The Thai-Belgian bridge on Rama IV Road in Pathumwan district will be closed for 30-45 days for repairs after its steel structure was damaged by a fierce fire among some garbage bins stored underneath it on Tuesday morning.
Thiti Songcharoenkij, director of the Bangkok Metropolitan Administration's Construction and Maintenance Office, said a preliminary examination found the steel beams on the outbound lanes (heading to Klong Toey) were bent after being scorched by the fire for an extended period, causing the traffic surface to subside.
The inbound lanes sustained less damage, he said.
Mr Thiti expected the bridge would have to be closed for at least one month for structural repairs.
Jakraphan Phiewngam, a Bangkok deputy governor, said the repairs would take about 45 days. The bridge would be completely closed to traffic from today for safety reasons.
The BMA, metropolitan police and other related agencies would hold a meeting on Tuesday afternoon to discuss the matter, he said.
Pol Lt Gen Sanit Manathaworn, the Metropolitan Police chief, who in the morning examined the damage, said that engineers had advised that the bridge be closed for repairs for 45 days for the replacement of the steel beams bent by the heat.
The city's traffic would certainly be affected by the closure of four traffic lanes. Traffic police would adjust the traffic lights at the Witthayu-Sathorn intersection, starting Tuesday afternoon, he said.
He added the fire might have been caused by some reckless people who threw a burning cigarette into the spot where the garbage bins were stored under the flyover.
Footage of closed-circuit cameras in the area would be examined to find the cause of the fire, he said.
Her Royal Highness Princess Maha Chakri Sirindhorn presided over the official opening of the Thai-Belgian bridge on April 25, 1988.
The BMA and the Belgian Ministry of Public Works on Aug 19, 1986 agreed in a cooperation pact to build a flyover to ease traffic at the Sathorn-Witthayu and Rama IV intersection, known to be one of the most congested crossroads in Bangkok.
Belgium provided the bridge elements, the preliminary design and general supervisionof the construction work. The BMA did the foundation works, relocation costs and all other expenses related to the construction and use of the bridge.
Over 2,000 tonnes of steel and parts of a flyover in Brussels were then shipped from Antwerp to Bangkok for the construction. Once all the parts had arrived, it took just over a month to implement all ground and foundation work, three weeks to construct the lanes and 60 hours to assemble the 290-metre flyover.
Traffic is closed in the Thai-Belgian Bridge on Tuesday after a fire. (Photo by Apichart Jinakul)