Steel strap confined high strength concrete under uniaxial cyclic compression

This paper discusses an affordable and effective lateral confinement technique to enhance concrete’s compressive strength and ductility – the steel strapping tensioning technique (SSTT). Considerable studies have been done on the characteristics of SSTT-confined concrete under uniaxial monotonic compression loading, but none has addressed its uniaxial cyclic response. In this paper, 21 high-strength concrete specimens having diameter of 150 mm and height of 300 mm had been cast, laterally pre-tensioned with steel straps in different confining ratios, and tested to failure under uniaxial cyclic and monotonic compression loadings. Results indicated that the basic hypothesis of envelope curve is valid for SSTT-confined high-strength concrete specimens for uniaxial monotonic and cyclic loadings. The development of plastic strain is independent of the confining ratio when the envelope unloading strain exceeds 0.0025. Moreover, SSTT-confinement has the lowest plastic strain compared to several related existing plastic strain models. The stress deterioration ratio is independent of confining ratio and loading patterns. Lastly, the concept which neglects the effect of loading history on the permanent axial strain of the unloading and reloading paths of concrete is invalid because repeated unloading/reloading cycles have demonstrated a cumulative effect on the permanent strain and stress deterioration.

[1]  Kypros Pilakoutas,et al.  Behavior and Modeling of Concrete Columns Confined by External Post-tensioned Strips , 2008 .

[2]  J. Teng,et al.  Stress–strain model for FRP-confined concrete under cyclic axial compression , 2009 .

[3]  Ralejs Tepfers,et al.  Experimental investigation of concrete cylinders confined by carbon FRP sheets under monotonic and cyclic axial compressive loads , 2002 .

[4]  Kypros Pilakoutas,et al.  Axial compressive behavior of concrete actively confined by metal strips; part A: experimental study , 2010 .

[5]  T. H. Wee,et al.  Derivation of the complete stress – strain curves for concrete in compression , 1995 .

[6]  B. Sinha,et al.  STRESS - STRAIN RELATIONS FOR CONCRETE UNDER CYCLIC LOADING , 1964 .

[7]  R. Abbasnia,et al.  Effect of corner radius on stress–strain behavior of FRP confined prisms under axial cyclic compression , 2012 .

[8]  Abdullah Zawawi Awang,et al.  Stress-strain behaviour of high-strength concrete with lateral pre-tensioning confinement , 2013 .

[9]  Kypros Pilakoutas,et al.  Compressive behavior of concrete actively confined by metal strips, part B: analysis , 2010 .

[10]  Stephanos E. Dritsos,et al.  STRUCTURAL REPAIR/STRENGTHENING OF RC COLUMNS , 1995 .

[11]  S. H. Perry,et al.  Cyclic loading of laterally confined concrete columns , 1993 .

[12]  Scott T Smith,et al.  Experimental testing and analytical modeling of CFRP-confined large circular RC columns subjected to cyclic axial compression , 2012 .

[13]  Yan Xiao,et al.  FRP-confined concrete under axial cyclic compression , 2006 .

[14]  Alper Ilki,et al.  COMPRESSIVE BEHAVIOUR OF CARBON FIBRE COMPOSITE JACKETED CONCRETE WITH CIRCULAR AND NON-CIRCULAR CROSS-SECTIONS , 2003 .

[15]  H. Lee,et al.  Behaviour of Steel Strapping Tensioning Technique (SSTT) confined high-strength concrete with different lateral pre-tensioning stresses , 2013 .

[16]  Richard Arnold,et al.  Cyclic Loading of Spirally Reinforced Concrete , 1983 .

[17]  Amir Mirmiran,et al.  Cyclic modeling of FRP-confined concrete with improved ductility , 2006 .