1. Nonlinear response- history analysis in design practice RUTHERFORD & CHEKENE November 2007 Joe Maffei

2. RUTHERFORD & CHEKENE

4. Why do NLRH? The code makes us. (Base isolation or supplemental damping) Substantiation of non-prescriptive (“alternative”) designs. We want to know what happens. What is the value of NLRH?

5. Outline Example projects Unique value of NLRH Findings from NLRH of tall buildings Dispersion of NLRH results Ground motion input Conclusions [Modeling uncertainty]

6. Example projects that used NLRH

7. RUTHERFORD & CHEKENE

9. Education Tower

10. RUTHERFORD & CHEKENE

11. Buildings with supplemental damping RUTHERFORD & CHEKENE

12. Waterfront pier structures

13. RUTHERFORD & CHEKENE Exploratorium – Piers 15 and 17

14. Non-prescriptive seismic design

15. BASE 13th ROOF

16. What is the unique value of NLRH? …

17. To determine what happens, not how much. Desired mechanism RUTHERFORD & CHEKENE Undesirable mechanism

18. Findings from NLRH analyses of high-rise buildings

19. Runs scaled from 0.1x MCE to 4x MCE

21. Core wall moment versus shear amplification

22. Moment to shear ratio 110’ at 0.6x MCE 90’ at MCE 57’ at 2x MCE 230’ 175’

23. Use NLRH to determine what happens, more than how much. RUTHERFORD & CHEKENE

24. Coupled wall Plastic hinge locations RUTHERFORD & CHEKENE

27. Dispersion of results among 7 or 14 ground motion records

28. 14 NLRH RUNS BASE 13th ROOF Roof Displ. Ft. Wall Shear at Base Kips Wall Moment at 13 th 1000xK- ft. Min Max Mean m+  c.o.v. 2.1’ 6.7’ 4.2’ 5.4’ 0.29 7600 29700 15500 22200 0.43 513 1080 900 1090 0.21 Pushover 5500760

29. Coupling beam rotation

30. Considering dispersion “Demands for ductile actions shall be taken not less than the mean value obtained from the NLRH. Demands for low-ductility actions (e.g., axial and shear response of columns and shear response of walls) shall consider the dispersion of the values obtained from the NLRH.”

31. NLRH ground motion input

32. NLRH INPUT 7 horizontal ground motion pairs 14 response-history runs GRN 270 GRN 180 GRN 270 GRN 180 RUTHERFORD & CHEKENE

33. NLRH analysis at MCE “When the ground motion components [statistically] represent site-specific fault-normal ground motions and fault-parallel ground motions, the components shall be applied to the three-dimensional mathematical analysis model according to the orientation of the fault with respect to the building. When the ground motion components represent random orientations, the components shall be applied to the model at orientation angles that are selected randomly; individual ground motion pairs need not be applied in multiple orientations..”

34. NLRH analysis at MCE “Where applicable, an appropriate number of the ground motion time series shall include near fault and directivity effects such as velocity pulses producing relatively large spectral ordinates at relatively long periods.”

35. Conclusions

36. The most important value of NLRH is that it tells you what the nonlinear mechanism is, and what the overstrength forces are on elements that you want to remain elastic. RUTHERFORD & CHEKENE

38. Modeling uncertainty

40. Olivian

41. Comparison of SAP model by KPFF vs Perform model by R&C

42. EQ4: Test EQ4 PGA = 0.93g

43. EQ4:

44. Experimental results EQ4: Non-linear EQ3: Essentially linear

45. Measured

46. 111 Almaden Ave San Jose

47. Beam connection behavior

48. Beam fiber model

49. Analysis model versus test results

51. Test Specimen RAM Perform finite element model RUTHERFORD & CHEKENE

52. Cyclic pushover results RUTHERFORD & CHEKENE