Wednesday, July 28, 2021

Community Based Seismic Retrofitting Program for Disaster Risk Reduction

Seismic retrofitting improves community resilience on housing. Even it is smaller activities compare to the post-disaster reconstruction. It is still workable even during Covid-19 pandemic on reducing earthquake risk on densely populated houses. This writing is based on retrofitting program implemented by Indonesian Red Cross and supported by the American Red Cross and Build Change, and funded by USAID. The program takes place in Indonesia at a city and at a sub-district which are located at earthquake prone area.

Many houses were poorly built in the earthquake prone area; therefore, they are in vulnerable state. Homeowners might not realize that they are at risk until earthquake with certain magnitude occurs. Their houses might collapse or might have significant damage. Therefore, these houses need to be seismically strengthened as a disaster risk reduction measure. In densely populated community this initiative become more crucial since large-scale houses might collapse if earthquake occur. Moreover, the debris might block their narrow evacuation route. Even retrofitting is less expensive compared to the rebuilding cost, but due to unavailability of funding more people reluctant to retrofit their houses.  During the program implementation, several initiatives have been taken to promote seismic retrofitting and strengthened with the community engagement initiatives. All of these are to create retrofitting demand at community level.

Seismic retrofitting and disaster risk reduction

Photo: Retrofitting with conventional method

Seismic retrofitting is to modify the existing structures to make them more resistant to the seismic activity due to the earthquakes. After the retrofitting, the structure could be damaged by the earthquake at certain elements such as beams but must not catastrophically collapse. Retrofitted house might prevent sudden failure which might cause its dwellers get injured. Seismic retrofitting can be done either in recovery or in preparedness setting. But to carry it out under homeowners’ initiative on preparedness setting is bit difficult compare on post-disaster recovery. During recovery process the house owners have the urgency to repair and retrofit their houses. On the other hand, without disaster occurrence homeowners tend to put retrofitting below other priorities.

There are similarities whether it is in recovery context and preparedness setting. Retrofitting is intended not to demolish the house but to strengthen it. It is the cost, to begin with. Cost-benefit assessment is used to evaluate the effectiveness of various seismic retrofit strategies to address concerns about earthquake safety and damage to older concrete frame buildings. When houses evaluated on the basis of repair costs only, the maximum cost of retrofit measures that offer a positive rate of return is 10% to 30% of the building replacement value.[i] Secondly, retrofit need skilled masons and under experienced technical person supervision. It is because seismic retrofitting need’s structure evaluation to check its vulnerability, design and then the construction work itself.

Since the cost is less than to construct from foundation to the roof, retrofitting can be implemented in every economic situation. During economic slowdown, retrofitting provides important contribution to the local economy. The construction work will provide job for builders and workers from other related sectors. Even it is a small-scale activity compared to the common construction work, the construction process needs inputs from other industries and production factors. This could generate considerable employment through multiplier effects.[ii] But its impact on the economy still depends on the volume of the retrofitting work within the area. The bigger the demand it will bring more resources and increase in economic activities. Moreover, the retrofitting cost might even less than 30%, if the activities reach economies of scale.

Naturally construction works always need time to reach the pace and amount of work of economies of scale. Surely kickstart always not easy and simple. It needs preparation such as training for builders, construction material provision, structure assessment and lastly homeowner confidence on retrofitting. Therefore, to ensure the retrofitting program can be implemented those for aspects should be prepared. In this writing, as it will be focused on the community engagement.

Challenges on proper construction and retrofitting

In every country the Government issued Building Codes that the people need to follow to ensure that they can have robust and earthquake resistant structure. The code also available for structural elements such as beam, column and foundation. The code also expected to be a guidance for design and prerequisite to get building permit. But the challenge is on the compliance. In the developing world, the compliance mostly only happens at multi story buildings not at one or two story landed houses. The situation even more challenging in the rural since the monitoring for compliance and enforcement is quite rare. In most countries, house builders or masons do not think that they are responsible for the vulnerability or collapse of the houses they constructed[iii].

Brick gable wall without concrete frame

Photo: Brick gabble wall without concrete frame

In rural area construction practices are far different from the code. The builders are confident about the safety of the houses which they constructed although most of builders do not know the building codes[iv]. For instance, in a village in in Sukabumi, West Java, Indonesia the houses have no columns. The builders laid the brick at the stretcher face not at their bed. Besides of the ignorance of the codes, people done this because they want to save money by putting less brick. Another example is how the homeowners and builders construct brick gable wall. Since concrete structure is being considered costly, the builders constructed it without concrete frame which make their houses are quite vulnerable when the earthquake occur. The risks are when the earthquake occurs, the brick gable wall might fall off. Surely it can endanger the house owner since it is catastrophic.

Ignorance of the Building Codes is the first barrier to have safe structure. The next barrier is the economic cost of retrofitting. Currently, retrofitting is at the supply driven rather than demand driven as homeowners are heavily dependent on grant or financial incentives. homeowners are unwilling to invest in their house as the house is not a source of income for them and seismic safety is not a priority for them.[v]

If the people are willing put themselves at risks by putting no column at the wall it will be difficult to persuade them to retrofit their house. Some people put the retrofitting at lower priorities then other needs, even though they received the information on earthquake risks. Earthquake is not always occurred regularly like flooding which has seasonal occurrence. People easily forgotten. Even if people have sufficient money, they want to enlarge the houses or just put new paint in their houses.

Another challenge on retrofitting is unavailability skilled builders and proper construction material which need to be used in retrofitting. This can be easily understood since retrofitting is not common in the area therefore it is difficult to find builders which have retrofitting skills. Also, if most of the houses in the area were built without following the Building Code, then it is difficult to find construction material as directed in the code, for instance on using steel deformed rebar. Steel deformed rebar is prerequisite for earthquake resistance reinforced concrete structure. In those area, the demand for deformed rebar is less than the smooth rebar, hence the deformed rebar become expensive.

Creating the demand for retrofitting

Provision of skilled builders and retrofitting material is directly proportional to the demand for retrofitting. The more people want to retrofit their houses the more builders come and work in the area. New builders will be introduced to the retrofitting technique by the skilled builders, as they will work as an intern. More construction material will be available due to the needs of ongoing retrofitting work. Then how to increase the retrofitting demand?

Photo: Retrofitted house using Ferrocement technique which developed by Dr. Teddy Boen

The recent development, many retrofit strategies are feasible and several traditional and innovative options are available to engineers[vi]. There are research and studies on retrofitting which can be implemented on using available material and with affordable price. For instance, ferrocement[vii] technique which developed by Dr. Teddy Boen, can be implemented with simple technique and at an affordable cost. And depends on the needs, homeowners also have the option on choosing conventional method by adding seismic resistance attribute to particular structural element.

Other than the engineering approaches is the encouragement with social language using the positive messages, i.e. homeowners are crucial to be convinced that the investment in safer housing will eventually prove to be worthwhile.[viii] On the other hand from the negative messages, it is also important to increase disaster imagination of the people to understand the importance of seismic retrofit of weaker houses that is the main cause of casualty and to create some social systems by which homeowners are encouraged to retrofit their own weaker houses by themselves.[ix] These initiatives should carried out by trained community volunteers.[x]

Other initiatives to create demand is through connecting the people with the banking institution. Some of banks have financial loan for house renovation but they do not have loan for retrofitting. The bank has been approached and currently is calculating the potential market and benefit of the loan program.

Currently Indonesian Red Cross is developing strategic level collaboration with the Public Works and Housing, to re-shape the government program. It is expected that the current house renovation program which funded by government can be changed to house retrofitting. More retrofitted houses also mean more training opportunity for the builders.


Photo: Training of community volunteers to equipped them on their role as Retrofitting Agents. 

Another campaign done by the trained community volunteers who are using the retrofitted houses as retrofitting showcase. People invited to visit the houses, discuss with the homeowners and trained community volunteers. This campaign was launched to create bandwagon effect in the community. The Community Volunteers acted as Retrofitting Agent visited homeowners door-to-door sending the messages of retrofitting. 

Still, more effort needs to be made. Supply chain is one important area need to be developed. The need of affordable construction and retrofitting material such as deformed bar, wire mesh, Polypropylene (PP) bands or fiber-reinforced paint should be available in local shop. At the end it will reduce the cost.

Collaboration with other humanitarian organization program, such as livelihood and others, need to be developed. Improved quality of living of the society will increase homeowners’ capacities and then at the end they may retrofit their houses.

All of these should be seen as approaches which can strengthen the community effort, since the retrofitting awareness should be a bottom-up initiatives. Homeowners who eventually aware on earthquake risk reduction should be able to connect with available retrofitting resources. Then at the end the retrofitting can be implemented and initiated by the community.

 Arwin Soelaksono



[i] Liel, Abbie & Deierlein, Gregory. (2013). Cost-Benefit Evaluation of Seismic Risk Mitigation Alternatives for Older Concrete Frame Buildings. Earthquake Spectra. 29. 1391-1411. 10.1193/030911EQS040M.

[ii] Wibowo, M. Agung. The Contribution of The Construction Industry to the Economy of Indonesia: A Systemic Approach (2009)

[iii] Okazaki, K and T. Saito.   Seismic Risk Perception Concerning Non-engineered Houses (2012)

[iv] ibid.

[v] Build Change, 2019.

[vi] Zerbin, Matteo . et. al. Sustainable retrofit design of RC frames evaluated for different seismic demand (2015)

[vii] Boen, Teddy. Retrofit Bangunan Yang Rusak Akibat Gempa , 2015, 2019 https://www.teddyboen.com/Retrofit_Bangunan_yang_Rusak_akibat_Gempa.html

[viii] Okazaki, Kenji et. al. Study on willingness of the residents in seismic retrofitting of the house - comparison among Indonesia, Nepal, Pakistan, Turkey, The Philippines, Fiji, and Japan

[ix] Sathiparan, Navaratnarajah. Mesh type seismic retrofitting for masonry structures: critical issues and possible strategies. European Journal of Environmental and Civil Engineering. Volume 19, 2015

[x] In Indonesian Red Cross (PMI) program, supported by the American Red Cross and Build Change and funded by the USAID, the trained community volunteers (known as Community Based Action Team) acted as Retrofitting Agents. They have been trained how to spot vulnerabilities, provide retrofitting option and solution including calculating retrofitting budget. On their role the Retrofitting Agents are equipped by Retrofitting field guide the help them during house visits and encourage their neighbors to retrofit their houses.

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