1. Slovenian National Building and Civil Engineering Institute
ASSESSMENT OF DAMAGE AND USABILITY OF EARTHQUAKE-DAMAGED BUILDINGS: EXPERIENCE OF SLOVENIA
Miha Tomaževič
Slovenian National Building and Civil Engineering Institute
Milica Slokar
Administration of Civil Protection and Disaster Relief of the Republic of Slovenia

2. Seismic risk in Slovenia
1/3 of the population of Slovenia is concentrated in regions where earthquakes with PGA = 0,2 g and more are expected with return period of 475 years.
In Ljubljana region, the most densely populated area of the country, where the basic functions of the country are concentrated, seismic hazard is even more severe.
Most of the damage and casualties are due to inadequate seismic behaviour of existing buildings. The existing building stock (mainly unreinforced masonry buildings) is estimated to be almost 50% of the total.

4. Typical heritage masonry buildings in Slovenia
Castles
Urban architecture
Rural architecture
Typical heritage masonry buildings in Slovenia

5. Pre-World War II buildings
Pre-1963 unreinforced masonry tower houes
Pre-World War II buildings
Typical pre-seismic codes masonry residential buildings in Ljubljana

6. History of seismic codes
1895: the earthquake of Ljubljana
: the skyscraper of Ljubljana - base isolation
1963: seismic design recommendations
1964: first Yugoslav seismic code
1981: revised Yugoslav seismic code
1995: Eurocode 8, ENV version translated as alternative
2008: Eurocode 8 mandatory
Existing buildings
1978: law on seismological service
1985: Yugoslav code for repair and strengthening of earthquake-damaged buildings
2008: Eurocode 8-3 Assessment and strengthening of buildings mandatory

7. Experience in earthquake-damage assessment
1974: Kozjansko Region Governmental committee for damage evaluation categories of damage
1976: Friuli earthquakes. Posočje Region Governmental committee for damage evaluation categories of damage, 3 categories of usability
1998: Upper Posočje Region ACPDR. 5 categories of damage, 3 categories of usability. Categories of damage compatible with definitions given in EMS scale
2004: Upper Posočje Region

8. Assessment of usability and damage
Rapid evaluation: To assess usability of buildings and provide information regarding the safety of occupancy and assess the number of inhabitants needing temporary shelters
Detailed evaluation: To provide detailed information regarding the damage to buildings, which can be used as a basis for the assessment of damage costs

9. Pages 2 and 3 of questionnaire for usability and damage assessment

10. GIS-UJME Applications Address search, number of inhabitants calculation

11. Classification of damage to masonry buildings as defined by EMS scale
Damage category 1: negligible to slight damage
Damage category 2: moderate damage
Damage category 3: substantial to heavy damage
Damage category 4: very heavy damage
Damage category 5: partial or total collapse
Classification of damage to masonry buildings as defined by EMS scale

12. Classification of usability
Usable buildings
Temporarily not usable buildings
Unusable buildings

13. Classification of usability
Usable buildings marked green
Restriction:
Building occupancy may continue without limitation
Damage category 1 and 2 :
Undamaged buildings
Slight structural damage
Moderate non-structural damage

14. Classification of usability
Temporarily not usable buildings marked yellow
Restriction:
Occupancy may continue if the safety can be ensured by emergency safety measures. In most cases, the occupancy is not possible until the building is completely repaired and strengthened
Damage category 3:
Substantial damage to structural system
Heavy non-structural damage

15. Classification of usability
Unusable buildings marked red
Restriction:
Unusable, unsafe buildings are demolished and the debris removed
Damage category 4 and 5:
Heavy structural damage, very heavy non-structural damage
Total or near total collapse

16. Assessment procedure
Usability Assessment Commission is usually composed of 2 experts and local guide, who assess 20 –30 buildings per day (rapid assessment).
For easier identification of buildings, special municipality maps in seismic-prone areas of Slovenia have been prepared by ACPDR.
Municipalities are divided into several zones, each including approximately 100
buildings. Each zone is limited by natural
or physical objects (streets, rivers, etc.).

19. The case of the earthquake of Bovec of April 12, 1998
Based on the information received from local staff of Civil Defence, ACPDR immediately mobilised 25 professionals, who inspected the damaged buildings and assessed their usability according to the proposed methodology
Only buildings with permanent residents and some cultural monuments have been included in the rapid evaluation of damage and usability. Four days have been needed to complete rapid evaluation. 952 buildings have been inspected.
311 buildings have been found as temporarily not usable Among them, 1/3 have been seriously damaged, in some cases even beyond repair, and 2/3 have suffered repairable damage. More than 710 people have been temporarily moved to mobile homes, located close to their homes.

20. Experience after the earthquake of 1998
Timely and constant training of professionals, who will be mobilised in the case of an earthquake disaster, for both usability assessment and damage evaluation, is needed Otherwise, significant delays in earthquake disaster mitigation activities can be expected
Therefore, within the earthquake preparedness program of Slovenia, prepared by ACPDR, a continuous training of experts, members of committees for the assessment of damage and usability of earthquake damage buildings has been set forth

21. Experience after the earthquake of 1998
First exercise has been organized during a simulation of an earthquake disaster, carried out in Ljubljana in 1999
In 2001, the members of committees for the assessment of damage and usability of earthquake damage buildings have been educated during courses organized in the ACPDR’s the training centre. In the years to follow, the knowledge has been improved by practical exercises on earthquake- damaged buildings on the site
About 200 professionals have been trained so far

22. THANK YOU!