Bangkok: Professor Dr. Amorn Pimanamas, President of the Structural Engineers Association of Thailand and a professor at the Faculty of Engineering, Kasetsart University, has raised concerns following a fatal accident involving a collapsed concrete awning of an old building in Bangkok. The city is home to numerous aging structures, particularly in the inner city, with some buildings being over a century old. While not towering in height, these structures often exhibit structural weaknesses, notably in protruding sections like balconies and awnings, which are heavy concrete surfaces sometimes used for storage.

According to Thai News Agency, engineering principles indicate that buildings generally have a lifespan of about 50-60 years, as construction materials degrade over time. This is particularly true for concrete and reinforcing steel, which were of lower quality in the past. Older concrete had a low load-bearing capacity, and the reinforcing steel used was smooth, round steel with poor adhesion to the structure. These materials deteriorate, especially when exposed to environmental conditions like sun, rain, and humidity, leading to rust.

The recent collapse of the cantilevered balcony at a shophouse on Rama IV Road is not an isolated incident. A similar awning collapse occurred in October 2015 at an old shophouse near the entrance of Soi Samran Rat in Phra Nakhon district. These incidents underscore a hidden problem, as many old buildings in Bangkok face similar structural issues.

The problem of cantilevered structure collapses can be summarized into five main factors: aging structures beyond their typical lifespan, the vulnerability of protruding features with few attachment points, weak attachment points lacking strong bracing, the placement of heavy objects on the structure, and additional extensions or protrusions. In the recent Rama IV Road incident, the collapse is likely due to the first three factors, while the role of building additions remains unconfirmed.

The issue of aging buildings represents a significant threat to public safety in Bangkok. To mitigate this risk, the Bangkok Metropolitan Administration (BMA) is urged to take systematic actions, including surveying all buildings over 50 years old and those with cantilevered structures, assessing their structural integrity, and enforcing laws to rectify any identified structural weaknesses.