The Engineering Institute of Thailand (EIT) says more than 20,000 buildings in Bangkok need to be checked for safety after the concrete awning of a building in Chatuchak district collapsed last week.
Anek Siripanichgorn, head of the EIT's civil engineering department, said maintenance is key to prolonging the life of buildings. Certain kinds of buildings, especially high-rise ones, must undergo checks by experts to have their licences approved every year.
More than 20,000 buildings that have an area of at least 10,000 square metres need to be examined, Mr Anek said. Most of them are located in traffic-congested areas, where carbon dioxide could precipitate the erosion of the buildings.
It has been found that owners of about 4,000 Bangkok buildings have been failing to send inspection reports to local authorities, he said, adding the local agencies need to force them to carry out the examination and deliver reports to ward off possible tragedy.
According to building laws, newly-built structures must undergo examination after one year, with the check repeated annually. A more thorough examination must be undertaken once every five years.
He said 12,000 bridges with a total length of 490km across the country are more than 50 years old; work is needed to reinforce them so they can handle up to 50 tonnes of weight.
The EIT is asking the Interior Ministry to issue a ministerial decree to make sure every building has a strong structure to sustain weight without requiring further maintenance, Mr Anek said. The new legislation could encourage the use of quality materials in building.
The change is expected to come into force next year, he added.
Mr Anek was speaking yesterday after the concrete awning of a building in Chatuchak collapsed last Wednesday. No one was harmed by the incident, but the building suffered extensive damage.
It is one of 19 buildings owned by the Bangkok Market Office, which later told its tenants to vacate all buildings for their own safety.
The office hired a team of engineers to assess the condition and strength of its buildings and found they were not safe to live in as the structures were weak.
Authorities held talks with tenants to inform them of the need to demolish the buildings, but some residents are insistent on staying, the office's director, Chaiyanut Jetiyanuwat, said.
Siriwat Chaichana, secretary-general of the EIT, said the awnings fell because of the weight of an accumulation of rainwater they were holding, while the rain had also eroded the structure.
No maintenance has been carried out on the building and its tenants were not aware of its damage, he said.
Buildings at risk of collapse commonly lack strong structures and were built before the 1979 Building Control Act took effect, he said.
The old buildings mainly require examinations for deterioration of structures and reinforcing steel as well as cracks, he said, insisting old buildings are not always at risk of collapsing if people living there regularly check them and bring in experts to repair damaged parts.