1. Tests of High-Performance Fiber- Reinforced Concrete Coupling Beams James K. Wight F.E. Richart, Jr. Collegiate Professor Dept. of Civil and Env. Eng. University of Michigan Co-Researchers: Gustavo Parra-Montesinos and Remy Lequesne, Afsin Canbolat and Monthian Setkit

2. Key Thought Change from better rebar details to enhanced material properties

3. Mt. McKinley Bldg., Anchorage, Alaska - 1964

4. Diagonal Reinforcement, L/d ≈ 1 100% of flexural and shear strength

5. Construction Issues, L/d ≈ 2 Low angle and reinforcement congestion

6. Research Objectives Use HPFRC to reduce transverse and diagonal reinforcement requirements in coupling beams Develop information on shear strength and damage tolerance of HPFRC members subjected to large displacement reversals Investigate the use of precast HPFRC coupling beams in earthquake-resistant coupled wall systems

7. Test Specimens 4 D13 SP-1SP-2 3 D16

8. Test Setup Actuator Precast Coupling Beam “Rigid” Links Wall Block

9. Test Specimens 4 D13 SP-1SP-2 3 D16

10. Test Specimens 2 D16 SP-3SP-4 2 D16

11. Construction issues: Beam embedment

12. CB-2 design (L/d = 1.75)

13. Precast Coupling Beam Extra mid-depth reinforcement used to move flexural hinging away from cold joint

14. CB-2 behavior

15. CB-2 During Testing 3% Drift 5.5% Drift

16. Four story coupled-wall specimen 25% scale axial load in lower stories slabs for load transfer at 2 nd and 4 th levels

17. Reinforcement Detail, RC Wall Confinement spacing: Design wall concrete shear stress

18. Reinforcement details, RC Wall

19. RC Wall Behavior; ~ 42% coupling ratio

20. Reinforcement Detail, FRC Wall Confinement spacing: Design wall concrete shear stress

21. Comparison of Wall Behavior

22. R/C HPFRC At system drift of 1.5%: o HPFRC: 1 mm cracks o RC: Spalling of cover to expose many stirrups Damage Tolerance HPFRC coupling beams are significantly more damage tolerant than reinforced concrete beams HPFRC R/C

23. HPFRC Wall Damage

24. Conclusions – stout coupling beams Adequate confinement of diagonal reinforcement is achieved by HPFRC without the need for bar-type confinement reinforcement Contribution of HPFRC to shear capacity of coupling beams is significant and must be considered in design Precast coupling beam placement proved to be simple and is believed to be a viable alternative method for assembling a coupled-wall system

25. http://nees.org/warehouse/project/47 Innovative Applications of Damage Tolerant Fiber-Reinforced Cementitious Materials for New Earthquake-Resistant Structural Systems and Retrofit of Existing Structures