Indonesia needs earthquake-resistant houses. Building them is a huge challenge


A deadly earthquake that reduced buildings to rubble West Java, Indonesia has once again exposed the dangers of living in poorly constructed homes in one of the most seismically active zones on the planet.

Since Monday’s quake, survivors have been sleeping rough or in shelters away from collapsing homes as aftershocks rock buildings already compromised by the 5.9 magnitude quake that killed at least 310 people, according to the head of the country’s National Disaster Management Agency (BNPB).

Twenty-four other people are still missing, Lt. Gen. Suharyanto said on Friday.

The shallowness of the quake – just 10 kilometers (6 miles) – added to the strain on structures in West Java, where more than a million people were exposed to very strong shaking, according to the United States Geological Survey (USGS).

Visiting the site on Tuesday, Indonesian President Joko Widodo promised that the damaged homes – more than 56,000 of them – would be rebuilt to withstand the earthquakes.

“Houses affected by this earthquake are required to use earthquake-resistant building standards by the Ministry of Public Works and Social Housing,” he said. “These earthquakes happen every 20 years. The houses must therefore be resistant to earthquakes.

But in a developing country where about 43% of the population lives in rural areas, in largely unsafe and poorly constructed homes, the task of making buildings resistant to earthquakes remains a huge challenge.

As of Thursday, more than 61,000 people were displaced, according to the National Disaster Management Agency (BNPB) – and experts say the damage could have been mitigated by proper infrastructure.

Indonesia, an archipelago of more than 270 million people, sits along the Ring of Fire – a strip around the Pacific Ocean where most active volcanoes are found and where most earthquakes occur. when tectonic plates push against each other, causing tremors.

Of the 310 people killed in Monday’s quake, at least 100 were children, many of whom were in school when the quake struck. A 6 year old boy was pulled alive from the rubble of his home two days later, but many others were not so lucky.

The earthquake shook the foundations of buildings, causing concrete structures to collapse and roofs to collapse. Photos showed broken pieces of metal, wood and bricks. Most of those killed were crushed or trapped under debris, according to West Java Governor Ridwan Kamil. Others were killed in landslides.

Cleo Gaida Salima said that upon hearing about the earthquake she tried to phone her mother in Cugenang, Cianjur, but when she did not answer she decided to drive there by motorbike from her residence in Bandung.

The journey – around 65 kilometers (40 miles) – usually takes less than two hours. But with roads completely blocked by landslides, it took him 24.

“All the houses were covered in dirt and mud,” she said, adding that she had reunited with her family who had survived the quake.

“We all cried with emotion and happiness,” she said. “Our whole family immediately fled to save themselves. The earthquake was very strong.

Indonesian search and rescue team evacuates bodies from destroyed buildings in Cianjur Regency, West Java province, November 22, 2022.

In Indonesia, houses were traditionally constructed from organic building materials such as wood, bamboo and grass thatch, due to the country’s hot and humid climate.

These were considered durable homes, and largely durable in the event of an earthquake. However, increasing deforestation and the high cost of wood have led people to choose alternative materials, according to a 2009 study of post-disaster reconstruction in Indonesia by the Architectural Science Association.

More and more houses were built of brick and concrete, and although the facade may have looked modern, underneath the construction was poorly held, according to the study.

Additionally, poor concrete quality and poor steel reinforcement make these structures increasingly susceptible to collapse during an earthquake – while causing maximum injury due to the weight of the materials, according to the report.

A man stands near damaged houses after the earthquake in Cianjur, West Java province, Indonesia, November 21, 2022.

Seismic structures are designed to protect buildings from collapsing and can work in two ways: by strengthening buildings or by making them more flexible so that they swing and glide over the shaking ground rather than sagging. ‘collapse.

Architects have been developing this technology for decades, and engineers often adapt local materials and techniques to the region.

Architect Martijn Schildkamp, ​​founder and director of Smart Shelter Consultancy, said his company helped build around 20 schools in Pokhara, in the central region of Nepal, seven years before a major earthquake.

When the earthquake struck in 2015, more than 8,000 people were killed, but schools, built using traditional techniques and materials from the landscape, such as rubble stonework, did not collapse.

“Our schools did not collapse,” he said. “They only suffered cosmetic damage.”

He said that in developed countries like Japan, knowledge, infrastructure and money are readily available to build earthquake resistant buildings, but the high cost of constructing such structures makes it more difficult in developing countries.

In Nepal, many people build their homes with mud mortar, which is very brittle, Schildkamp said. “If it is completely unreinforced, there is no additional reinforcement in the building. This is what will crumble very easily,” he said.

The Schildkamp team used cement mortar and inserted horizontal reinforcement posts into the structure to reinforce it, instead of vertical posts.

Building regulations should prevent the proliferation of poorly built structures, but in some countries governments are not doing enough to enforce the rules, Schildkamp said.

“We need knowledge and strategy in these countries. And we need governments to make those building codes mandatory,” he said.

In West Java, hope is fading of pulling more people alive from the debris of the quake.

Aftershocks are also complicating efforts, and residents now live in fear that the next disaster will topple their unstable homes again.

While President Widodo said the government would provide compensation of up to around $3,200 each to owners of badly damaged homes, many families in Cianjur lost everything. And now they face the almost impossible task of rebuilding.

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