New bridge construction with hybrid systems

4 Footbridge erected in the Khimki, Moscow region, image courtesy of ApATeCh Co. Ltd., Moscow, Russia. 

Hybrid systems may be elassified as (1) struetural eomposite produets with hybrid hbres or (2) stmetural systems eonsisting of hybrid eomposites and eonventional materials. The first category involves a product-level definition that is made by the combination of hbres and polymers to form unidirectional structural elements such as composite plates, rods, tendons and strands. The second category involves a system level that is dehned by incorporating FRP composite components into a stmctnral member made from the more traditional materials. 

Some examples of hybrid structures are discussed in the following sections. 

Hybrid FRP/concrete stmetural columns filled with concrete with or without internal reinforcement have been investigated by many researchers including Fam and Rizkalla (2001a) Mirmiran (2003) and Xiao (2004). This work was extended to two concentric FRP tubes where the annulus was filled with 

In practiee the FRP eolumns have largely superseded the eonerete-filled steel jackets. The former hybrid systems have many advantages over steel-jacketed systems  

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