Monitoring of Thompson's bridge BFRP reinforced deck with discrete optical sensors

Over the past 20 years many concrete bridges have exhibited problems associated with reinforcement corrosion and their repair can cause disruption to traffic and the associated costs of congestion are high. A further problem for bridge deck slabs is the need carry heavier lorries under increased European loadings. This paper describes the replacement of corrodible steel rebar with corrosion resistant basalt fibre reinforced polymer (BFRP) rebars in a bridge deck slab and monitoring of their performance in comparison to steel rebar using discrete optical sensors and other SHM techniques. Thompsons bridge in Northern Ireland, is beam and slab bridge and the deck was cast with self-consolidating concrete (SCC) to further improve the durability and lower the carbon footprint. The SHM regime assisted in the acceptance of these new materials and in mitigating the risk by demonstrating excellent structural performance. It was concluded that the BFRP reinforced concrete bridge deck slab exhibited similar behaviour to the equivalent steel reinforced bridge deck slab. The maximum test load was nearly three times the current maximum European wheel load. The strain values were very low and 8.5 times less than the rupture strain of the BFRP bars at an applied load of 40t which is far in excess of the current EU wheel load of 15t. The BFRP rebar provided an alternative corrosion resistant system which can substantially improved whole life performance compared to corrosive steel rebar.