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Climate change and Urban Vulnerability in Africa

Climate change and Urban Vulnerability in Africa. Assessing vulnerability of urban systems , population and goods in relation to natural and man-made disasters in Africa. “Training on the job” Course on Hazards, Risk and (Bayesian) multi-risk assessement

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Climate change and Urban Vulnerability in Africa

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  1. Climate change and Urban Vulnerability in Africa Assessingvulnerability of urbansystems, population and goods in relation to natural and man-made disasters in Africa “Training on the job” Course on Hazards, Risk and (Bayesian) multi-risk assessement Napoli, 24.10.2011 – 11.11.2011 24/09/2014 Fatemeh Jalayer, Francesco De Paola, Raffaele De Risi

  2. Case study: from climatic data to flooding risk assessment - Application for Informal settlements in Tanzania. 24/09/2014 Fatemeh Jalayer, Francesco De Paola, Raffaele De Risi 2

  3. Risk assessment: The engineering point of view R = H• V • E R : risk H : hazard V : vulnerability E : exposure Fatemeh Jalayer, Francesco De Paola, Raffaele De Risi

  4. Reliability of informal settlements To evaluate the mean annual rate of exceeding of a given flood height respect to the structural capacity height it’s necessary to calculate the follow integral: Fragility (1 structure; 1 building typology, k building typology) Hazard where: Is the collapse probability for a class of structures, given a specific flood height value; Is the mean annual rate of exceeding given flood height; Fatemeh Jalayer, Francesco De Paola, Raffaele De Risi

  5. Reliability of informal settlements Class of structures BUILDING TYPOLOGY IDENTIFICATION N Buildings Ntype,1 Type,1 - the construction techniques       - the method used for constructing the bricks       - type of the mortar used       - presence or absence of lintel beams       - foundation type and height from the ground       - the existence of drainage system       - the material used for roof beams       - the material used for roof cover       - type and number of openings       - the division of internal spaces       - possible reinforcing used in the wall corners       - the techniques used for anchorage of roof inside the wall       - general geometrical characteristics y Informal settlements Ntype,2 Type,2 … … Ntype,i Type,i … … Ntype,k Type,k x Fatemeh Jalayer, Francesco De Paola, Raffaele De Risi

  6. Reliability of informal settlements Example Fatemeh Jalayer, Francesco De Paola, Raffaele De Risi

  7. Reliability of informal settlements Example • Hinged • Hinged 3 2 1 • Fixed 1 2 3 Fatemeh Jalayer, Francesco De Paola, Raffaele De Risi

  8. Reliability of informal settlements Example 100 % 75 % 50 % 25 % Fatemeh Jalayer, Francesco De Paola, Raffaele De Risi

  9. Reliability of informal settlements Example 100 % 75 % 50 % 25 % Fatemeh Jalayer, Francesco De Paola, Raffaele De Risi

  10. Reliability of informal settlements Example Structural Population Thickness 3 values: 20 cm 30 cm 40 cm Mechanical Material Property: 25% 50% 75% 100% Total: 72 cases 3m 4m 5m Fatemeh Jalayer, Francesco De Paola, Raffaele De Risi

  11. Reliability of informal settlements Example Structural Fragility Fatemeh Jalayer, Francesco De Paola, Raffaele De Risi

  12. Reliability of informal settlements Example Flood hazard TR=10years Fatemeh Jalayer, Francesco De Paola, Raffaele De Risi

  13. Reliability of informal settlements Example Flood hazard TR=30years Fatemeh Jalayer, Francesco De Paola, Raffaele De Risi

  14. Reliability of informal settlements Example Flood hazard TR=50years Fatemeh Jalayer, Francesco De Paola, Raffaele De Risi

  15. Reliability of informal settlements Example Flood hazard TR=100years Fatemeh Jalayer, Francesco De Paola, Raffaele De Risi

  16. Reliability of informal settlements Example Flood hazard TR=200years Fatemeh Jalayer, Francesco De Paola, Raffaele De Risi

  17. Reliability of informal settlements Example Flood hazard TR=500years Fatemeh Jalayer, Francesco De Paola, Raffaele De Risi

  18. Reliability of informal settlements Example Flood hazard For a given grid point Fatemeh Jalayer, Francesco De Paola, Raffaele De Risi

  19. Reliability of informal settlements Example Flood hazard For a given grid point Fatemeh Jalayer, Francesco De Paola, Raffaele De Risi

  20. Reliability of informal settlements Example Vulnerability ∙ Hazard Fatemeh Jalayer, Francesco De Paola, Raffaele De Risi

  21. Reliability of informal settlements Class of structures BUILDING TYPOLOGY IDENTIFICATION N Buildings Ntype,1 Type,1 - the construction techniques       - the method used for constructing the bricks       - type of the mortar used       - presence or absence of lintel beams       - foundation type and height from the ground       - the existence of drainage system       - the material used for roof beams       - the material used for roof cover       - type and number of openings       - the division of internal spaces       - possible reinforcing used in the wall corners       - the techniques used for anchorage of roof inside the wall       - general geometrical characteristics y Informal settlements Ntype,2 Type,2 … … Ntype,i Type,i … … Ntype,k Type,k x Fatemeh Jalayer, Francesco De Paola, Raffaele De Risi

  22. Reliability of informal settlements Class of structures ( TYPE 1; TYPE 2; …; TYPE i; …; TYPE k) • Into Typeiit’s possible to study n structures with a particular mechanical procedure trough that are recognized m collapse (survey sampling). • The target is to evaluate the collapse probability based on survey sampling given the information (flood height and structural typology). 1 with probability Pi 1 Binomial distribution 0 with probability 1 -Pi h* h (m) Fatemeh Jalayer, Francesco De Paola, Raffaele De Risi

  23. Reliability of informal settlements Class of structures Beta distribution Normalization factor Likelihood: binomial distribution Prior distribution: uniform • For the evaluation of Pi it’s possible to calculate the expected value: Fatemeh Jalayer, Francesco De Paola, Raffaele De Risi

  24. Reliability of informal settlements Class of structures Example • TYPE 1  2collapse on 5 buildings • TYPE 2  5 collapse on 6 buildings • TYPE 3  3 collapse on 7 buildings survey sampling on 18 buildings • Expected value • P1 0.4286s=0.0306 • P2 0.7499 s=0.0208 • P3 0.4444s=0.0247 P  0.542 Fatemeh Jalayer, Francesco De Paola, Raffaele De Risi

  25. Reliability of a network For the networks and lifelines, generally definable like system spatially distributed, the reliability can be obtained considering the conditions of the single part of the system (logic structure) and is function of the target that we want to achieve. Than it’s important to know: Detailed description of the network Position of the network respect to hazard sources I1 1 O1 Ii Input point into the network Oi Output point into the network 2 3 4 i Network element Element centroid Possible direction I2 O2 5 Fatemeh Jalayer, Francesco De Paola, Raffaele De Risi

  26. The network components Roads (paved and unpaved) Bridges Critical nodes Point of interest (e.g. schools, Emergency services, hospital) Open public concentration areas Parking areas Tunnel Culverts Side drainage ditches Understrains storm drains Sewage system …

  27. Reliability of a network Vulnerability of the single part Functionality target • ONE to ANY • ANY to ANY Fatemeh Jalayer, Francesco De Paola, Raffaele De Risi

  28. Reliability of a network • p(hrain) represents hazard • P(D/C>1|hrain) is the • component fragility 1 h* h (m) The vulnerability of a road network component can also be defined in terms of its lack of connectivity or failure: Fatemeh Jalayer, Francesco De Paola, Raffaele De Risi

  29. From component to system The system vulnerability is calculated as a function of vulnerabilities for different structural types within the system (e.g., using cutset theory). Fatemeh Jalayer, Francesco De Paola, Raffaele De Risi

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