The recent 7.7-magnitude earthquake that struck Myanmar has left a devastating impact, with over 1,600 confirmed dead and thousands injured. While Myanmar bore the brunt of the destruction, neighbouring Thailand also witnessed significant damage, particularly in Bangkok, where a high-rise under construction collapsed, killing at least 10 people. The collapse has raised serious concerns about the structural integrity of skyscrapers in Thailand and their vulnerability to seismic activity.
The earthquake, which struck near Mandalay, sent tremors through Thailand, with the greater Bangkok area experiencing significant shaking. The collapse of the high-rise near Chatuchak market has sparked questions about whether Thailand’s skyscrapers are adequately designed to withstand earthquakes.
Experts say Thailand’s skyscrapers, particularly in Bangkok, are at risk due to a combination of outdated construction standards and the city’s geological conditions. Amorn Pimarnmas, president of the Structural Engineers Association of Thailand, told the BBC that fewer than 10% of buildings in Bangkok are earthquake-resistant. Although a 2007 law mandates earthquake-resistant designs for new buildings, older structures remain highly vulnerable. Many of these older high-rises were primarily designed to handle wind loads rather than seismic forces, making their ability to withstand quakes uncertain.
Compounding the problem is Bangkok’s soft soil, which can amplify ground shaking by three to four times. This effect increases the risk of structural failure, particularly for medium-rise buildings between 10 and 20 storeys, which are more susceptible to resonance effects caused by seismic waves.
Potential risks to high-rises
Experts highlight several factors that could make Thailand’s skyscrapers vulnerable:
- Soft Soil Foundation: Bangkok’s soft clay soil can amplify seismic waves, increasing the risk of structural damage.
- Ageing Infrastructure: Many high-rise buildings were built before modern earthquake-resistant codes were introduced.
- Lack of Retrofitting: Some older structures may not have undergone necessary reinforcements to withstand earthquakes.
The British Chamber of Commerce in Thailand had earlier highlighted that Bangkok, though classified as a low seismic risk area, is not immune to earthquake hazards. Past events, such as the 9.1-magnitude Sumatra-Andaman earthquake in 2004 and the 6.8-magnitude Burma earthquake in 2011, demonstrated that tremors could still cause structural damage in Thailand.
The 2007 seismic design regulations require buildings taller than 15 metres to be earthquake-resistant. However, implementation has been inconsistent, and many older buildings remain at risk. According to Dr Chusilp, designing medium-rise buildings for earthquakes increases structural costs by 10-15%, which may have deterred developers from upgrading existing structures.
