The durability of the structure is the ability to maintain its stability, function and aesthetics due to environmental effect, without significant damage and major maintenance costs. When considering durability, it is important to know the mechanisms for the entry of external causes of damage into the concrete, which are: permeability, diffusion and sorption. The entry of harmful substances into the concrete leads to corrosion, which is the biggest problem of the durability of reinforced concrete structures. The corrosion can be divided into concrete corrosion and steel corrosion. The most common causes of concrete corrosion are various chemical actions and mechanisms such as freezing and fire. The corrosion of the reinforcement can be divided into two periods, the initiation period characterized by carbonation and penetration of chloride, and the propagation period. In this work it will be presented methods of testing durability parameters such as: water permeability, gas permeability, resistance to cyclic freezing and thawing, chloride penetration and abrasion resistance. Durability can be designed in two ways, according to norms or according to its usability properties. The first problems of the Krk bridge appeared shortly after its launch. Regular inspections of the bridge structure showed the major problem with corrosion caused by the high chloride content in concrete. In the meantime, a system of protection was found to significantly reduce the penetration of chloride into the bridge structure which provided longer structural life.