Cable-stayed bridge 3-span cable-stayed bridge, the loads from the main spans are normally anchored back near the end abutments by stays in the end spans. For more spans, this is not the case and the bridge structure is less stiff overall. This can create difficulties in both the design of the deck and the pylons. Examples of multiple-span structures in which this is the case include Ting Kau Bridge, where additional 'cross-bracing' stays are used to stabilise the pylons; Millau Viaduct and Mezcala Bridge, where twin-legged towers are used; and General Rafael Urdaneta Bridge, where very stiff multi-legged frame towers were adopted.
Pontoon (boat) boat without much warning, particularly a top-heavy boat. Common boat designs are a catamaran with two hulls, or a trimaran with three hulls. Boats with three hulls are sometimes called "tri-toons." Small inflatable pontoon boats are one or two person, catamaran type boats, designed for leisure and fishing. Their pontoons are made out of abrasion resistant PVC and nylon with aluminum, steel and/or plastic frames for support. In today’s setting, more and more people prefer to use frameless pontoon boats. They are powered with paddles, oars and often with electric trolling motors using deep cycle lead batteries. Commonly they are