Repair and Retrofit Systems for Reinforced Concrete Beam-Column Joints using Carbon

Fiber Reinforced Polymer (CFRP) subjected to cyclic/seismic loadings – Research in progress

Student Researchers: Amerald Simanungkalit (Presenter)

Brendon Baich Tuan Quoc Le

Faculty Advisors: Dr. Uksun Kim

Dr. Pinaki ChakrabartiDr. David Naish

Lab Technicians:Leroy Sanchez (Civil Engineering Dept.)

John (Mechanical Engineering Dept.)

Acknowledgements(Funding)

Two recent enormous California earthquakes :

Loma Prieta (1989) and Northridge (1994)

Loma Prieta earthquakeOctober 17, 1989a magnitude earthquake

measured 6.9 that caused 63 deaths,

injured 3,757 people a8,000 to 12,000 people

homeless. The aftermath of the

earthquake totaled approximately 6 to 13 billion dollars in damages.

Loma Prieta Earthquake

FREEWAYS RESIDENTIALS

PARKING STRUCTURE

BRIDGES

Northridge earthquakeJanuary 17, 1994 with a magnitude

earthquake measured 6.9 that caused 72 deaths, over

9,000 injuries The aftermath of the

earthquake totaled approximately $20 billion in damages.

Northridge Earthquake

BRIDGESPARKING STRUCTURE

APARTMENTS HOSPITALS

Unfortunately, “ California has a 99.7%

chance of having a magnitude 6.7 or larger earthquake during the next 30 years. The likelihood of a more powerful quake of magnitude 7.5 or greater in the next 30 years is 46%”

Southern California Earthquake Center (SCEC)

& U.S Geological Survey (USGS)

Civil Engineers Duty

Provide Solutions :

1. Safety2. Practical3. Cost Efficient

4. List goes on….

Structural Element: Joint Failures

Focal point of research since 1994 Northridge EQ in structural engineering community

Joint Mechanism

(a) moments, shears, axial loads acting on joint

(b) internal stress resultants acting on

joint

C2 = Ts2

C1 = Ts2

Vcol

Vcol

Vb1Vb2

Repair and Retrofit SolutionsBonded steel platesSteel or concrete jackets External post-tensioning

to the structural elements

AFTER BEFORE

Repair & Retrofit using CFRPPros

Highest strength, Highest stiffness, Most durable

fibers. Highly resistant

to most environmental conditions.

Low creepHigh fatigue

endurance.

Cons fabricate this

composite material is very expensive compared to traditional concrete and steel materials.

Required Chemicals (epoxy, resin, etc)

the cost of the material is balanced by much lower installation costs.

CFRP (Carbon Fiber Reinforced Polymer)

CFRP Property& Manufacture

Previous research done at CSUF

“Study of Concrete Beam Column Joint Repair with Carbon Fiber Reinforced Polymer” (2009) By Delgado, H, and Lam, C.

1998

2009

Dr. Chakrabarti

Improvement from previous

Fully externally wrap CFRP

(not practical)

Excess materials or layers of lamination

(not economical)

Improvement from previous

Precise Data (Test set-up improvement)

Shifting (Moving)

Additional prestressing wires on beams (Specimen 3&4)

Construction of Specimens – Rebar and Formworks

STEEL CAGES FORMWORKS

GRINDING REBARS FOR STRAIN GAGES INSPECTIONS

Construction of Specimens – Concrete Pouring

CYLINDER AND BEAM TESTS

SLUMP TEST

FORMWORKS LAYOUT

28 DAYS – CONCRETE CURING

Material Testing

UNIVERSALTESTINGMACHINE (UTM)

COMPRESSION TEST

FLEXURE TEST

PRESTRESSING WIRESHYDRAULIC JACKSLOAD TEST

ACI 318-08ACI 440.2R-08

Typical Specimen Details

STRAIN GAGES

Typical Specimen Section Details

4

Experiment Test Set-up

Test on Specimen#1 (RCBC-1)

Cracking Behavior

SHEAR CRACKS

Result Data

Load vs Deflection - No ShiftingNot symmetrical

CFRP Proposal Scheme

3D Rendering

Apply CFRP Increased Load

Research ExpectationsAfter comparing the controlled and repair

specimens:Accurate result dataBetter performance (higher Loadings)Practical CFRP repair schemeProviding less layers CFRP and resin

materialsProviding new standard set-up for the next

research (post tension beam)

Thank YouAmerald Simanungkalit, EIT, S.M. ASCE.

Amerald24@CSU.Fullerton.edu

Questions?BEAM TO COLUMN JOINTS