1. A. Pinto ELSA, JRC, Ispra (VA), Italy
Vulnerability Assessment of Buildings Contribution from Large-scale Laboratory Tests
A. Pinto
ELSA, JRC, Ispra (VA), Italy

2. Kocaeli (Turkey) Earthquake, August 17, 1999 (A. Elnashai, 1999)

3. Mt. Parnes, Athens (Greece) Earthquake, Spet. 7, 1999 (M. Fardis & N
Mt. Parnes, Athens (Greece) Earthquake, Spet. 7, 1999 (M. Fardis & N. Bousias, 1999)

4. Reinforced Concrete Buildings
Represent the largest part of the European building stock at risk, in earthquake prone urban areas
Many of the important structures [Hospitals, Schools, Emergency management, …] are RC structures
There is a lack of codified guidelines for seismic Assessment and Re-design, in Europe
Design and Re-design may have different performance requirements

5. Seismic Assessment &Retrofit of RC buildings
Why (causes)?
Issues/Difficulties
Economical and political
High costs - compared with seismic resistance in new construction
Low premium market is willing to pay for higher safety
Tendency of politicians to avoid complex and socially sensitive problems
Design for earthquake resistance: No formal Seismic Design provisions- until the ‘50s in US and ‘60s in Europe
Provisions for design and detailing of members and structures: Standards in mid-’70s in US and mid-80s in Europe
Technical
Much easier to design a new ER buildings than to assess and strength an old one
Lack of codified criteria and rules for redesign, which leads to somehow arbitrary interventions … (existing for masonry buildings …)
Lack of control to the design, construction and maintenance processes

6. Assessment --- Retrofitting
Determines the need for seismic retrofit or not
Identifies particular weakness and deficiencies to be corrected
Requires:
Tools to allow rapid screening and empirical evaluation of existing structures
‘Solutions’:
Conventional procedures
Deformation and displacement based evaluation procedures (Performance and model calibration from Lab Tests required)
Retrofitting
To provide improved seismic performance
Requirements:
Technically feasible
acceptable cost-benefit ratios (cost benefit analysis)
Technical solutions
according to the weakness identified in the assessment procedure (local and/or global) and to the protection required:
Stiffness
Strength
Ductility (deformation capacity)
Damping or isolation

7. Retrofitting ‘guidelines’ (General)
Key ideas
Seismic retrofitting combined with architectural remodeling, rehabilitation and/or change in use
Find a feasible and acceptable solution allowing occupancy during the works
Technical Requirements
Any intervention should not prejudice the safety of any part of the building in any aspect
Continuity of the load path(s) between new and existing elements, floors, …
Foundations ?!
Retrofitting solutions
New Shear-walls
Drift control, May solve irregularity problems, Design according to new codes, Foundations?!
Steel Bracing (with/out dissipation devices)
Very effective
Connection between bracing and concrete very peculiar
Jacketing (Steel, RC, FRC)
Element strength and deformation capacity (local)
Joints ?!

8. ICONS - Topic 2 Assessment Strengthening & Repair
ELSA
TMR-Large-scale Facility
European Laboratory for Structural Assessment (ELSA)
EC, Joint Research Centre, ISIS, SSMU, TP480
2120 Ispra (VA), Italy

9. Assessment Strengthening & Repair The research work is part of research programme of the ICONS TMR-Network Project Participants: E.C. Carvalho, E. Coelho, A. Campos-Costa, LNEC, Lisbon (PT) A.S. Elnashai, R. Pinho, Imperial College of London (UK) M.N. Fardis, S.N. Bousias, G. Tsionis, University of Patras (GR) GM. Calvi, A. Pavese, M. Recla, University of Pavia (IT) P.E. Pinto, G. Monti, University of Rome (IT) J. Bouwkamp, S. Gomez, University of Darmstadt (DE) E. Alarcon, R. Perera, H. Lutz, Univ. Politecnica of Madrid (ES) A. Plumier, University of Liege (BE) JM. Reynouard, INSA de Lyon (FR) A.V. Pinto, G. Verzeletti, J. Molina, H. Varum, ELSA, JRC, Ispra (IT) Other Contributions: M. Griffith, University of Adelaide, Australia The tests at the ELSA laboratory were financed under the TMR - Large-scale Facilities programme of the European Commission

10. Tests on 4-storey RC Frames Objectives
Assessment of a typical RC frame representative of existing buildings
Design and Construction practice of 40~50 years ago
Simplified design (8% seismic coefficient), (concrete - C16/20, Steel - Smooth rounded bars), lap-splicing, 90 degrees bent stirrups, no shear reinforcement in joints, Strong beam - Weak column system
Bare frame vs masonry Infilled frame
Assessment of retrofitting schemes and techniques
Selective Retrofitting solutions (balancing Ductility, Strength and Stiffness)
Shotcrete of existing infill masonry walls
K-bracing with shear-link (additional strength and damping)
Other aspects (Plastic-hinge length, Slab participation, Shear and bending deformations of Stocky column, Joints’ behaviour …)

11. Frame lay-out

12. Beam Reinforcement

13. Column Reinforcement

14. The ICONS Frame

15. Transport

16. Specimen A
Specimen B
ICONS Frames

17. Test Program Specimen B Specimen A Bare Frame (BF)
Selective Retrofit (SR)
K-Bracing/Shear-link (KB)
Specimen B
Infilled Frame (IN)
Shotcrete (SC)
Cyclic Test
Specimen A
PSD Tests

18. Bare Frame and Selective Retrofit Frame Tests
Testing Programme
Pseudo-dynamic tests for increasing earthquake intensities (475, 975 and 2000 yrp)
A ‘complete’ measuring system
Global (Storey forces and displacements)
Local refined [rotations, deformations (joint, slab, column, beam)]
Photographic and video documentation
Detailed damage descriptions
Damage categorization, Reparability …
Vulnerability and ultimate capacity
Quantify Improved performance of retrofitted frame

19. Instrumentation (Inclinometers)

20. Instrumentation (Local)

21. Earthquake Test at ELSA

22. BARE FRAME 3rd storey - Shear-Drift diagrams
475 yrp 975 yrp

23. Max. Inter-storey Drift Profiles

24. BARE FRAME 975 yrp test 3rd Storey collapse

25. Selective Retrofitting Schemes
(Elnashai and Pinho, 1999)
Strength-only intervention
Ductility-only intervention

26. Selective Retrofitting Schemes
Strength-only intervention
Ductility and
Strength intervention
Ductility-only intervention

27. Max. Inter-storey Drift Profiles

28. Max. Drift Profiles

29. Global Drift

30. Max. Inter-storey Drift

32. Infilled Frame with openings

33. Infill construction

34. Max. Drift Profiles

35. Shear-Drift (Storey 1) Infilled and Bare Frame

36. Global Drift

37. Max. Inter-storey Drift

38. Shotcrete

39. “Shotcrete”

40. Max. Drift Profiles

41. Shear-Drift (Storey 1) Shotcrete and Infilled Frame

42. Column Shear-out

43. Column Shear-out

44. Max. Inter-storey Drift

45. Response maximum values

46. Concluding Remarks RC frame Assessment
Storey mechanism
~1% drift for DE
Collapse for 1,4xDE (~2.5% drift)
RC frame with infills Assessment
Much Higher resistance
Hiding irregularity
Much Lower deformation demands
Structural integrity for 1.4xDE but heavy damage to infills
Story mechanism markedly prompted after peak resistance (Softening)
Selective Retrofitting
‘Too good to be true’ well known structural characteristics, high costs, no infills
Withstanding 1.8xDE without serious damages and a stable dissipation mechanism (~3%Drift)
Infill Shotcrete
Infill protection
Slight lower softening and higher ductility
Column Shear-off (Shear-out)

47. ONGOING AND FUTURE PROJECTS AT ELSA

48. SPEAR project ( )
Torsionally Unbalanced Structure to be tested at ELSA:
Simplification of an existing Greek 3-storey building
Designed for gravity loads
Designed using the Greek design code applied from 1954 to 1995
Doubly non symmetric plan configuration, regular in elevation
2-bay frames spanning from 3 to 6 m (10m x 10m)
3-DOF PsD Test
Partners:
JRC (P. Negro), U.Patras (M. Fardis), U.Pavia, U.Rome, IC-London, EQE-London, U.Ljubljana, U.Cyprus, LNEC-Lisbon, Other: ECOLEADER

49. RC Flat-slab Structure (2002-3)
Shear-punching (detailing for seismic)
Essentially non-dissipative (?)
Significantly more flexible than traditional frame/wall or frame structures  Second order, P-d, effects
Additional measures for guiding conception and design

50. JRC-ELSA Institutional Programme (2003-6)
Creation of a Virtual Laboratory:
- To link structural engineering research sites across Europe,
- Provide data storage facilities and repositories,
- Offer remote access to the latest research tools, and
- Enhance experimental techniques and procedures by full exploitation of the electronic communication facilities (enlarged participation in testing preparation, conduction, analysis, distributed testing).
To explore the possibility of developing a common advanced platform for analytical/computational development and simulation