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Active confinement of weakened concrete columns

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Abstract

This paper investigates the advantages of using of external active confinement to improve the compression load capacity of concrete cylinders using mild steel band clamps. For this, passive and actively pre-stressed steel bands have been attached to concrete cylinders to mimic real structural columns which may otherwise have to be removed and replaced due to poor strength performance. The experimental programme included compression load testing a number of unreinforced concrete cylindrical specimens to establish the effect the confinement had on the compressive load-carrying capacity and the stress–strain behaviour. A number of parameters were investigated in the study including the effect of varying the band spacing, volumetric ratio and passive and active confining forces. It was found that confining the concrete did produce an increase in compressive strength. However, the different levels of pre-stress used had no significant effect on strength but did influence the confined concrete stress–strain behaviour with greater lateral stresses at peak strength observed. Ductility increases were observed for confined specimens and significant axial strains achieved with noticeable peak strength enhancements. However, due to initial misfit between the bands and the concrete in the passive confinement state, confining forces generated only contained the cracked specimens. The actively pre-stressing confinement yielded an increase in load capacity of 53 % as the bands were fully activated.

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Abbreviations

E s :

Modulus of elasticity of transverse reinforcement (MPa)

\(f_{\text{cc}}^{'}\) :

Compression strength of confined concrete (MPa)

\(f_{\text{h}}^{'}\) :

Stress in confinement reinforcement at peak strength (MPa)

f c :

Stress acting on confined concrete (MPa)

f co :

Concrete cylinder compression strength (N/mm2)

f h :

Stress in confinement reinforcement (MPa)

f hy :

Yield strength of transverse reinforcement (MPa)

\(I_{\text{e}}^{'}\) :

Effective confinement index evaluated at peak strength

I e :

Effective confinement index

\(I_{\text{e50}}^{'}\) :

Effective confinement index evaluated at ε cc50

k 1, k 2 :

Parameters controlling shape of post-peak portion of stress–strain curve

s :

Spacing between ties (mm)

δ H :

Gap width (mm)

ε cc :

Axial strain at peak strength of confined concrete

ε c :

Axial strain in confined concrete

ε cc50 :

Post-peak axial strain in confined concrete when capacity drops to 50 % of confined strength

ε co :

Axial strain corresponding to concrete cylinder strength

ε co50 :

Post-peak axial strain in unconfined concrete when capacity drops to 50 % of unconfined strength

κ :

Parameter used to determine if yielding of transverse reinforcement occurs at peak strength of confined concrete

ρ cc :

Ratio of longitudinal–lateral reinforcement

ρ s :

Effective volumetric ratio of transverse reinforcement

ρ sey :

Effective sectional ratio of confinement reinforcement in y direction

A H :

Area of transverse reinforcement within spacing s (mm2)

d s :

Diameter of spiral or hoop between bar centres (mm2)

\(f_{\text{l}}^{'}\) :

Effective confinement stress (MPa)

\(f_{ 1}^{'}\) :

Effective lateral confining pressure (MPa)

References

  1. ASTM C39 (2004) Standard test method for compressive strength of cylindrical concrete specimens

  2. BS EN 12350-2 (2009) Testing fresh concrete. Slump-test

  3. Cusson D, Paultre P (1995) Stress-strain model for confined high-strength concrete. ASCE J Struct Eng 121(3):468–477

  4. De Lorenzis L, Tamužs V, Tepfers R, Valdmanis V, Vilks U (2004) Stability of CFRP-confined columns. In: Innovative materials and technologies for construction and restoration conference, Lecce, pp 327–342

  5. EN 197-1 (2000) Cement: composition, specifications and conformity criteria for common cements. British Standards Institution, London

  6. Fardis MN (2009) Seismic design, assessment and retrofitting of concrete buildings based on EN-Eurocode 8. Springer, Dordrecht

    Book  Google Scholar 

  7. Frangou M, Pilakoutas K, Dritsos S (1995) Structural repair/strengthening of RC columns. Constr Build Mater J 9(5):259–266

    Article  Google Scholar 

  8. Ilki A, Peker O, Karamuk E, Demir C, Kumbasar N (2008) FRP retrofit of low and medium strength circular and rectangular reinforced concrete columns. J Mater Civ Eng 20:169–188

    Article  Google Scholar 

  9. Iyengar KT, Desayi P, Reddy KN (1970) Stress–strain characteristics of concrete confined in steel binders. Mag Concr Res 22(72):173–184

    Article  Google Scholar 

  10. Janke L, Czaderski C, Ruth J, Motavalli M (2009) Experiments on the residual load-bearing capacity of prestressed confined concrete columns. Eng Struct 31(10):2247–2256

    Article  Google Scholar 

  11. Legeron F, Paultre P (2003) Uniaxial confinement model for normal and high strength concrete columns. ASCE J Struct Eng 129:241–252

    Article  Google Scholar 

  12. Mirmiran A, Shahawy M (1997) Dilation characteristics of confined concrete. Mech Cohesive Frict Mater 2:237–249

    Article  Google Scholar 

  13. Moghaddam H, Samadi M, Pilakoutas K, Mohebbi S (2010) Axial compressive behavior of concrete actively confined by metal strips; part A: experimental study. Mater Struct 43:1369–1381

    Article  Google Scholar 

  14. Moghaddam H, Samadi M, Pilakoutas K (2010) Compressive behavior of concrete actively confined by metal strips, part B: analysis. Mater Struct 43:1383–1396

    Article  Google Scholar 

  15. Richart FE, Brandtzaeg A, Brown RL (1929) The failure of plain and spirally reinforced concrete in compression. University of Illinois Engineering Experiment Station, Bulletin No.190, Urbana, IL

  16. Rodriguez M, Park R (1994) Seismic load tests of reinforced concrete columns strengthened by jacketing. Struct J Am Concr Inst 91:150–159

    Google Scholar 

  17. Rousakis T (2013) Hybrid confinement of concrete by FRP sheets and fiber ropes under cyclic axial compressive loading. ASCE J Compos Constr 17(5):732–743

    Article  Google Scholar 

  18. Rousakis T (2014) Elastic fiber ropes of ultrahigh-extension capacity in strengthening of concrete through confinement. ASCE J Mater Civ Eng 26(1):34–44

    Article  Google Scholar 

  19. Rousakis TC, Karabinis AI (2012) Adequately FRP confined reinforced concrete columns under axial compressive monotonic or cyclic loading. RILEM Mater Struct Springer Neth 45(7):957–975

    Article  Google Scholar 

  20. Rousakis TC, Tourtouras IS (2014) RC columns of square section—passive and active confinement with composite ropes. Elsevier J Compos B 58(March):573–581

    Article  Google Scholar 

  21. Saatcioglu M, Razvi SR (1992) Strength and ductility of confined concrete. ASCE J Struct Eng 118(6):1590–1607

    Article  Google Scholar 

  22. Shin M, Andrawes B (2010) Experimental investigation of actively confined concrete using shape memory alloys. Eng Struct 32(3):656–664

    Article  Google Scholar 

  23. Tamuzs V, Tepfers R, You C-S, Rousakis T, Repelis I, Skruls V, Vilks U (2006) Behaviour of concrete cylinders confined by carbon-composite tapes and prestressed yarns 1—experimental data. Mech Compos Mater 42(1):13–32

    Article  Google Scholar 

  24. Tamužs V, Tepfers R, Zīle E, Valdmanis V (2008) Mechanical behaviour of FRP-confined concrete columns under axial compressive loading. In: 5th International engineering and construction conference (IECC’5). American Society of Civil Engineers, International Committee, Los Angeles Section, pp 223–241

  25. Tepfers R (2012) Concerning concrete E-modulus. In: Riga Technical University 53rd international scientific conference dedicated to the 150th anniversary and the 1st congress of world engineers and Riga Polytechnic Institute/RTU Alumni. DIGEST, pp 360–361. ISBN 978-9934-10-360-5

  26. Valdmanis V, De Lorenzis L, Rousakis T, Tepfers R (2007) Behaviour and capacity of CFRP-confined concrete cylinders subjected to monotonic and cyclic axial compressive load. Struct Concr 8(7):187–200

  27. Xiao Y, Wu H (2003) Retrofit of reinforced concrete columns using partially stiffened steel jackets. ASCE J Struct Eng 129(6):725–732

    Article  Google Scholar 

  28. Yan Z, Pantelides CP, Reaveley LD (2007) Posttensioned FRP composite shells for concrete confinement. ASCE J Compos Constr 11(1):81–90

    Article  Google Scholar 

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Authors and Affiliations

  1. School of Civil & Structural Engineering, Dublin Institute of Technology, Bolton Street, Dublin 1, Ireland

    N. Holmes, D. Niall & C. O’Shea

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  1. N. Holmes
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  2. D. Niall
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  3. C. O’Shea
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Correspondence to N. Holmes.

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Holmes, N., Niall, D. & O’Shea, C. Active confinement of weakened concrete columns. Mater Struct 48, 2759–2777 (2015). https://doi.org/10.1617/s11527-014-0352-1

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  • DOI: https://doi.org/10.1617/s11527-014-0352-1

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