Refurbishing the N-II highway bridge in Sant Adrià de Besòs, Barcelona

Measuring 145 metres, the N-II highway bridge’s deck sits on 5 tapered, double-T site-cast concrete beams. There were two building stages: the first was a three-beam, 15 metre-wide bridge built according to a 1941 project; the second saw the bridge widened by 10 metres in 1962. In terms of structure, the deck is made of two reinforced concrete frames, one on each side of the river, measuring 60 m long with a 25 m bi-supported central span. Each frame sits on two piles and one abutment. 

When reviewing the bridge several problems were found. Due to the increase in volume of the rusted rebar, some of the concrete cover was lost, leaving reinforcement exposed. 

Other sections showed signs of moisture with blooms present on slabs. A refurbishment plan was drawn up to repair these defects, which included: 

• Pressure washing all surfaces to roughen and aerate for increasing product bonding. 
• Applying corrosion inhibitor to stop the process’s electrolytic current. 
• Passivation of reinforcement and rebuilding bridge fitting using R4 mortar. 
• Carbon fibre sheet reinforcement of pile foundations and main beams adjacent to pile rows where the amount of reinforcement lost is above the specified threshold. 
• Coat of anti-carbonation paint on all surfaces.