Inter-regional dialog between history and contemporary houses -Resource and Disaster-

1. Inter-regional dialog between history and contemporary houses-Resource and Disaster- Hideyuki KOBAYASHI, DR.Eng. Research coordinator for housing information system, Resarch center for advanced information technology Ministry of land and infrastructure management

2. Material flow and stock of sustaining human settlements CO2 CO2 forestry disaster construction rehabilitation mountain Human settlements stock of trees stock of timbers

3. Material flow and stock of sustaining human settlements- example in Nihonmatsu city(1991) – CO2 CO2 forestry disaster demolition 1,660m3 / year construction Rehabilitation 1,183m3 / year 6,000ha forest 1,000,000m3 of timbe Human settlements 280,000m3 of timber stock of trees stock of timbers: 11,295 buildings (1993), housing 30,000 population

4. History of disasters : Nihonmatsu-Japan • Until 1918 : frequently burned by big fire (interval : 20 years in average) • After 1918 : modernized fire services and instroduction of fire resistant material (clay wall, and rooftile) preventedn the wide spread of fire.

5. History of disasters : Japan general • In most cities in Japan, big fire stopped. However, the quite diverse in times: • Earlist cases : several historical cities, like Nara, Imai (early 17th century) • Latest cases : some cities are famous of urban big fire in modern times : Hakodate (1909), Iida(1947), Tottori(1952), Sakata(1976), etc. • Less frequent earthquakes were usually followed by big fires, causing large number of victims.

6. Approaches for disaster prevention • Fire proof houses (clay wall, rooftile) • Water channel and fire services (located at the center of streets, until mobil traffic required to cover them) • Spatial arrangement (width of streets, arrangement of greenery)

7. Modernization • Timber brace, metal joint • From strengthening to pure truss structure • Hiding structural members behind walls • Prefabrication, and industrialization • Increase of man-poser cost, relatively decreasing material cost => change of low cost solution

8. Shaking sensed by houses • Distribution of strength of houses Distribution % of Damaged house Level of shaking=> • Rate of damaged houses

9. Shaking sensed by houses • Co-relation of areal damage rate (timber – steel), Kobe ‘95 % of Damaged timber houses % of Damaged steel houses Level of shaking=> Source: interim report by BRI, 1995.8

10. Shaking sensed by houses • Co-relation of areal damage rate (steel – RC), Kobe ‘95 % of Damaged steel houses % of Damaged RC houses Level of shaking=> Source: interim report by BRI, 1995.8

11. Shaking sensed by houses • Threshold of defferent structures (Kobe ’95) % of damaged house Level of shaking=> Level of shaking

12. Engineering approach: • Design, only considering elements which can be calculated (neglecting traditional elements which are difficult to calculate/explain) • Extension of elements which can be calculated, with more advanced computing capacity (evaluating traditional elements as far as possible)

13. Traditional & empirical approach: • Over-adaptation, in re-constrcution after damage (similar to rehabilitation of injured human body) • Wholistic way of thinking • Forgetting past disasters in normal re-construction (if 60 years < interval) • Next disaster will attack after previous one is forgotten

14. Traditional Timber HouseLocality (Liwa/Lampung/Sumatera, 1994) • Column from G to F • Adaptation: Additional support for important room Learned from past quake 60 yrs ago

15. Traditional Timber HouseLocality (Biak/Irian Jaya, 1996, houses survived tsunami) • Column stuck into Gafter shaken, slunt but still standing

16. Aceh Traditional Timber House • Less Damage from Quake/Tsunami • Straight column(250φ), strengthened by thick ‘Lhue’90×300 • Learned from previous quake/tsunami 200 yrs ago. 0.5m moved from original position Museum house

17. Aceh Traditional Timber House

18. Aceh Traditional Timber House • Under re-construction ‘Lhue’

19. Aceh : Colonial Timber Houses • Timber Platform House on Land • Small timber houses derived, using 12×12 column

20. Aceh : Vulnerability of structure • Wall plates are bearing horizontal shaking, without ‘Lhue’ • Column footing on stone does not reach to roof,

21. Aceh : Invisible details • Carpentry works at joints of timber • Invisible honset working will save buildings

22. Vulnerability of structure • Japanese traditional ‘Lhue’, called ‘Nuki’ • Small, but multiple usage, saving material • Specified in latest revision of structural guideline, after Kobe

23. History of quake in Sumatera • Two sources : (1)Plate boundary and (2)Sumatera fault • 1797(8.2), 1822(?), 1833(~9.0),1861(8.5), 1863(?), 1892(7.7), 1893, 1900, 1907(?), 1908, 1909, 1916, 1921(7<), 1926(<7),1933(Liwa), 1935(7.7) • 1936(7.2), 1942(7.3), 1943(7.3), 1952(6.8), 1964(6.5), 1967(6.1), 1979(6.6), 1984(6.4), 1987(6.6), 1990(6.6), 1994(6.9,Liwa), 1995(7.0), 1997(6.5),2000(7.8), 2002(7.4),2004(9.2),2005(8.7) • Source : Hilman Natawidjaja 2002

24. Material flow and stock of sustaining human settlementsFrom timber to brick CO2 CO2 forestry disaster construction rehabilitation mountain Human settlements stock of trees stock of bricks

25. Brick Factories in Aceh Inside Banda Aceh City (damaged by shaking) Eastern Coast (operating)

26. Brick Factories in West Jawa • Buring rice husks

27. Aceh : Brick Houses Brick (RM) houses still standing in tsunami ruin • Larger in scale, for extended family • Good quality of material and carpentry skill • RC column (25cm), anchored to foundation • 3m as basic distance between colums (short)

28. Aceh : Brick House (sample)

29. Brick House in coastal villages, Aceh Tsunami revealed the inside of structure of rural brick houses, imitating outlooking of urban (lack of anchor, poor reinforcement etc.)

30. Strengthening new brick structure • Usage of re-inforced frame, anchored (250 < diameter) • Appropriate % of cement for bonding (1:3) These have been long disseminated, however sttel bar and cement are determinant items for total construction cost and they tend to reduce.

31. Strengthening new brick structure • Mixed Usage of Brick and Timber - popular in Bali island - promoted in Sukabumi - adopted in Aceh people c.f. Japanese castle / modern continuous foundation

32. Strengthening new timber structure • Plywood wall • 21m2 4 unitsc.a. 20 million Rupiah (’96) • Clay wall • 18 m2c.a. 1 million Rupiah(’95) • Still standing in good • Condition(’05)

33. Strengthening old timber structure • Additional members to regist against horizontal force [Photo : strengthening damaged timber school in Irian Jaya]

34. Conclusion • Disaster-resistant buildings are needed not only for human safety, but also for global warming issues • Engineering approach (evaluation) to traditional solutions will be worth • Not only contemporary techniques, but also traditional techniques in developed countries are worth to try.

35. Proposal • Strengthening newly constructed brick/timber houses will be feasible • Strengthening existing timber houses will be feasible • Economical aspect (cost-benefit) of investment for disaster reduction will be studied. - rough estimation for non-engineered house - precise estimation for engineered house, where asset management scheme is applied