The Isabela bridge collapse is being investigated by authorities, with structural stability and overloading identified as possible causes of the incident.
According to the Department of Public Works and Highways (DPWH), the Cabagan-Sta. Maria Bridge was supported by a solid steel beam instead of cable strands.
DPWH Secretary Manuel Bonoan explained that this design is unusual, as cable strands are typically used for such structures due to their tensile stress capability.
In addition to the design concerns, authorities are also looking into overloading as a contributing factor to the collapse.
Bonoan stated that the bridge was overstressed, prompting the agency to consider filing charges against the truck company involved.
The bridge collapsed on February 27 after a dump truck crossed it, injuring six people.
According to the DPWH, the bridge was designed to accommodate up to 44 tons, far below the estimated 100-ton weight of the truck.
The bridge had initially remained closed to the public due to design modifications.
It underwent retrofitting in 2022 to comply with the DPWH’s updated design code.
The retrofitting was completed in 2024, and the bridge was reopened on February 1 this year, but only for limited and lightweight vehicles.
