço de fibras de aço para a resistência ao punçoamento de lajes fungiformes”, Revista Portuguesa de Engenharia de Estruturas, Janeiro 2015, pp. 63-74.


Papers in international conferences

12. Cunha VMCF, Barros JAO, Sena-Cruz JM, Numerical simulation of indirect tensile tests – Two distinct approaches, em: BEFIB2012 – 8th RILEM International Symposium on Fibre Reinforced Concrete: challenges and opportunities, Eds: Joaquim Barros et al., 12pp., September 2012.

13. Moraes-Neto, B.N.; Barros, J.A.O.; Melo, G.S., “The predictive performance of design models for the punching resistance of SFRC slabs in inner column loading conditions”, 8th RILEM International Symposium on Fibre Reinforced Concrete: challenges and opportunities, Eds: Joaquim Barros et al., 12pp., 19-21 September 2012.

14. Barros JAO, Teixeira M, Cunha VMCF, Neto B, Ventura-Gouveia A, Numerical modelling ofthe punching behavior of steel fibre reinforced self-compacting concrete flat slabs, em: FC2013 - 7th International Conference on Fibre Concrete, 12 a 13 setembro, Praga, República Checa (2013).


Papers in national conferences

15. Moraes-Neto, B.N.; Barros, J.A.O.; Melo, S. G.; Eira, H.C.A., “Avaliação do cálculo da resistência ao punçoamento centrado de lajes fungiformes reforçadas com fibras de aço – Modelos teóricos”, Encontro Nacional Betão Estrutural, BE2012, Artigo 019, 10 pp., Outubro 2012.

16. Barros, J.A.O.; Salehian, H.; Pires, M.; Gonçalves, D.M.F., “Edifícios de habitação e comércio em lajes fungiformes de betão auto-compactável reforçado com fibras de aço”, Anais do 54º Congresso Brasileiro do Concreto (IBRACON 2012), CBC2012, 16pp., Outubro 2012

17. Barros, Joaquim A. O.; Salehian, Hamidreza; Pires, Miguel; Gonçalves, Delfina; “Betão auto-compactável reforçado com fibras de aço no desenvolvimento de novos sistemas estruturais”, Livro de Atas do Ciclo de Workshops Fibranamics, 1-27, 2013

18. Abrishambaf A, Cunha VMCF, Barros JAO, Mechanical performance of fibre reinforced concrete: the role of fibre distribution, em: XIV Portuguese Conference on Fracture, 6 a 7 de fevereiro, Peso da Régua (2014).

19. Abrishambaf A, Cunha VMCF, Barros JAO, Mechanical performance of fibre reinforced concrete: the role of fibre distribution, em: XIV Portuguese Conference on Fracture, 6 a 7 de fevereiro, Peso da Régua (2014).

20. Escusa G, Cunha VMCF, Sena-Cruz JM, Nascimento D., Pereira ENB, Influência do efeito de exposições ambientais no comportamento pós-fissurado de um BAC reforçado com fibras de aço, IV Congresso Ibero-americano sobre Betão Auto-compactável – BAC2015, FEUP, 6-7 de julho de 2015.

21.Joaquim Barros, Hamidreza Salehian, Miguel Pires, Delfina Gonçalves, “Ensaio à rotura de protótipo de edifício em lajes de betão autocompactável reforçado com fibras”, IV Congresso Ibero-americano sobre Betão Auto-compactável – BAC2015, FEUP, 6-7 de julho de 2015



Reports

22.Cunha VMCF, Abrishambaf A, Barros JAO, Moraes Neto, B N, Pereira EN, Ventura-Gouveia A, Lourenço L, Flat slabs for multi-storey buildings using hybrid reinforced self-compacting concrete: an innovative structural system, Report 2015-DEC/E43, pp. 114, University of Minho, Guimarães, Portugal (2015).

23. Abrishambaf A, Barros JAO, Cunha VMCF “A two-phase material approach to model steel fibre reinforced self-compacting concrete panels” Report 14-JUL/E-20, University of Minho, Guimarães, Portugal (2014).

24. Abrishambaf A, Barros JAO, Cunha VMCF “Creep performance of the cracked steel fibre reinforced self-compacting concrete elements.” Report 14-JUL/E-19, University of Minho, Guimarães, Portugal (2014).

25. Abrishambaf A, Barros JAO, Cunha VMCF “Determining the time-dependent behaviour of bond by the means of fibre pullout creep test.” Report 14-JUL/E-18, University of Minho, Guimarães, Portugal (2014).

- Seminar

- Publications in International and National Journals

- Publications in International and Nacional Conferences

- Oral presentations on Conferences

- Meeting of Technical Committees

- RepositóriUM

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