Safety, serviceability and durability are the basic parameters to ensure the reliability of the traffic infrastructure or its parts. The durability is the important parameter for design or evaluation of bridge construction. The durability is influenced by degradation processes as corrosion of reinforcing and structural steel during bridge lifetime or variation of mechanical properties of concrete due to environmental loads. The presented degradation processes and change of concrete mechanical properties during bridge lifetime markedly influence the resistance of cross-sections and elements deformation parameters. The project is focused on study of corrosion characteristics of reinforced concrete and steel bridge constructions as well as influence of environmental loads on change of concrete elasticity modulus. The corrosion map of Slovakia will by developed based on the aggressivity of environment supported by the in situ measurements on specimens in real environmental conditions and laboratory measurements.