LOAD-CARRYING CAPACITY OF STEEL RAILWAY BRIDGES SUBJECTED TO LONG TERM SERVICE ACCORDING TO EUROCODE STANDARDS

The paper presents a method of evaluation of static load-carrying capacity of steel structure railway bridges that are in service for longer than acceptable by Eurocode standards period of time. The procedure of application of railway bridges moving loads and requirements for analysis according to PN-EN 1991-2:2007 standard are presented in details. The old steel railway bridge under analysis was built in the late XIX century and used for over 100 years. Samples of the bridge steel material were examined in laboratory to determine the material real strength parameters taking into account a long term degradation process. The applied verification process revealed that the load-carrying capacity of main bridge girders could have been exceeded. Structures of similar age and lifetime are still used on railroad routes in our country. Results of the analysis show that requirements of actual standards may not be fulfilled which makes usage of these structures dangerous.