A 20m-tall tree was toppled during a thunderstorm on Thursday night, damaging a pedestrian overhead bridge near Bishan Street 12, behind Guangyang Secondary School.

The fallen tree crushed the railings and shelter along a section of the bridge. The area's residents said the incident happened around 10pm. Nobody was hurt.

The overhead bridge, which spans Braddell Road, links Bishan and Toa Payoh towns and is used by many residents.

The Land Transport Authority (LTA) said yesterday that the ramp leading to the bridge is now temporarily closed due to the damage, but pedestrians can continue to use the bridge via the stairs, which are not affected.

Meanwhile, it will put in temporary railings and shelter while repairs proceed. The full repair works are expected to take several weeks, the LTA said. The fallen tree, of the species commonly known as Senegal mahogany, is managed by the Bishan-Toa Payoh Town Council. It is suspected to have fallen due to the recent downpour, the town council said, adding that it was notified of the incident at 4am yesterday.

The town council is currently working with the LTA to repair the bridge, but declined to reveal how much it would cost.

Contractors who were removing the tree from the site had to saw it into about 10 pieces before transporting it away in two lorry loads.

Bishan resident Magdalene Leow, 54, who works in the printing industry, said she heard a "loud bang" on Thursday night, almost like the sound of a car accident.

"I didn't expect it to be a tree falling. It's very fortunate that nobody was on the bridge at that point in time. We use it all the time to go to the bus stop ," she said.