EGU Vienna 2007

1. Impact of seismic
retrofit on interwar RC
housing
Maria BOSTENARU
Rui PINHO
ROSE School, Pavia, Italy

2. Overview
 Introduction
 Modelling of interwar housing buildings
 Earthquake behaviour of interwar buildings
 Retrofit, and discussion of the impact of such
measures
 Optimisation of a retrofit measure
 Conclusions

3. Modelling of interwar housing
buildings
 The IVth CIAM in 1933 in Athens and
architectural characteristics of historic RC
housing buildings in earthquake prone parts
of Europe
 Structural characteristics

4. Modern buildings in Greece

5. Bedroom / night zone
Living room, including dinning
Corridors / circulation zone
Bathrooms, toillets
Kitchen
Hall / vertical circulation
Deposit / external circulation
Legend:
Functional scheme in a Greek
apartment building

6. Modern buildings in Romania

7. Functional scheme in a
Romanian apartment building
Bedroom / night zone
Living room, including dinning
Corridors / circulation zone
Bathrooms, toillets
Kitchen
Hall / vertical circulation
Deposit / external circulation
Legend:

8. Architectural typology
Bedroom / night zone
Living room, including dinning
Corridors / circulation zone
Bathrooms, toillets
Kitchen
Hall / vertical circulation
Deposit / external circulation
Legend:
1.
2. 3.

9. Modern buildings in Portugal

10. Earthquake behaviour of
interwar buildings
 Design of a model of an interwar building
 Effects of earthquakes on the structure

11. Model building:
facade and section

12. Model building:
plan of the current floor

13. Model building: plans of GF,
basement and set-back floors

14. Material models for concrete
and steel

15. Slab modeling

16. Section models

17. Finite elements model of the
building

18. Pushover curves
pushover X
0
500
1000
1500
2000
2500
3000
3500
4000
4500
5000
0 50 100 150 200 250 300 350 400
Displacement N6206 (mm)
Baseshear(kN)
Base Shear X
Base Shear X negative
pushover Y
0
500
1000
1500
2000
2500
3000
3500
4000
4500
5000
0 50 100 150 200 250 300 350 400
Displacement N6206 (mm)
Baseshear(kN)
Base Shear Y
Base Shear Y negative

19. Retrofit, and discussion of the
impact of such measures
 Design of the retrofit measure
 Impact of the measure

20. Layout of retrofit elements
1st phase:
soft storey
2nd phase
3rd phase

21. Retrofit options
pushover X
0
500
1000
1500
2000
2500
3000
3500
4000
4500
5000
0 50 100 150 200 250
Displacement N6206 (mm)
Baseshear(kN)
Base Shear X
Base Shear X retrofit2
Base Shear X retrofit 3
pushover Y
0
500
1000
1500
2000
2500
3000
3500
4000
4500
5000
-15 35 85 135 185 235 285 335
Displacement N6206
Baseshear(N)
Base Shear Y
Base Shear Y retrofit2
Base Shear Y retrofit3

22. Deformed shapes

23. Most damaged elements
yield and spall GF
most damaged upper floor columns
Vrancea earthquake 1986
yield 1st floor
yield, spall GF
yield, spall, crush GF
yield GF
most damaged transversal beams
Vrancea earthquake 1986
yield in GF
beams
yield, crush in
GF beams
yield, spall, crush in GF
beams
most damaged longitudinal beams
Vrancea earthquake 1986
crush, spall, yield
GF
spall GF
yield 1st floor
yield GF
spall 1st floor
most damaged upper floor columns
Vrancea earthquake 1977
most damaged GF columns (also break)
Vrancea earthquake 1977
yield in beams
over basement
spall in beams
over basement
yield in beams over
1st and 2nd floor
most damaged longitudinal beams
Vrancea earthquake 1977
.
yield GF
yield, spall GF
most damaged beams
Thessaloniki earthquake 1978
yield GF
yield, spall GF
most damaged longitudinal beams
Vrancea earthquake 1990

24. Optimisation of a retrofit
measure
 Optimisation of impact parameters
 Re-assessment of the impact

25. Pushover curves
X
0
0,05
0,1
0,15
0,2
0,25
0 20 40 60 80 100 120 140 160
displacement (mm)
acceleration(g)
unretrofitted 94 retrofitted negative 0,192
Y
0
0,05
0,1
0,15
0,2
0,25
0 50 100 150 200
displacement (mm)
acceleration(g)
unretrofitted retrofitted 103 negative 0.192

26. Decision
tree
Historical
Building
Element
Material
Vulnerability
Structure
performance
Retrofit
elements
Strategy
Architect Engineer
Inhabitant Investor
Execution
Acceptance
Occupancy
Management
Availability
Indicators
Residential value
Reversibility
Guidelines
Displacement, maximal
Tension
Facade
Interior space
Structure
Demolition
Size change
Looks change
Construction material change
Material
Earthquake
Shape score
Structure score
Forces
Displacement, remaining
Element replacement
New element
Non-structural > structural
System completion
Strengthening/Stiffening
Enhanced ductility
Reduced demand
Duration
Noise
Relocation
Participation
Ownership form
Safety
Own expenses
Other benefits
During measure
After measure
After earthquake
Total costs/New bldg. – 30%
Aggregate
Building site
Phases
Repeatability
Construction material versus
Technology versus
Funds
Relocation space
Reparation/New building
Retrofit/New building
Reparation saving/Retrofit
Compatibility with old
Conservation of old
Maintenance new
Sustainability
Partial demolition

27. Detail of the model building

28. Geo-composite yarn weaving

29. Conclusions

30. Thank you!
Questions?