Next time you drive underneath a highway bridge, look up and you might see several small PVC pipes extending below the edge of the bridge. These may appear haphazard, but are actually a carefully designed drainage outlet for the structural bridge deck’s waterproofing membrane. These systems speak to the unique waterproofing challenges posed on bridges.
In a recent Civil + Structural Engineer article, “Membrane-Level Drainage on Highway Bridge Decks,” we explored some of these challenges, including the lack of consensus in the industry on how best to provide drainage outlets and improve pavement durability on bridge decks. There is a great opportunity for improved knowledge sharing and consistency across the country regarding bridge deck drainage to improve pavement durability, waterproofing longevity, and traffic safety.