Grenfell's quite different to this. More similar is the Hammersmith Flyover where they recently had an issue with a post tensioned 60s structure, and corroded tendons snapping. In that case drastic action was taken, closing the structure (even though it carried arterial roads) and instigating a programme to replace the tendons gradually.
A common issue with many of the 1960s reinforced concrete structures is the difficulty of inspecting key structural members (e.g. encased tendons which may have also been the case with the Genoese bridge), lower standards than current (so the distance to reinforcement is less and corrosion is more likely) and maintenance regimes with lowered funding to repair an increasing number of deficient structures.
A common issue with many of the 1960s reinforced concrete structures is the difficulty of inspecting key structural members (e.g. encased tendons which may have also been the case with the Genoese bridge), lower standards than current (so the distance to reinforcement is less and corrosion is more likely) and maintenance regimes with lowered funding to repair an increasing number of deficient structures.