Finland's Safety Investigation Authority (Otkes) has identified numerous deficiencies in the design and construction of the temporary footbridge that collapsed in Espoo's Tapiola district last month.
The agency said on Tuesday that many parts of the collapsed pedestrian bridge were too weak for their intended purpose.
The weakest parts of the structure, according to Otkes, were the attachment components at the ends of the transverse beams. These parts opened up, causing the transverse beams, platform levels, and plywood sheets to collapse. Another factor contributing to the damage was the fact that the attachment components were not bolted down, according to Otkes.
The preliminary investigation also found that the 7.7-meter longitudinal beams were weak.
The bridge collapse in mid-May led to the hospitalisation of about 24 people, the majority of whom were eighth graders on a school trip.
Would you like a roundup of the week's top stories in your inbox every Thursday? Then sign up to receive our weekly email.