Reinforcement of engineering structures using composite materials

A study of the pathological behavior of reinforced concrete, prestressed concrete, steel and timber structures reveals material and structural damage caused by design errors, changes in operating conditions and material ageing. A survey carried out by Setra (Service d'études techniques des routes et autoroutes) in 1995 [1] shows (figure 1 ) that 16% of structures present disorders requiring repair work, while 37% require urgent specialized maintenance. It should be remembered that the lifespan of a structure is around 100 years. According to L. Le Métayer, in a survey carried out by Bureau Veritas, 35% of claims occur between 4 and 10 years after the structures were commissioned.

The cost of monitoring and rehabilitation represents more than 45 billion euros (300 billion francs) per year [2] . Depending on the different causes of disruption, maintenance operations consist of :

• protect them by limiting corrosion and ensuring better sealing conditions;

• repair them to compensate for any loss of rigidity or strength;

• reinforce them by improving the structure's performance and durability.

Thanks to their high mechanical properties and low deadweight, their excellent corrosion resistance and their forming and molding capabilities, composite materials are particularly well suited to the reinforcement of civil engineering structures.