The approach to cultural heritage

reconstruction of the Posočje region

after earthquakes

Samo Gostič, Blaž Dolinšek, Igor Janežič

Building and Civil Engineering Institute ZRMK, Ljubljana

Earthquakes in Posočje region (river Soča)

Furlanija, 1976, 2x

M 6.5, 6.1, EMS IX-X

(in Slovenia: VIII 12.000 build., 4.200)

1998, 12.4.

M 5.6, EMS VII-VIII 4.055, 500

2004, 12.7.

M 4.9, EMS VII 1.764, 20

prehistoric and historic evidences of strong earthquakes in the area

(b.c. 13000, a.d. 1348, a.d. 1511)

Building stock

• 75% buildings older than 1976

• stone masonry, wooden floors or reinforced concrete

• built during shortage

of materials (after WW)

• new buildings with

brick masonry (after

1976 as confined m.)

• a few RC buildings,

prefabricated wooden

houses (preformed well)

Damage

• 1976: 12.000 buildings, 4.200 beyond repair

• 1998: 4.055 damaged, 500 unsafe, 1.829 reconstructed with governmental aid fund, 82 cult. monuments, 169 secular CH

• 2004: 1.764 damaged, 20 unsafe, 685 buildings in the programme, 286 finished reconstructions, 58 cult. monuments of them 45 finished

The goals of renewal programme

• strengthen the constructions to earthquake safe level – residential buildings have priority

– best practice reconstruction techniques info

• preserving cultural heritage and landscape – repair has priority over replacement (after

1998, less importance after 2004)

– financial support to cover such preserving works

• revitalization of region for faster development – renewal of infrastructure

– reconstruction of cultural monuments/heritage

Difficulties

• earthquake non-resistant building stock

– stone masonry

• underdeveloped area

– low funds of owners

– complicated ownership of buildings

• sudden amount of work

– lack of skilled designers and workers

– lack of equipment (special equipment needed)

– possible increase of prices

• changes of legislation

– higher demands if reconstructing

– different grant schemes, protocols

Tasks of new State Technical Office for the renewal of Posočje

• administration and design – assessment of damage

– provisional proposals of reconstruction

– advising owners about funding arrangement

– support for getting building approvals

– design of less demanding reconstruction

– supervise design done by external companies

– informing public, training designers, workers

• monitor works and funds spending – supervision and

– accountancy of reconstruction works

– reporting to government

up to 100 engineers after 1998

Legal arrangements

• government 12.06.1998 declared the Post-earthquake Reconstruction of Structures and Development Promotion in Posočje Act - ZPOOSRP

• modified to Removal of Consequences of Natural Disasters Act - ZOPNN (2005)

• type of buildings in aid programme – residential buildings (40% .. 80% grant)

– office buildings (up to 40% grant)

– buildings of local community (schools, fire stations, cultural centres…up to 60%)

– cultural heritage: sacral buildings (churches, chapels) and restoration works on them (up to 100%)

– secular cultural monuments and facades of protected town centres (up to 100% of costs for façade)

Pre

serv

ing

the

cu

ltu

ral l

and

scap

e

• connect load bearing elements

– steel ties

– anchoring RC slabs, roofing

– exchange/stiffen wooden floors with RC

• strengthen load bearing structure

– cement grout injections of stone masonry

– refill of cracks or rebuilding in brick masonry

– RC coating of brick masonry walls

• remove or anchor ‘loose’ elements (ornaments, chimneys)

• strengthen foundations

Strengthening methods for masonry buildings

Connecting load-bearing walls with steel ties

double steel ties

f 20..24mm

anchorage plates

Strengthening stone masonry walls with grout injections

typical stone masonry

grout injections

Special considerations for churches

• similar methods as for ordinary but due to earthquake resistance

problematic geometry and limitations of measures invasiveness and appearance more complicated and expensive

• connect load bearing elements

– steel ties or perfo ties (inside wall)

– anchoring RC slabs, roofing

– exchange/stiffen wooden floors with RC/planking

• strengthen load bearing structure

– cement grout injections of stone masonry

– refill of cracks or rebuilding in brick masonry

– RC coating of brick masonry walls

• remove or anchor ‘loose’ elements (ornaments, chimneys)

• restoration works (frescos, altars, stone ornaments…)

• strengthen foundations

Changes in legislation

• governmental programme & grant scheme

– 1976: quickly replace demolished villages with prefabricated houses, grants to owners

– 1998: reconstruct residential buildings with care for architecture landscape and cultural heritage, partial grants to owners with spending control (Post-earthquake

Reconstruction of Structures and Development of Posočje Act)

– 2004: reconstruct or replace (considering economic, functional and appearance aspects), partial or full grants to owners (Elimination of Consequences of Natural Disasters Act)

• building permit

– 1998: common methods can be applied on the basis of notification of works, ‘expert reports’ by STO (80%)

– 2004: regular procedure (with support from STO)

• design codes

– 1976: by the seismic regulations issued in 1964

– 1998: by the upgraded regulations from 1981

– 2004: reconstruct to the demand of Eurocode 8 (demand by STO)

– 2008: Eurocode 8 is obligatory in Slovenia

Financial aspects

• 1998: % of S-design (limited to load bearing structure)

– 81,3 mio € of governmental grant

• 2004: % of all reconstruction costs

– 62,1 mio € planned

Conclusions

• earthquakes will happen

• setting up a managing State Technical Office was necessary for achieving goals of Posočje renewal:

– building stock was updated to safer construction practice and proper residential premises for earthquake victims

– revitalized area for tourist use with the local infrastructure repaired for faster economic development of the region

– special care for preservation of cultural heritage monuments and preservation of typical cultural landscape.

• buildings by modern codes withstand earthquake very well

• presented technical solutions for reconstruction proved adequate if the execution was consisted

• delicate balance needed between choice for reconstruction/replacement considering:

– costs, public interest (ie. heritage value, land planning), functionality for residents, sustainability