November 30, 2022

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

4 min read




CNN

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 earthquake-prone areas of the planet.

Since Monday’s quake, survivors have been sleeping rough or in shelters away from homes at risk of collapsing as aftershocks rocked buildings already hit by the 5.9-magnitude quake. In which at least 271 people were killed.

According to the United States Geological Survey (USGS), the earthquake’s shallow depth — just 10 kilometers (6 miles) — added to the stress on structures in West Java, where more than one million people experienced the most intense aftershocks. .

Visiting the site on Tuesday, Indonesian President Joko Widodo promised that the destroyed houses – more than 56,000 of them – would be rebuilt to make them earthquake-resistant.

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

But in a developing country where about 43% of the population lives in rural areas, largely in unsafe and poorly constructed houses, building earthquake-resistant buildings is a huge challenge.

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

A man reacts during a search for victims in a landslide-hit area after Monday's earthquake in Sianjur, West Java province, Indonesia, Nov. 22, 2022.

Indonesia, an archipelago of more than 270 million people, sits along the Ring of Fire – a band around the Pacific Ocean where most of the active volcanoes are located and most of the earthquakes occur when tectonic plates collide. collide, causing earthquakes.

At least 100 of the 271 people killed in Monday’s earthquake were children, many of whom were at school when the quake struck. Oh A 6-year-old boy Two days later he was pulled alive from the rubble of his home, but many others were not so lucky.

The earthquake shook the foundations of buildings, causing concrete structures to collapse and roofs to fly off. Most of the dead were buried or trapped under the debris, according to West Java Governor Rizwan Kamil. Others were killed by landslides.

Cleo Geda Salima said that when she heard about the earthquake, she tried to call her mother in Kogenang, Siangjur, but when she failed to answer, she biked there from her home in Bandung. Decided to go.

The journey – about 65 km (40 mi) – usually takes less than two hours. But the roads were completely blocked by landslides, making him 24.

“All the houses were covered with mud and mud,” he said. He added that she was reunited with her family who survived the earthquake.

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

An Indonesian search and rescue team retrieves bodies from destroyed buildings in Cianjur Regency, West Java Province on November 22, 2022.

In Indonesia, houses were traditionally built with organic building materials including wood, bamboo and thatched grass due to the country’s hot and humid climate.

They were considered durable houses, and mostly durable in the event of an earthquake. However, according to a 2009 study by the Architectural Science Association on post-disaster reconstruction in Indonesia, increased deforestation and the high cost of wood have forced people to choose alternative materials.

Most of the houses were built of brick and concrete, and while the facade looks modern, underneath, the construction was not put together, the study said.

Additionally, low-quality concrete and poor steel reinforcement make these structures increasingly susceptible to collapse during an earthquake — while the weight of the material causes greater injury, the report said.

A man stands near houses destroyed by an earthquake in Sianjur, West Java province, Indonesia on November 21, 2022.

Earthquake-resistant structures are designed to prevent buildings from collapsing and can work in two ways: by making buildings stronger, or by making them more flexible, so they rise above the shaking ground instead of collapsing. They slip.

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

Architect Martin Schildkamp, ​​founder and director of SmartShelter Consultancy, said his company helped build about 20 schools in earthquake-hit Pokhara, central Nepal, seven years before a major earthquake hit.

When the earthquake struck in 2015, more than 8,000 people were killed, but schools built with traditional landscaping techniques and materials, such as rubble stone masonry, did not collapse.

“Our schools have not collapsed,” he said. “They only suffered some cosmetic damage.”

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

In Nepal, many people build their houses with mud mortar, which is very brittle, Schildkamp said. “If it is completely unreinforced, there is no additional strength in the building. It is the one that will collapse very easily,” he said.

Schildkamp’s team used cement mortar and inserted horizontal beams into the structure instead of vertical ones to strengthen it.

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

We need knowledge and strategy in these countries. And we need governments to make these building codes mandatory.”

In West Java, hope is fading for more people to be pulled alive from the rubble of the earthquake.

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

While President Widodo said the government would provide compensation of up to $3,200 to owners of heavily damaged houses, many families in Sianjur lost everything. And now, they face the nearly impossible task of rebuilding.



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