1. Structural Dynamics Laboratory Department of Engineering Science, University of Oxford First European Conference on Earthquake Engineering and Seismology, Geneva, 3-8 September 2006 Real Time Hybrid Earthquake Simulation of a Steel Column in a 20-Storey Building Paul Bonnet, Martin S Williams, Anthony Blakeborough & Mobin Ojaghi Department of Engineering Science University of Oxford

2. Structural Dynamics Laboratory Department of Engineering Science, University of Oxford First European Conference on Earthquake Engineering and Seismology, Geneva, 3-8 September 2006 Structure of talk Structural Dynamics Laboratory at Oxford Real time substructuring –concept, technical issues 20-storey building –prototype, natural frequencies, physical/numerical substructuring Implementation Results

3. Structural Dynamics Laboratory Department of Engineering Science, University of Oxford First European Conference on Earthquake Engineering and Seismology, Geneva, 3-8 September 2006 Scale-model tests Offshore wind turbine Guyed mast Structural Dynamics Laboratory Jenkin Building Real-time hybrid tests mass/spring systems dissipative devices 2-storey column

4. Structural Dynamics Laboratory Department of Engineering Science, University of Oxford First European Conference on Earthquake Engineering and Seismology, Geneva, 3-8 September 2006 Hydraulic Installation

5. Structural Dynamics Laboratory Department of Engineering Science, University of Oxford First European Conference on Earthquake Engineering and Seismology, Geneva, 3-8 September 2006 Structural Dynamics Lab

6. Structural Dynamics Laboratory Department of Engineering Science, University of Oxford First European Conference on Earthquake Engineering and Seismology, Geneva, 3-8 September 2006 Control Installation

7. Structural Dynamics Laboratory Department of Engineering Science, University of Oxford First European Conference on Earthquake Engineering and Seismology, Geneva, 3-8 September 2006 Substructure testing Split the structure under test into two or more components –Full (or nearly full) scale physical model for difficult bits –Computational model of remainder

8. Structural Dynamics Laboratory Department of Engineering Science, University of Oxford First European Conference on Earthquake Engineering and Seismology, Geneva, 3-8 September 2006 Displacement Control Loop Delay/lag in displacement response Calculation delay Problems

9. Structural Dynamics Laboratory Department of Engineering Science, University of Oxford First European Conference on Earthquake Engineering and Seismology, Geneva, 3-8 September 2006 Delay error

10. Structural Dynamics Laboratory Department of Engineering Science, University of Oxford First European Conference on Earthquake Engineering and Seismology, Geneva, 3-8 September 2006 Chang explicit integration

11. Structural Dynamics Laboratory Department of Engineering Science, University of Oxford First European Conference on Earthquake Engineering and Seismology, Geneva, 3-8 September 2006 Delay compensation

12. Structural Dynamics Laboratory Department of Engineering Science, University of Oxford First European Conference on Earthquake Engineering and Seismology, Geneva, 3-8 September 2006 Prototype structure Single braced bay 20 stories - 3m per storey 230 Mg/floor Chevron braces (only tension brace active) f 1 =0.46 Hz, f 2 =1.42 Hz, f 20 =12.4 Hz

13. Structural Dynamics Laboratory Department of Engineering Science, University of Oxford First European Conference on Earthquake Engineering and Seismology, Geneva, 3-8 September 2006 Physical Scaling Full scale is too large to fit into laboratory Scale to 40% on column height Adjust properties to keep natural frequencies the same

14. Structural Dynamics Laboratory Department of Engineering Science, University of Oxford First European Conference on Earthquake Engineering and Seismology, Geneva, 3-8 September 2006 Physical / Numerical Partitioning

15. Structural Dynamics Laboratory Department of Engineering Science, University of Oxford First European Conference on Earthquake Engineering and Seismology, Geneva, 3-8 September 2006 Physical Substructure

16. Structural Dynamics Laboratory Department of Engineering Science, University of Oxford First European Conference on Earthquake Engineering and Seismology, Geneva, 3-8 September 2006 Actuator coupling

17. Structural Dynamics Laboratory Department of Engineering Science, University of Oxford First European Conference on Earthquake Engineering and Seismology, Geneva, 3-8 September 2006 Numerical substructure Chang integrator Stiffness proportional damping –2% for 1 st mode Integrator time steps –10ms, 20ms & 30ms Measured actuator time delay Horiuchi or Laguerre extrapolator

18. Structural Dynamics Laboratory Department of Engineering Science, University of Oxford First European Conference on Earthquake Engineering and Seismology, Geneva, 3-8 September 2006 El Centro NS component

19. Structural Dynamics Laboratory Department of Engineering Science, University of Oxford First European Conference on Earthquake Engineering and Seismology, Geneva, 3-8 September 2006 Displacement @ level 2 (upper actuator) 40% El Centro

20. Structural Dynamics Laboratory Department of Engineering Science, University of Oxford First European Conference on Earthquake Engineering and Seismology, Geneva, 3-8 September 2006 Numerical – physical displacement comparison Upper actuator Max error: 0.46%

21. Structural Dynamics Laboratory Department of Engineering Science, University of Oxford First European Conference on Earthquake Engineering and Seismology, Geneva, 3-8 September 2006 Floor displacements @40%

22. Structural Dynamics Laboratory Department of Engineering Science, University of Oxford First European Conference on Earthquake Engineering and Seismology, Geneva, 3-8 September 2006 Lower storey shear hysteresis

23. Structural Dynamics Laboratory Department of Engineering Science, University of Oxford First European Conference on Earthquake Engineering and Seismology, Geneva, 3-8 September 2006

24. Structural Dynamics Laboratory Department of Engineering Science, University of Oxford First European Conference on Earthquake Engineering and Seismology, Geneva, 3-8 September 2006 Comparison with Emulation and Test Upper actuator Max error: 1%

25. Structural Dynamics Laboratory Department of Engineering Science, University of Oxford First European Conference on Earthquake Engineering and Seismology, Geneva, 3-8 September 2006 Main findings Small local processor perfectly adequate to perform simple numerical simulation and control of 20 dof model Errors increased with length of computational time step Changs algorithm was best in terms of accuracy and speed of execution At larger time steps Horiuchi extrapolation was less good the Laguerre method

26. Structural Dynamics Laboratory Department of Engineering Science, University of Oxford First European Conference on Earthquake Engineering and Seismology, Geneva, 3-8 September 2006 Further work Extend tests to higher frequencies More plasticity in the physical specimen Non-linear numerical model