Measures to Formulate Disasterresilient City in TMG

Disaster Management Urban Development Section
Urban Development Projects Division
Bureau of Urban Development

Today’s Topics
1. Densely-built Wooden
House Area
2. District-based Assessmentof Vulnerability toEarthquake Disaster3. Disaster-resilient City
Promotional Plan2

Densely-built Wooden
House Area
Distribution and Existing
Condition of the Area
Characteristics of the Area
3

Vulnerability to Earthquake
Fire Spread

Building Collapse

Great Hanshin-Awaji Earthquake (17 January 1995, M.7.3)
・Missing/Death: 6,437 persons ・Damage of Building: 249,180 buildings4Distribution of Densely-built Wooden House
Area
Within 23 Wards Area:
Apx.16,000ha(25% of Areas of 23 Wards)

Aged wooden houses are densely
distributed in outside of JR Yamanote
Line in doughnut shape

JR Chuo Line

JR Yamanote Line5

Existing Condition of Densely-built Wooden
House Area

Examples of Existing Condition
6

Existing Condition of Densely-built Wooden
House Area

Examples of Existing Condition

7

Characteristics of Densely-built Wooden
House Area
Densely Built Wooden House Area
Aged Wooden
HousesTime to be Renewed• Aged owners• Narrow and small lots• Impossible to fulfill current building standards law
in terms of attachment to the road

Constraints on the Renewal
8District-based Assessment ofVulnerability to Earthquake
DisasterDamage Estimation for an Earthquake
Directly underneath Tokyo
Survey of District-based Vulnerability
to Earthquake Disaster9

Damage Estimation for an Earthquake
Directly underneath Tokyo
Magnitude
Time &Season

Scenario

Northern Tokyo Bay Earthquake,
M7.3
Winter Morning,
5:00

Cause
Cause

PhysicalDamages(buildings)

Winter Evening,
18:00

WinterMorning, 5:00

8m/s

Wind Speed

HumanDamages(persons)

Winter Noon,
12:00

Tama Directly underneath
Earthquake, M7.3
Winter Noon,
12:00

Winter Evening,
18:00

8m/s

Death

7,649

6,296

9,641

5,115

3,546

4,732

Building
Collapse by
Liquefaction

6,927

4,972

5,378

4,489

2,840

3,220

Earthquake
Fire

540

1,138

4,081

403

496

1,302

Others

182

253

186

223

210

210

Building
Damage136,297

166,906

304,300

90,947

99,788

139,436

Building
Collapse by
Liquefaction

116,224

116,224

116,224

75,66875,66875,668Earthquake
Fire21,24054,417201,249

15,707

24,811

65,770Source: Damage Estimation for an Earthquake Directly underneath Tokyo, TMG Disaster Management Committee, April 201210

Damage Estimation for an Earthquake
Directly underneath Tokyo
Distribution of the number of totally collapsed buildings by tremorand liquefaction (Northern Tokyo Bay Earthquake, M7.3）

Number of Totally Collapsed Buildings
100－400
50－10025－ 50
10－ 25
2－ 100－ 2

11Damage Estimation for an Earthquake
Directly underneath Tokyo
Distribution of the number of destructed buildings by fire (Northern Tokyo
Bay Earthquake, M7.3, Winter Evening, 18:00, Wind Speed: 8 m/s）

Number of Destructed Building by Fire
100－50－100
20－ 50
10－ 20
1－ 100－ 1012

District-based Assessment of Vulnerability toEarthquake Disaster
Objectives- To grasp the highly vulnerable areas to earthquake
To decide priority project areas- To deepen the recognition to seismic disaster of thecitizen of Tokyo and strengthen awareness of disastermanagement
Contents- To compare the vulnerabilities by district under same
earthquake scenarios- To assess by district- To implement once a five-years
 Vulnerability to Building Collapse
 Vulnerability to Fire Integrated Vulnerability

13

District-based Assessment of Vulnerability toEarthquake Disaster
Survey Work Flow

Vulnerability toBuilding Collapse

Vulnerability toFireIntegrated Vulnerability

14

Vulnerability to Building Collapse(1) Characteristics of ground structure1) Classification of ground structure by district
2) Increment ratio by type of ground structure(2) Characteristics of building
1) Number of buildings by structure and age2) Damage ratio by type of building

15

Classification of Ground Structure

16

District-based Assessment of Vulnerability toEarthquake Disaster
Vulnerability to Building Collapse●５●４●３●２●１HighLow

17Vulnerability to Fire
(1) Vulnerability to fire breakout
1) Maximum number of fire breakout by
season and time(2) Vulnerability to fire spread (fire spreadsimulation)
1) Number of totally destructed buildings within
6 hours2) Number of catch fire from neighboringdistricts18

District-based Assessment of Vulnerability toEarthquake Disaster
Vulnerability to Fire

●５●４●３●２●１HighLow

19Integrated Vulnerability
Vulnerability to Building Collapse (Rank)+Vulnerability to Fire (Rank)

Relative rating on a scale of 1 to 520

District-based Assessment of Vulnerability toEarthquake DisasterIntegrated Vulnerability●５●４●３●２●１HighLow
21Disaster-resilient City
Promotional Plan
Basic Concept of Disaster-resilient City
Formation of Fire Spread Prevention Belt
Fire-resistant of Urban Area22

Disaster-resilient City Promotion Plan
Great Hanshin-Awaji Earthquake (Jan. 1995)→ Established in 1995
→ Amended in 2003
→ Amended in 2009
(1) Objective

 To prepare for the earthquake disaster and to preventthe expansion of damages, the buildings and urban
facilities should be secured their resilience toearthquake and fire, and various measures regarding
improvement of urban structure should be promoted.

(2) Target Area

23 Wards and 7 Cities in Tama Region (Densely-built
Wooden House Areas)* Including all the emergency transportation roads within TMG(3) Structure and Basic Plan
: 2009～2025 (17 years)
Planning
Implementation Program: 2009～2015 (7 years)
Period23

Promotion Plan of a Disaster-prepared City
Basic Concept of Disaster-resilient City Formation of Fire
Spread Prevention
Belt
Living Area of Disaster
Management

 Development of urban
planning arterial road
 Fire-resistant of buildings
along the designated roads Fire-resistant of Urban Area
 Implementation of neighboring
community roads development
 Secure of open space for disastermanagement Fire-resistant and retrofit of buildings24Formation of Fire Spread Prevention Belt
Concept of Fire Spread
Prevention Belt

Urban Area inside of Disaster
Management Neighboring Block
Fire-resistantBuildings• Fire-resistant of Building• Secure of Open Space• Road Development

Urban Planning
Arterial Road
Disaster Management
Neighboring Block

Disaster Management
Neighboring Block

Fire Spread Prevention Belt
To secure the safety of adjacent Disaster
Management Neighboring Block

Secure the safety inside ofDisaster Management
Neighboring Block

Prevention of largely spreadfire in the urban area at thedisaster event25Formation of Fire Spread Prevention BeltCriterion of Fire Spread Prevention Belt

Road Width (m)Fire-resistant Ratio ofBuildings along theDesignated Roads

More than 27---24 – 27

More than 40%

16 – 24More than 60%

11 – 16More than 80%
26

Formation of Fire Spread Prevention Belt
Definition of Fire
Spread Prevention
Belt● Main Axis of Disaster
Management (3~4 km mesh)
Major Arterial Roads, River with WideRiver Width● Major Fire Spread Prevention
Belt (2km mesh)
Arterial Roads● General Fire Spread Prevention
Belt (1km mesh)
The other roads and rivers27

Fire-resistant of Urban Area
• Ranking Map of Vulnerability toBuilding Collapse (6th Survey)• Ranking Map of Vulnerability
to Fire (6th Survey)
JR Chuo LineAraRiverSumidaRiver●５ High●４●３●２●１LowRing Road No.728

Fire-resistant of Urban Area
• Fire-resistant Area Ratio (FPAR)
FRAR = Open Space Ratio + (1-OSR/100) x Fire-resistant Building Ratio (%)
Building Part
OSR: { (S+R)/T} x 100 (%)
S: Area of open space which has narrow side or radial
length of more than 10m and area of more than100m2
R: Area of road with its width of more than 6m
T: Total area of target urban area

FRR: (B/A) x 100 (%)
B: Area of fire-resistant building + Area of semi-fireresistant building x 0.8
A: Total area of building area29

Fire-resistant of Urban Area
 Fire-resistant Area Ratio (FRAR) is the indicator showing
fire-resistant ability of urban area
Destructed Ratio (%)

In case of urban area with FRAR 30%,
destructed ratio by fire exceeds 80%↓
In case of urban area with FRAR 40%,
destructed ratio by fire is reduced rapidly↓
In case FRAR exceeds 60%,
destructed ratio by fire become close to 0,
In case FRAR exceeds 70%,
destructed ratio by fire is almost 0.

In case of 10,000 buildings(100 x 100 buildings)
Example of Great HanshinAwaji Earthquake
In case of the best
ground structure
In case of the worst
ground structure

Fire-resistant Area Ratio (%)

30

aster-resilient City Promotion Plan
Designation of Project Area and Priority Project Area

ely-built Wooden House
ngs Area: 16,000haoject Area

Priority Project
Area: 2,400ha

Area: 7,000ha
1% of 23 Wards Area)
Population: 1.8 mil. pax.
0% of 23 Wards Area)

on of Project Area

Project Areang rate of integrated vulnerability

Priority Projectaster-resilient City Promotion Plan
Change of Fire-resistant Area Ratio/Completion Ratio of Fire
Spread Prevention Belt
[Fire-resistant Area Ratio](%)
1996

2006

TargetIncrease of
1996-2006

2015

2025
―

65.0

69.8

4.8

―

A r e a

48.9

56.2

7.3

―

iority Project Area

48.2

55.7

7.5

653

W a r d sr o j e c t

70[Completion Ratio of Fire Spread Prevention Ratio] (%)
Length(km)Completion Ratio
1996

Increase 0f
1996-2006

2006

Target2015

tal of Fire Spreadevention Belt

1,68055627―

Main Frame Axis

537

9093

395

Major Fire Spread
Prevention Belt

312

49

61

12―