Contents■ Report on Buildings and Houses Damaged by the Jogjakarta Earthquake, Indonesia on June 27, 2006
■ Toward the Establishment of Safe and Secure Regional Communities against Disasters■ Revising the Guideline for Designing Gentle Slope-type Coastal Dikes■ The English Version of “2006 Annual Report of NILIM” is now on our website

No.18
September 2006

News Letter

ISSN 0389-4150■ Report on Buildings and Houses Damaged by the Jogjakarta Earthquake, Indonesia on June 27, 2006
Housing Production Division
1. Introduction
An earthquake with magnitude (USGS*1) MW = 6.2,
depth 17 km; (BMG, Indonesia*2) Mb = 5.9, depth
11.87 km took place inland in the center of the islandof Java in the Republic of Indonesia at 5.54 a.m. local
time on May 27, 2006. A large number of houses collapsed in the special province of Jogjakarta and Central Java province, causing many deaths and injuries(Tables 1 and 2). The total numbers of deaths, injuries
and refugees were 5,778, 37,883, and 2,111,872 respectively (Source: Media Centre and Bakornas, June27, 2006). Those areas that suffered heavy damage
had high population densities.
In connection with this earthquake, NILIM carriedout a field survey between June 6-12, 2006. During
the survey, NILIM was accompanied by a JICA*3

Team. The aim of the survey was to observe the damage to houses and buildings caused by the earthquake. Through the observation results, technology
improvements and restoration and reconstruction
techniques can be developed. The survey was carriedout in the severely damaged area around Jogjakarta
city and its districts such as Bantul, Gunungkidul
and Sleman in the special province of Jogjakarta, andone district in the Central Java province, Klaten (Fig.
1). The buildings surveyed included public buildings,
commercial buildings and houses. This report focuses
on damage to houses and buildings.
*1 USGS: U.S. Geological Survey*2 BMG,Indonesia: The Meteorological and Geophysical Agency of Indonesia*3 JICA: Japan International Cooperation Agency

Table 1 Data of damage to government buildings

Central Java Province

SlemanKlatenJogjakarta
Bantul★ Epicenter (USGS*1)
Jogjakarta Province★ Epicenter (BMG*2)

Java Island

Fig. 1 Map of the disaster area

JOGJAKARTA PROVINCE
Bantul district
Sleman districtKulon Progo district
Jogjakarta district
Gunung Kidul district
SUB TOTALCENTRAL JAVA PROVINCE
Klaten district
Boyolali district
Magelang district
Purworejo district
Sukoharjo district
Wonogiri district
SUB TOTAL
TOTAL

Heavy
39
120
159

Medium-Light
57
57

76
56
625
163
322

430
236
14482
482

439
160
7507
564

Source: Media Center DIJ: June 27, 2006

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News Letter

Table 2 Data of damage to school buildings

JOGJAKARTA PROVINCE
Bantul district
Sleman district
Kulon Progo district
Jogjakarta district
Gunung Kidul district
SUB TOTALCENTRAL JAVA PROVINCE
Klaten district
Boyolali district
Magelang district
Purworejo district
Sukoharjo district
Wonogiri district
SUB TOTAL
TOTAL

Heavy
71,763
19,113
4,685
6,085
7,454
109,100

Medium
71,372
27,6878,430
5,408
11,033
123,930

Light
73,66949,065
9,672
15,364
27,218
174,988

29,988
307
386
10
51
17
30,759139,859

62,979
696
386
214
1,808
12
66,095
190,025

98,552
708
546
780
2,476
74
103,136
278,124

Source: Media Center DIJ: June 27, 2006

2. General damage to masonry houses and reinforced concrete buildings1) Masonry houses(1) Features of masonry houses
The most common type of housing in this area is single-story masonry houses. In accordance with the tropical climate, houses are characterized by their highfloors and large openings. In the disaster area, most of
the housing can be categorized as “non-engineeredconstruction”, meaning housing not constructed according to common architectural and structural standards. The bricks used for masonry houses are handmade and fired by using rice husks and wood (measured brick size: 95×210×45mm, 115×245×45mm,120×255×45mm). These bricks are usually used forany kind of buildings or houses. Roofs are generally
the wooden roof truss type, and tiled roofs are constructed without any roof boards.
(2)Unreinforced masonry houses and damage to them
The masonry walls of old and traditional houses aremainly unreinforced masonry structures, in which themortar bed is generally made of mud and lime; pozzolanic sand and lime; or red brick powder and lime, owing to the high price of cement. This combination material causes a low bonding strength between bricks
and mortar, which could be the main damage factor as
so many people were killed or seriously injured by theearthquake due to the shear or out-of-plane rupture

Photo 1 Damage to unreinforced concrete building

mechanism. Another cause of damage was rupture of
the roof frame and its roof cover (Photo 1).
(3) Reinforced masonry houses and damage to themMasonry houses constructed in recent years havebeen strengthened by an additional reinforced concrete
frame surrounding the masonry wall. Recently, somestructures of this type have been built by structural
engineers, foremen and technicians. In these houses,
cement and river sand are used for the mortar bed onlaid bricks. The perimeter of the masonry walls isstrengthened by reinforced concrete and the wall surfaces are finished with cement mortar. Observations
showed that not many houses of this type experienced
severe damage. However, many houses collapsed orwere irreparably damaged due to insufficient bar arrangement of the joint sections of the tie beams andcolumns and due to imperfect masonry work. It istherefore very important to improve the technology related to this type of structure in this particular area.
2) Reinforced concrete structures and damage tothem(1) Reinforced concrete rigid frame structures are used
for schools, public buildings, and commercial buildings. In the case of reinforced concrete structures,
hand-made bricks and hollow concrete blocks are used
for partition walls as well as for external walls. These
are known as infill walls and are used as non-structural walls.
(2) The earthquake caused typical damage such as
shear failure and out-of-plane rupture of the infillwalls, and hence building collapse leading to death andinjury (Photo 2).

Photo 2 Damage to reinforced concrete building

Observation of the structural conditions of the reinforced walls that collapsed (shear failure and out-ofplane damage) showed that the failure was due to incorrect bar arrangement of the practical columns of
the walls and large wall openings.
It is necessary to consider the structural details of
the design and building construction methods thatwould ensure infill walls of buildings do not collapse inorder to prevent human injury.
(3) Many reinforced concrete structures were damaged
and collapsed during the observation. The main causesof the damage and collapse for reinforced concretebuildings were the building configuration, structuralperformance (effect of the infill walls), and the qualityof the materials and building construction. Thus, it ishard to identify a single cause of building damage orcollapse.
The detailing of the stirrups with 90-degree hooks on
reinforced concrete columns were observed to havecaused shear failure on those buildings that collapsed.
This type of stirrup detailing does not comply with theIndonesian Earthquake Resistance Building Code. It isconsidered that if buildings had strictly followed the135-degree hook bar detailing as mentioned in theCode, perhaps some buildings might not have collapsed, and failure or damage would have been prevented.
3. Conclusions
The Central Java Earthquake caused many deaths
and injuries resulting from the collapse of houses
mainly caused by the vibration. The houses that completely or partially collapsed included those with unreinforced masonry structures and masonry buildings
constructed recently. However, it should be observedthat there were several houses with reinforced masonry structures that remained without severe damage.
The important points that will need to be consideredwhen restoring or constructing new housing are as follows:
1) The lessons learned from this earthquake need to beconsidered for housing and building construction in

the future.
2) When planning the restoration of housing, a housing design consultation bureau needs to be established in order for houses or building owners to get
advice on building restoration for single-story extension-type housing by implementing reinforced masonry techniques.
3) Foremen, technicians and engineers should betrained to understand the meaning of strengthening
masonry walls and must be given technical information on methods of arranging reinforcement.
4) Regular workshops in connection with on-site testing methods for confirming the quality of masonrywalls should be organized in cooperation with related institutions.
The above improvements would lead to better construction quality, and lead to the creation of municipalities, regions and a nation that is more resistant todisasters affecting houses, buildings and infrastructure facilities (Fig. 2).
Confinement Column
Inner beam

Light Material (Wood Bamboo)

Column and Beam Connection
Should Bar anchoring

Fig. 2 Improvement of reinforced masonry house construction■ Toward the Establishment of Safe and Secure Regional Communities against Disasters
Planning and Research Administration Department
1. Introduction
Japan, which has suffered and recovered from various kinds of disasters, has continuously implemented
diverse safety measures, which have greatly improved
the safety of communities. Such efforts must be continued in the future.
However, the country still suffers much human andproperty damage every year, and new threats to safetyoccurred surfaced. Dramatic technological advances
are needed in addition to cooperation with human andsocial sciences in orderto enhance the capacityof society to resist dangerous phenomena andconstruct safe and secure infrastructures thatenable people to enjoy a
Photo1 Rescuing pupils from thehigh quality of life.
isolated elementary school on theWith such a back- next day (Niigata flood in July 2004)
ground, we propose thedirections for safety efforts in Japan, which were decided by referring to those in the United States. We hopethat this proposal will be used to develop a core ofshared understanding, which will serve as the basis ofmeasures for all parties involved.

2. What are safe and secure communities?
By referring to “Grand Challenges for Disaster Reduction” of the United States and reports by the Working
Group on Science and Technology Policy for a Safe andSecure Society established by the Ministry of Education, Culture, Sports, Science and Technology, we decided to implement the following three basic points inour studies on the directions of safety measures in Japan:1) Investigate safety and secure issues from the viewpoint of regional communities,2) Comprehensively investigate what should be done,and3) Develop shared recognition among all parties involved and consider it as a process of constantly understanding the actual states and spreading collaboration.
Based on this recognition, the first task was to identify what constitutes a safe and secure community.
Then, concrete methods should be developed for all parties involved to jointly construct and sustain safe andsecure regional communities, which:1) Have maximum potential for saving human life,2) Are resistant against dangerous phenomena, and
3) Can quickly recover from damaged states.

3. Directions of measures (draft)
The policies of the measures (draft) for constructing
communities that satisfy the aforementioned conditions
are summarized as the “Ten challenges” in Table 1.
The draft has been prepared based on the conceptthat all parties involved should share the same recognition based on present states and collaborate with eachother. To attain this goal, the Ministry of Land, Infrastructure and Transport needs to encourage the parties to collaborate, and the draft states the contents
and directions of the measures to be taken by its development bureaus.

2) Executing the challenges mainly by the regional development bureaus of the Ministry of Land, Infrastructure and Transport by encouraging as many parties as
possible to collaborate, such as residents, regional communities, municipal governments, infrastructure managers, private companies, and economic communities.

Table 1 Ten challenges
Classification

Ten challenges

1. Knowledge

1-1 Learning from disasters
1-2 Supporting communications that lead to risk-preventive behavior
1-3 Assessing the effects on the economy and business activities ina disaster-stricken region

2. Cooperation

4. Conclusion
We propose the measures for constructing safe andsecure regional communities against disasters in theform of “Ten challenges” based on the actual states ofthis country. Future actions will include:
1) Establishing concrete contents of the challenges,
and

2-1 Sharing information and knowledge with regional communities
even under normal circumstances
2-2 Promoting the creation of communities, which are capable ofdisaster prevention through self-support and mutual-support

3. Real-time
information

3-1 Providing information in real time

4. Recovery

4-1 Improving the resistance and recovery power of basic
infrastructures as a whole

3-2 Utilizing emergency earthquake information

4-2 Developing innovative technologies to improve the resistance offacilities
4-3 Preparing for recovery■ Revising the Guideline for Designing Gentle Slope-type Coastal Dikes
Coast Division
The Guideline for Designing Gentle Slope-type
Dikes was revised jointly by the Coast Division ofthe River Bureau and the Coast Division of the River
Department, National Institute for Land and Infrastructure Management.
A dike which has a slope gentler than 1:3 reduces
the run-up height of waves and enables access tobeaches. Thus, the Guideline for Designing Gentle
Slope-type Dikes was issued in 1989, encouraging
the construction of gentle slope-type dikes to promote shore protection and coast utilization.
Gentle slope-type dikes have been reported to cover large areas of beaches since they have long sectional bases, destroying the habitats of marine organisms and impeding the use of the beach. Since
most gentle slope-type dikes were constructed on
the sea side of existing steep slope-type dikes, thefootings are located under the sea and cause waves
to run up higher than in steep slope-type dikes.

Thus, the revised guideline clarifies the range ofapplication; for instance, it requires footings to beconstructed above the low-water level and advises
reconsideration of the construction of gentle slopetype dikes when the width of the beach may become
narrower than 20 m after the construction due tocoastal erosion or other causes, and to use alternative measures, such as constructing steep-slope
banks.
In the revised guideline, performance-based
standards were introduced to enable engineers in
the field to devise measures, and coordination
among coastal protection, environment, and utilization was set as the goal of the Coast Law in 1999.
Points to note regarding the environment are also
included. In addition, new knowledge, such as to assess whether a gentle-slope bank accelerates orcurbs erosion, as well as safety and performance assessment methods were added.

■ The English Version of “2006 Annual Report of NILIM” is now on our website
aaWe publish the English Version of “2006 Annual Report of NILIM” to show our research activities andaccomplishments, and you can see all of contents on our website, www.nilim.go.jp.

National Institute for Land and Infrastructure Management
Ministry of Land, Infrastructure and Transport
Asahi 1, Tsukuba, Ibaraki, 305-0804, Japan(Tachihara) Tachihara 1, Tsukuba, Ibaraki, 305-0802, Japan(Yokosuka) Nagase 3-1-1, Yokosuka, Kanagawa, 239-0826, Japan
TEL:+81-29-864-2675 FAX:+81-29-864-4322

News Letter

No.18

September 2006w w w . n i l i m . g o . j p