A probe by the Safety Investigation Authority of Finland (Otkes) revealed that the Espoo footbridge that injured more than 20 people when it collapsed last May was dangerous and structurally inadequate.
Otkes issued a final report about the accident on Wednesday.
Twenty-two school-age children and one adult were injured in the accident. According to the report, six of the victims were left with permanent injuries.
"Even though no one was killed, there were serious injuries and some will have permanent damage. It's sad," Kai Valonen, chief investigator, told Yle.
According to Valonen, the investigation offered many teachable lessons.
The Otkes report noted that the footbridge's construction — made with scaffolding equipment — had not been properly planned out by anyone, and no relevant authority had looked over the plans that were drawn up.
According to the report, changes were made to the bridge's design as it was being assembled, but the possible safety implications of the changes were not examined.
"The construction of the Tapiola scaffolding bridge was not recognised as building a bridge, and as a result, it was not subject to any standardised processes, such as safety requirements or technical supervision," Valonen said in a press release.
No safety deficiencies were found during the design, assembly or commissioning of the bridge, nor during the weekly inspections while the bridge was in use.
Otkes did not comment about which authority should have been in charge of the structural design, the City of Espoo or the scaffolding supplier.
"In this case, the supplier did not draw up the proper schematics and the client did not realise that they were required, even though the structure was critical," Valonen said.
The report also found that while the project manager in charge of the collapsed bridge had been working in the scaffolding industry since 2011, this person lacked engineering qualifications. The project manager had graduated from high school and had attended one course on building statics and material strength offered by their employer.
As Otkes issued its final investigation report, the police are also conducting a separate investigation into the accident.
Edited on 1 March to add detail about the project manager.
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