Bridge 11, Vertical-lift bridge in Allanburg, Thorold, Canada

Bridge 11, also called the Allanburg Bridge, is a through-truss vertical-lift bridge carrying Highway 20 over the Welland Canal in Thorold, Ontario. Its main span measures 60.9 metres, and the lift span gives ships 36.5 metres of clearance. It was designed by Harrington, Howard & Ash, the predecessor of HNTB.

The site hosted the groundbreaking ceremony for the Welland Canal before the bridge itself was built and completed in 1930. It was designed by Harrington, Howard & Ash, the predecessor of HNTB. On August 11, 2001, the lift span was lowered before the MS Windoc had cleared the structure; the ship was struck and caught fire. After minor repairs, the bridge reopened to vehicular traffic on November 16, 2001.

The bridge carries Highway 20, the road link between Niagara Falls and Fonthill, so local traffic and canal shipping share the same crossing point at Allanburg. The site itself is where the groundbreaking ceremony for the Welland Canal took place, tying the bridge to the waterway's founding. The 2001 collision with MS Windoc, when the lift span came down before the ship had cleared, is still the event most associated with the structure.

The lift span rises for ships, so road traffic on Hwy 20 between Niagara Falls and Fonthill stops during each passage; plan around vessel movements rather than rush hours. The deck sits 36.5 m above the water when raised, and the 60.9 m main span is visible from the canal banks in Allanburg, Thorold.

The bridge's lift span was lowered onto the MS Windoc on August 11, 2001, before the ship had cleared; the freighter caught fire and the bridge reopened to vehicles on November 16, 2001 after minor repairs. The span was designed by Harrington, Howard & Ash, predecessor of HNTB.