The approach to cultural heritage reconstruction of the Posočje region after earthquakes

Transcription

1 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

2 Earthquakes in Posočje region (river Soča) Furlanija, 1976, 2x M 6.5, 6.1, EMS IX-X (in Slovenia: VIII build., 4.200) 1998, M 5.6, EMS VII-VIII 4.055, 500 prehistoric and historic evidences of strong earthquakes in the area (b.c , a.d. 1348, a.d. 1511) 2004, M 4.9, EMS VII 1.764, 20

3 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)

4 Damage 1976: buildings, beyond repair 1998: damaged, 500 unsafe, reconstructed with governmental aid fund, 82 cult. monuments, 169 secular CH 2004: damaged, 20 unsafe, 685 buildings in the programme, 286 finished reconstructions, 58 cult. monuments of them 45 finished

5 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

6 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

7 Tasks of new State Technical Office for the renewal of Posočje up to 100 engineers administration and design after 1998 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

8 Legal arrangements government 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)

9 Preserving the cultural landscape

10 Strengthening methods for connect load bearing elements steel ties masonry buildings 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

11 Connecting load-bearing walls with steel ties double steel ties f mm anchorage plates

12 Strengthening stone masonry walls with grout injections typical stone masonry grout injections

13 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

14 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 : by the upgraded regulations from : reconstruct to the demand of Eurocode 8 (demand by STO) 2008: Eurocode 8 is obligatory in Slovenia

15 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

16 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