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The Torsional and Shear Behavior of Steel Fiber Reinforced RC Members

Abdulkadir Cüneyt AYDIN
Abdulkadir Cüneyt AYDIN
, 
Mahmut KILIÇ
Mahmut KILIÇ
, 
Mahyar MAALI
Mahyar MAALI
, 
Barış BAYRAK
Barış BAYRAK
 and 
Erkan TUNÇ
Erkan TUNÇ
   | Jul 05, 2021
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Article Category: research-article
Published Online: Jul 05, 2021
Page range: 47 - 65
Received: Sep 29, 2020
Accepted: May 01, 2021
DOI: https://doi.org/10.21307/acee-2021-015
© 2019 Abdulkadir Cüneyt Aydin et al., published by Sciendo
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Figure 1.

The geometry and reinforcement details a) tested beams b) tested column specimens (all units are in mm)
The geometry and reinforcement details a) tested beams b) tested column specimens (all units are in mm)

Figure 2.

The stress-strain curves of the reinforcements
The stress-strain curves of the reinforcements

Figure 3.

Test setup a) torsion b) four-point bending c) three-point bending d) overhanging
Test setup a) torsion b) four-point bending c) three-point bending d) overhanging

Figure 4.

The test set-up of axial loading (all units are in mm)
The test set-up of axial loading (all units are in mm)

Figure 5.

Grading curve
Grading curve

Figure 6.

Torsional moment-twist angle relationship
Torsional moment-twist angle relationship

Figure 7.

Cracking pattern at failure a) T-Reference b) T60SF c) T30SF beams
Cracking pattern at failure a) T-Reference b) T60SF c) T30SF beams

Figure 8.

Influence of shear index on the shear capacity of beams by different codes
Influence of shear index on the shear capacity of beams by different codes

Figure 9.

Energy dissipation capacity of tested beams
Energy dissipation capacity of tested beams

Figure 10.

Load displacement relationship a) three-point and b) four-point bending c) overhanging beam
Load displacement relationship a) three-point and b) four-point bending c) overhanging beam

Figure 11.

Crack pattern at failure a) FC-Reference b) FC-30SF c) FC60SF d) F3-30SF e) F3-60SF f) F4-30SF g) F4-60SF
Crack pattern at failure a) FC-Reference b) FC-30SF c) FC60SF d) F3-30SF e) F3-60SF f) F4-30SF g) F4-60SF

Figure 12.

The interaction curves of tested column Bending moment-axial load curves of column
The interaction curves of tested column Bending moment-axial load curves of column

Figure 13.

The columns after tests
The columns after tests

The values defined by standards and experimental results

Specimen Yield force (kN) Yield deflection (mm) Peak force (kN) Peak deflection (mm)
FC-Reference 170.02 3.31 267.95 37.58
FC-30SF 114.18 5.31 257.47 26.79
FC-60SF 132.31 5.51 218.24 12.52
F3-30SF 60.11 2.22 104.36 9.66
F3-60SF 73.51 1.74 113.10 12.80
F4-30SF 122.12 3.27 196.23 12.89
F4-60SF 128.13 4.53 204.37 20.11

Physical properties of steel fiber

Length (mm) 30 Tensile strength (MPa) 1100
Diameter (mm) 0.75 Aspect ratio 0.40

Ultimate load and moment values of tested columns

Group Specimen Ultimate Load (kN) Ultimate Moment (kNm)
Concentric AL-Reference-0 122.6 0
AL-Reference-10 99.6 0.99
AL-Reference-20 95.7 1.91
AL-Reference-30 92.8 2.77
Theoretical Result 0 2.78
Eccentric AL-30SF-0 217.9 0
AL-30SF-10 140.5 1.41
AL-30SF-20 105.9 2.12
AL-30SF-30 99.7 2.99
Theoretical Result 0 2.78
Eccentric AL-60SF-0 142.9 0
AL-60SF-10 99.2 0.99
AL-60SF-20 97.1 1.94
AL-60SF-30 93.8 2.81
Theoretical Result 0 2.79

Concrete mixture

kg/m3 First Group Second Group Third Group
Fine aggregate (0-12mm) 1420 1420 1420
Coarse aggregate (12-28 mm) 510 510 510
Cement 320 320 320
Admixture 6.4 6.4 6.4
Steel fibers — 30 60
Water/Cement ratio 0.31 0.31 0.31
Compressive strength (MPa) 34 32.6 34.4
Flexural strength (MPa) 59.0 58.3 58.6
Splitting tensile strength (MPa) 32.1 33.2 42.4

The comparison of experimental and numerical results

Specimens TU-Exp Tu-mode II/Tu-exp TTS-2018/TU-Exp TAC318-14/TU-Exp TEurocode-2/TU-Exp TAS3600/TU-Exp TBS8110/TU-Exp THsu/TU-Exp TRauch/TU-Exp
T-Reference 5.37 - 0.67 0.67 0.70 0.86 0.47 1.12 1.24
T30SF 7.50 0.58 0.48 0.48 0.50 0.62 0.34 0.79 0.89
T60SF 11.06 0.40 0.33 0.32 0.34 0.42 0.23 0.55 0.60

The experimental results

Specimens Vu-Exp (kN) Vn-ACI (kN) V ( n − A C I ) / V ( u − E x p ) V n − E U 2 ( k N ) V ( n − E U 2 ) / V ( u − E x p ) Energy Dissipation Capacity (kNmm)
FC-Reference 267.95 64.89 0.24 72.84 0.27 1302.7
FC-30SF 257.47 64.19 0.25 72.84 0.28 5726.1
FC-60SF 218.24 65.09 0.30 72.84 0.33 1122.3
F3-30SF 104.36 64.19 0.62 72.84 0.70 266.3
F3-60SF 113.10 65.09 0.58 72.84 0.64 226.4
F4-30SF 196.23 64.19 0.33 72.84 0.37 887.6
F4-60SF 204.37 65.09 0.32 72.84 0.36 1313.8

Summary of tested specimens

Specimens Steel Fibers (kg/m3) Loading Type
T-Reference — Torsion
T30SF 30 Torsion
T60SF 60 Torsion
FC-Reference — Overhanging
FC-30SF 30 Overhanging
FC-60SF 60 Overhanging
F3-30SF 30 Three-point bending
F3-60SF 60 Three-point bending
F4-30SF 30 Four-point bending
F4-60SF 60 Four-point bending
AL-Reference-0 — Axial load without eccentricity
AL-Reference-10 — Axial load with 10 mm eccentricity
AL-Reference-20 — Axial load with 20 mm eccentricity
AL-Reference-30 — Axial load with 30 mm eccentricity
AL-30SF-0 30 Axial load without eccentricity
AL-30SF-10 30 Axial load with 10 mm eccentricity
AL-30SF-20 30 Axial load with 20 mm eccentricity
AL-30SF-30 30 Axial load with 30 mm eccentricity
AL-60SF-0 60 Axial load without eccentricity
AL-60SF-10 60 Axial load with 10 mm eccentricity
AL-60SF-20 60 Axial load with 20 mm eccentricity
AL-60SF-30 60 Axial load with 30 mm eccentricity

Chemical, physical and mechanical properties of the cement

Chemical properties (%) Physical and mechanical properties
SO3 2.84 2 days Compressive strength (MPa) 27.90
MgO 2.58 28 days Compressive strength (MPa) 58.00
CaO 63.65 Initial setting time (min) 151
Al2O3 4.48 Final setting time (min) 191
K2O 0.62 Specific gravity (g/cm3) 3.12
SiO2 18.10 Specific surface (cm2/g) 3690
Na2O 0.21 Total volume exp. (mm) 1.0
Fe2O3 3.09 Water requirement of cement (%) 29.5
CI- 0.015 Fineness (%) 7.15

The Experimental results of torsional tests

Specimens Tu (kNm) θu (deg/m) Tcr (kNm) θcr (deg/m) θyeld (deg/m) μθ Energy Dissipation Capacity (kN.deg)
T-Reference 5.37 2.55 0.29 1.60 2.14 1.19 12.02
T30SF 7.50 3.06 0.50 1.62 2.46 1.24 20.17
T60SF 11.06 5.58 0.60 1.31 4.30 1.30 54.72
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