Presentation on theme: "Inter-regional dialog between history and contemporary houses -Resource and Disaster- Hideyuki KOBAYASHI, DR.Eng. Research coordinator for housing information."— Presentation transcript:
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
Material flow and stock of sustaining human settlements CO 2 Human settlements mountain forestry CO 2 disaster construction rehabilitation stock of treesstock of timbers
Material flow and stock of sustaining human settlements - example in Nihonmatsu city(1991) – CO 2 Human settlements 280,000m3 of timber 6,000ha forest 1,000,000m3 of timbe forestry CO 2 disaster demolition 1,660m3 / year construction Rehabilitation 1,183m3 / year stock of trees stock of timbers: 11,295 buildings (1993), housing 30,000 population
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.
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 17 th 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.
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)
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
Shaking sensed by houses Distribution of strength of houses Rate of damaged houses Level of shaking=> Distribution % of Damagedhouse
Shaking sensed by houses Co-relation of areal damage rate (timber – steel), Kobe ‘ 95 Level of shaking=> % of Damaged steel houses % of Damaged timber houses Source: interim report by BRI, 1995.8
Shaking sensed by houses Co-relation of areal damage rate (steel – RC), Kobe ‘ 95 Level of shaking=> % of Damaged RC houses % of Damaged steel houses Source: interim report by BRI, 1995.8
Shaking sensed by houses Threshold of defferent structures (Kobe ’95) Level of shaking Level of shaking=> % of damaged house
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)
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
Traditional Timber House Locality (Liwa/Lampung/Sumatera, 1994) Column from G to F Adaptation: Additional support for important room Learned from past quake 60 yrs ago
Traditional Timber House Locality (Biak/Irian Jaya, 1996, houses survived tsunami) Column stuck into G after shaken, slunt but still standing
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
Aceh : Brick Houses 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) Brick (RM) houses still standing in tsunami ruin
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.)
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.
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
Strengthening new timber structure Clay wall 18 m2 c.a. 1 million Rupiah(’95) Still standing in good Condition(’05) Plywood wall 21m2 4 units c.a. 20 million Rupiah (’96)
Strengthening old timber structure Additional members to regist against horizontal force [Photo : strengthening damaged timber school in Irian Jaya]
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.
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