Thames Barrier

The Thames Barrier is one of the largest and most prestigious moveable flood defence structures in the world. Rendel (formerly Rendel Palmer & Tritton) designed and supervised the construction of this major project.

The structure covers the entire width of the River Thames at Woolwich with four main openings of 61m to permit navigation and six subsidiary gated openings. A novel feature of the project is the use of 19m high, 3,300 tonne rising sector gates in the navigational openings, which lie in recessed sills in the river bed when not in use and normally allow unobstructed passage of river traffic through the barrier. Each gate is pivoted and supported between concrete piers which contain operating machinery and control equipment. All gates are designed to withstand a differential head of 9.9m on the downstream side and 6.1m on the upstream side and are capable of resisting ship collision. When a flood threat is imminent, the gates are swung up through 90 degrees to a vertical position and form a continuous barrier across the river. Closure takes approximately 30 minutes.

Rendel has been involved with the Thames Barrier since its inception and has been involved in the following aspects of its lifespan:

• Extension of life of barrier (originally 50 years but in 2009 increased to 120 years) combatting the dangers of climate change, potential increasing sea levels and the higher probability of tidal surges on London
• Extensive hydrological and tidal investigations, hydraulic and model studies
• Engineering design (including design of gates and operating machinery)

Rendel has provided detailed services including provision of advice with regards to analytical and physical investigation and preparation of focus documents provided to simplify and clarify the intended function of the barrier gates.

Further studies have included detailed finite element analysis of the structure to confirm areas of high stress concentrations using advanced computing techniques which were not available at the time the original design was carried out.