An extensive probe of concrete road and railway bridges in Finland has only turned up one that did not meet durability standards.
The Finnish Transport Agency (FTA) says that even that one exception does not pose an immediate safety risk.
The agency launched the investigation after revelations of quality problems with some concrete structures. It inspected more than 90 of the most heavily-used road and rail bridges around the country. The bridges were built between 2005 and 2016.
"Only one site did not meet the sturdiness requirements, the Kuivajoentie underpass bridge on the Oulu-Kemi train line, which was built in 2016. It does not pose a safety risk, but we will carry out more a detailed study of the decline in its bearing capacity,” the FTA’s Head of Engineering Structures, Minna Torkkeli, said in a statement on Monday.
The agency says the Kuivajoentie bridge can now support a maximum axle load of 22.5 tonnes, whereas it was designed for an axle load of 35 tonnes.
Torkkeli says that the bridge's air content was incorrectly measured when it was built. It was now found to be 12 percent, whereas the maximum permissible content is around five percent.
More bridges to be tested and re-tested
The probe measured concrete soundness and air content. Excess air in concrete undermines its strength.
"Several bridges had elevated air content. However the strength margins were so large in the bridges with high air content that they meet the strength criteria, with the exception of this one bridge," says Torkkeli.
The FTA plans to still examine about 10 more bridges for quality assurance purposes. It will also revisit bridges found to have problems in the previous round of inspections in 2016. At that point the agency found shortcomings in six road bridges around the country.