A research experiment has been conducted on the structural performance of repaired minor damaged reinforced concrete beam and column Joints using composite known as CFRP (Carbon Fiber Reinforced Polymer) under simulated cyclic 2D loadings to find the practical lamination repair scheme for flexural strengthening, shear strengthening, and joint strengthening.

1. Repair and Retrofit Systems for Reinforced Concrete Beam-Column Joints using Carbon Fiber Reinforced Polymer (CFRP) subjected to cyclic/seismic loadings – Research in progress

2. Student Researchers: AmeraldSimanungkalit (Presenter) Brendon Baich Tuan Quoc Le Faculty Advisors: Dr. Uksun Kim Dr. PinakiChakrabarti Dr. David Naish Lab Technicians: Leroy Sanchez (Civil Engineering Dept.) John (Mechanical Engineering Dept.)

3. Acknowledgements(Funding)

4. Two recent enormous California earthquakes : Loma Prieta (1989) and Northridge (1994)

5. Loma Prieta earthquake October 17, 1989 a magnitude earthquake measured 6.9 that caused 63 deaths, injured 3,757 people a 8,000 to 12,000 people homeless. The aftermath of the earthquake totaled approximately 6 to 13 billion dollars in damages.

6. Loma Prieta Earthquake RESIDENTIALS FREEWAYS BRIDGES PARKING STRUCTURE

7. Northridge earthquake January 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.

8. Northridge Earthquake PARKING STRUCTURE BRIDGES HOSPITALS APARTMENTS

9. 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)

10. Civil Engineers Duty Provide Solutions : 1. Safety 2. Practical 3. Cost Efficient 4. List goes on….

11. Structural Element: Joint Failures Focal point of research since 1994 Northridge EQ in structural engineering community

12. Vcol C2 = Ts2 Vb2 Vb1 C1 = Ts2 Vcol (b) internal stress resultants acting on joint Joint Mechanism (a) moments, shears, axial loads acting on joint

13. Repair and Retrofit Solutions Bonded steel plates Steel or concrete jackets External post-tensioning to the structural elements AFTER BEFORE

15. Required Chemicals (epoxy, resin, etc) the cost of the material is balanced by much lower installation costs.

16. CFRP (Carbon Fiber Reinforced Polymer)

17. CFRP Property& Manufacture

18. Previous research done at CSUF 1998 Dr. Chakrabarti 2009 “Study of Concrete Beam Column Joint Repair with Carbon Fiber Reinforced Polymer” (2009) By Delgado, H, and Lam, C.

19. Improvement from previous Fully externally wrap CFRP (not practical) Excess materials or layers of lamination (not economical)

20. Improvement from previous Precise Data (Test set-up improvement) Shifting (Moving) Additional prestressing wires on beams (Specimen 3&4)

21. Construction of Specimens – Rebar and Formworks STEEL CAGES FORMWORKS GRINDING REBARS FOR STRAIN GAGES INSPECTIONS

22. Construction of Specimens – Concrete Pouring SLUMP TEST FORMWORKS LAYOUT CYLINDER AND BEAM TESTS 28 DAYS – CONCRETE CURING

23. Material Testing PRESTRESSING WIRES HYDRAULIC JACKS LOAD TEST COMPRESSION TEST UNIVERSAL TESTING MACHINE (UTM) ACI 318-08 ACI 440.2R-08 FLEXURE TEST

24. Typical Specimen Details STRAIN GAGES

25. Typical Specimen Section Details 4

26. Experiment Test Set-up

27. Test on Specimen#1 (RCBC-1)

28. Cracking Behavior SHEAR CRACKS

29. Result Data Load vs Deflection - No Shifting Not symmetrical

30. CFRP Proposal Scheme

31. 3D Rendering

32. Apply CFRP Increased Load

33. Research Expectations After comparing the controlled and repair specimens: Accurate result data Better performance (higher Loadings) Practical CFRP repair scheme Providing less layers CFRP and resin materials Providing new standard set-up for the next research (post tension beam)

34. Thank You Amerald Simanungkalit, EIT, S.M. ASCE. Amerald24@CSU.Fullerton.edu Questions? BEAM TO COLUMN JOINTS