Potential of High Performance Fiber Reinforced Concrete for Damage Mitigation and Reinforcement Detailing Simplification

Chung-Chan Hung

Professor of Civil EngineeringNational Cheng Kung University

C.-C. HungDept of Civil Engineering, NCKU

High Performance Fiber Reinforced Concrete(HPFRC)

Engineered Cementitious Composites(ECC)

Tensile Strain

Tensile Stress

Regular Concrete

Ultra High Performance Fiber Reinforced Concrete

(UHPFRC)

High Performance Fiber Reinforced Concrete (HPFRC)

C.-C. HungDept of Civil Engineering, NCKU

materials optimization

HPFRC ferrocement

tension stiffening

self-healing performance

high-rise structural walls

columns coupling beamsshear wallsstrengthening

ductility

Multi-Scale Research on HPFRC at NCKU

C.-C. HungDept of Civil Engineering, NCKU

111µm

Self-healing Performance of HPFRC

------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- C.-C. Hung, Y.-F. Su. Mechanical properties and self-healing evaluation of strain-hardening cementitious composites with high volumes of hybrid pozzolan materials.

Energy dispersive x-ray (EDX) analyses

SEM image

C.-C. HungDept of Civil Engineering, NCKU

0

50

100

150

200

250

300

350

0 0.001 0.002 0.003

Loa

d (

kN)

Strain

S7-F0S7-F2Bare #7 Steel Bar

050100150200250300350400450

0 0.001 0.002 0.003

Loa

d (

kN)

Strain

S7-F2S7-F2-CBare #7 Steel Bar

Tension Stiffening Performance of UHPFRCmonotonic behavior cyclic behavior

Bare #7 steel barUHPFRCHSC

UHPFRC - monotonic loadingUHPFRC - reversed loadingBare #7 steel bar

UHPFRC

#7 steel bar

C.-C. HungDept of Civil Engineering, NCKU

600

1000

1000 250

350

4-#8

#3@300

#3@30025 150 #3@75

200A

A' Section AA'

39cm

33cm

4cm

4cm

cement

40

40

390

330

U-shape jacket

(+)positive loading direction

1000mm2200

mm

Load Cell

Actuator

Strong floor

LVDT

RC foundation

Loading frame

Rotation gaugeSteel plate

Wire gauge

Prestressed steel rods(+)positive loading direction

-200-150-100-50

050

100150200

-9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9Fo

rce

(KN

)Drift (%)

(1.7,130)

(-1.0,-104)(-1.9,-131)

(1.1,106)

-200-150-100-50

050

100150200

-9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9

Forc

e (K

N)

Drift (%)

(2.0,144)

(-1.1,-130)(-2.0,-143)

(1.2,137)

HPFRC Jacketing for Structural Retrofitting Jacketing without steel reinforcement

-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------C.-C. Hung, Y.-S. Chen. Innovative ECC Jacketing for Retrofitting Shear-Deficient RC Members. Construction & Building Materials. 111, pp. 408-418, 2016.

unit:mm

C.-C. HungDept of Civil Engineering, NCKU

-3000-2400-1800-1200

-6000

6001200180024003000

-5 -4 -3 -2 -1 0 1 2 3 4 5

Forc

e (kN

)

Drift (%)

ACI-14-18.10

ACI-14-18.10

x yielding of boundary element steelO yielding of web vertical steel• yielding of web horizontal steel Mn/hw

Mn/hw

-3000-2400-1800-1200

-6000

6001200180024003000

-5 -4 -3 -2 -1 0 1 2 3 4 5

Forc

e (kN

)

Drift (%)

ACI-14-18.10

ACI-14-18.10x yielding of boundary element stee• yielding of web horizontal steel

Mn/hw

Mn/hw

High Strength Steel Reinforced Squat UHPFRC Shear Walls

Wall design shear = 5Vc

-----------------------------------------------------------------------------------------------------------------------------------------------------------C.-C. Hung, H. Li, H.-C. Chen. High-strength Steel Reinforced Squat UHPFRC Shear Walls: Cyclic Behavior and Design Implications. Engineering Structures. 141, pp.59-74, 2017.

High strength concrete UHPFRC

C.-C. HungDept of Civil Engineering, NCKU

High Strength Steel Reinforced FRC Coupling Beams

-2000

-1500

-1000

-500

0

500

1000

1500

2000

-8 -6 -4 -2 0 2 4 6 8Sh

earf

orce

(kN

)Drift ratio(%)

CB80B

CB80FB

Add 1.5% Fiber

• without fibers • with 1.5% fibers

Beam shear demand = 8Vc

HSC

HSC+ 1.5% fibers

C.-C. HungDept of Civil Engineering, NCKU

UHPFRC columnHigh strength concrete column

Slender UHPFRC Columns under Concentric Loads

C.-C. HungDept of Civil Engineering, NCKU

UHPFRC columnHigh strength concrete column

Slender UHPFRC Columns under Eccentric Loads

C.-C. HungDept of Civil Engineering, NCKU

RC systemHPFRC system

-0.025 -0.02 -0.015 -0.01 -0.005 01

2

3

4

5

6

Wall Rotation (rad)

Floo

r

1% drift

2.5% drift3.3% drift

-0.025 -0.02 -0.015 -0.01 -0.005 01

2

3

4

5

6

Wall Rotation (rad)

Floo

r

1% drift

2.5% drift

3.3% drift

HPFRC Coupled Structural Walls

(i) -0.03 beam rotation

(ii) 0.012 beam rotation

(iii) -0.013 beam rotation

(iv) residual cracks

Crack patterns in coupling beams

RC coupling beamsHPFRC coupling beams

C.-C. HungDept of Civil Engineering, NCKU

Potential future research directions for HPFRC

Quantifying the benefits of fibers for

enhancing structural performance

simplifying reinforcement detailing

680 mm