Saint Sebastian Bridge: Reuse Requires Creative Thinking

The Sint Sebastiaansbrug (Saint Sebas­tian Bridge) in Delft, the Netherlands, was built in 1964. The bridge crosses the Delftse Schie, or waterway, with a fixed span of 12 m (39 ft} and a movable span of 12 m (39 ft). In the middle of the waterway, both the fixed and movable bridge decks rest on a pier. The vertical clearance of the fixed part is 4.5 m (15 ft}. On both banks there is an ap­proximately 80 m (262 ft) long access ramp, consisting of a concrete con­struction on piles. Each section of the access ramp has a span between supporting structures of approximately 10 m(33 ft}. During the preparations for con­verting the bridge to accommodate a tram in 2006, a thorough inspection of the bridge was executed. The inspection conclusions were very unfavourable. Several supporting structures had settled considerably, causing structural damage to the upper structure. Adding bearing capacity to the failed foundation, repairing the struc­tural damage and accommodating the tram on a wider bridge was studied in 2010 and was found unfeasible and the uncertainty profile associated with this solution was also considered to be too high.