DUAL PURPOSE TUNNEL BECOMES A VERY SMART SOLUTION

Malaysias Stormwater Management and Road Tunnel (SMART) project in Kuala Lumpur features an innovative dual purpose tunnel. A 9.7-km-long water diversion tunnel is being constructed to alleviate continuous flooding problems that have left traditional mitigation measures overwhelmed. Situated above the flood tunnel is a two-deck 3-km-long highway that will run through the central third of the tunnel. For most of the time, the tunnel will be completely dry. During moderate storms, the upper two decks will still accommodate traffic, while the lowest gallery will serve as a stormwater tunnel. In more severe weather, the traffic flow will cease altogether, and water gates in shafts that seal the ends of the road will open for moving the flood water. Once clean-up efforts are completed, the road tunnel will re- open. The article describes the tunnels design and tunneling procedures, and discusses the need for novel features to accommodate the tunnels flood relief function. Unique project challenges, such as the unusual roadway structure, difficult ground conditions, and steep tunnel curvature are also described.