1. Davide Forcellini, Univ. of San Marino Prof. Ahmed Elgamal, Dr. Jinchi Lu, UC San Diego Prof. Kevin Mackie, Univ. of Central Florida SEISMIC ASSESSMENT OF ISOLATED BRIDGE CONFIGURATIONS ADOPTING A PBEE METHODOLOGY

2. BRIDGE PBEE Dr. Jinchi Lu, Prof. Kevin R. Mackie, Prof. Ahmed Elgamal http://peer.berkeley.edu/bridgepbee/

3. CASE STUDY

4. 2 HPs: 1. ELASTIC SPRING ELEMENTS; 2. LONGITUDINAL BEHAVIOUR ONLY CONFIGURATIONS Assumptions: 1. Isolators represented by ELASTIC SPRING ELEMENTS 2. FULL 3D MODEL WITH LONGITUDINAL SHAKING ONLY

5. 2 HPs: 1. ELASTIC SPRING ELEMENTS; 2. LONGITUDINAL BEHAVIOUR ONLY SOIL DEFORMABILITY

6. METHODOLOGY 1.Specification of Ground Motion Input; 2.Bridge-Ground Finite Element Model; 3.Performance-Based Earthquake Engineering Quantities

7. STEP 1: INPUT GROUND MOTION PEER NGA database http://peer.berkeley.edu/nga/ 5 bins of 20 motions: Mw= 6.5-7.2; R = 15-30 km Mw= 6.5-7.2; R = 30-60 km Mw= 5.8-6.5; R = 15-30 km Mw= 5.8-6.5; R = 30-60 km Mw= 5.8-7.2; R = 0-15 km

8. STEP 2: F.E. MODEL FIBER SECTIONS ABUTMENT: ELASTIC ELEMENTS DECK: FORCE- BASED ELEMENTS SOIL: 9-NODE BRICK ELEMENTS

9. STEP 3: PERFORMANCE GROUPS (PGs) TOTAL REPAIR COST RATIO (%) TOTAL REPAIR TIME (CWD)

10. PILOT INVESTIGATION - BASE ISOLATION TECHNIQUE ASSESSMENT - SOIL DEFORMABILITY RESPONSE

11. 2 HPs: 1. ELASTIC SPRING ELEMENTS; 2. LONGITUDINAL BEHAVIOUR ONLY PBEE RESULTS (MODEL COMPARISON)

12. MODEL 1 – SIMPLE ROLLER ISOLATOR Max Long. Drift Ratio (Column) - PG1 Max Long. Relative Deck End Abutment Displacement – PG3

13. influence of SOIL STRENGHT (JEN MOTION)

14. SOFT SOIL STIFF SOIL Deformation for JEN motion at t=10.15 sec SCALE 200 MODEL 1 – influence of SOIL STRENGHT

15. Total Repair Time (Crew Working Days, CWD) Total Repair Cost Ratio (%) MODEL 1 – SIMPLE ROLLER ISOLATOR

16. Max Long. Drift Ratio (Column) - PG1 Max Long. Relative Deck End Abutment Displacement – PG3 MODEL 2 – ABUTMENT ISOLATION

17. Total Repair Time (Crew Working Days, CWD) Total Repair Cost Ratio (%) MODEL 2 – ABUTMENT ISOLATION

18. Max Long. Drift Ratio (Column) - PG1 Max Long. Relative Deck End Abutment Displacement – PG3 MODEL 3 – COLUMN ISOLATION

19. Total Repair Time (Crew Working Days, CWD) Total Repair Cost Ratio (%) MODEL 3 – COLUMN ISOLATION

20. Max Long. Drift Ratio (Column) - PG1 Max Long. Relative Deck End Abutment Displacement – PG3 MODEL 4 – FULL ISOLATION

21. Total Repair Time (Crew Working Days, CWD) Total Repair Cost Ratio (%) MODEL 4 – FULL ISOLATION

22. 2 HPs: 1. ELASTIC SPRING ELEMENTS; 2. LONGITUDINAL BEHAVIOUR ONLY PBEE RESULTS (SOIL COMPARISON)

23. Max Long. Drift Ratio (Column) - PG1 Max Long. Relative Deck End Abutment Displacement – PG3 STIFF CLAY

24. Total Repair Time (Crew Working Days, CWD) Total Repair Cost Ratio (%) STIFF CLAY

25. MODEL 4 – Full isolation MODEL 2 – Abutment isolation Deformation for JEN motion at t=10.15 sec SCALE 200 STIFF CLAY

26. Max Long. Drift Ratio (Column) - PG1 Max Long. Relative Deck End Abutment Displacement – PG3 MEDIUM CLAY

27. Total Repair Time (Crew Working Days, CWD) Total Repair Cost Ratio (%) MEDIUM CLAY

28. Max Long. Drift Ratio (Column) - PG1 Max Long. Relative Deck End Abutment Displacement – PG3 SOFT CLAY

29. Total Repair Time (Crew Working Days, CWD) Total Repair Cost Ratio (%) SOFT CLAY

30. CONCLUSIONS - GROUND ISOLATION IS A KEY PARAMETER THAT MAY SIGNIFICANTLY AFFECT SSI RESPONSE - BENEFIT OF THE ISOLATION TECHNIQUE: SAVE THE COLUMN, POSSIBLY AT THE ABUTMENT’S EXPENSE - ROLE OF DEEP FOUNDATIONS UNDER THE ABUTMENT PREVENTING SETTLEMENTS (REDUCING REPAIR COSTS) - TRANSVERSAL EFFECTS

31. FURTHER APPLICATIONS - TRANSVERSAL EFFECTS ASSESSMENT - IMPLEMENTATION OF NON LINEAR MODELS FOR ISOLATORS

32. THANK YOU FOR YOUR ATTENTION!