Rust, inspection failings and ‘improper construction’ possible causes of Taiwan bridge collapse

The 140m-long single arch bridge suffered a catastrophic collapse in October last year, crushing fishing boats below and killing six people. Dozens more were injured.

The bridge – although only 20 years old – had previously undergone remediation work after a 2016 report found that the expansion joints were "obviously warped, damaged and sagging".

Shortly after the collapse, investigators from the Taiwan Transportation Safety Board (TTSB) revealed that they had found corrosion in several of the suspension bridge’s steel cables.

This week the TSSB announced its initial findings including “deficiencies in several of the bridge's suspenders, including rust damage and steel strands which had escaped from their anchors on the bridge's arches and deck”.

The TSSB also said that there were questions over the inspection regime of the bridge, with no inspections taking place since 2016. Yilan County inspected the bridge a total of seven times from 2001-2016. In April 2016, responsibility for the bridge was transferred to the region’s Maritime & Port Bureau, and no further inspections were conducted, the TSSB said.

The TSSB also said that there are concerns about “improper construction” carried out on the bridge in the years leading up to the collapse, as well as heavy loads carried across the crossing.

Between 2005 and 2019 the bridge underwent 60 road construction projects, which nearly doubled the thickness of some portions of the road to 175mm.

Meanwhile, from October 2016 to September 2019, the port authorities transported concrete loads across the bridge four times for use in the construction of a coastal seawall.

The Taiwan International Ports Corporation is conducting an internal review of its maintenance regimes following the collapse.

A final report by the TSSB is expected in August.

Like what you've read? To receive New Civil Engineer's daily and weekly newsletters click here.