Composite rehabilitation systems rehabilitate concrete structures

Composite rehabilitation systems (CRS), i.e., structural hybrid systems involving advanced polymer composite (APC) materials (generally referred to as fibre-reinforced polymer, FRP), structural adhesives (SA) and conventional construction materials (CCM) (e.g., timber, concrete, masomy, steel, iron), constitute one such technology. 

The materials, systems/applications and design/regulations presented in the following sub-sections are concerned primarily with the rehabilitation of timber and concrete structures. In spite of this, a brief section is also added to very succinctly discuss the use of composite rehabilitation systems in metallic and masonry structures. 

Structural rehabilitation of timber and concrete structures with composite systems can be generally accomplished in one of two ways (Karbhari and Seible, 2000) using wet lay-up or cured in-situ systems, by application of composite overlays, fabrics, sheets or fibre tows (Fig. 22.4) and using systems involving the bond of prefabricated APC materials, such as straight pultruded strips, and factory-made curved or shaped elements (Fig. 22.5). 

The main applications of composite rehabilitation systems in the rehabilitation of timber structures are described in Table 22.1 and Fig. 22.6, and of concrete structures in Table 22.2 and Fig. 22.7. 

As already evidenced in the above text, currently and at a European level, no well-established design and detailing calculation methods embracing all techniques have been developed for the on-site use of composite rehabilitation systems in timber and concrete structures. Nevertheless, the development of suitable design guidance standards is far more advanced in the case of the rehabilitation of concrete structures than of timber stmctnres. Therefore, for most applications the designers of timber structures composite rehabilitation... 

Abstract This chapter continues the discussions of the development of advanced polymer composite material applications associated with bridge engineering. It focuses on the rehabilitation of metallic bridge structures, all-FRP composite bridges and bridges built with hybrid systems. Chapter 16 covered the materials used in FRP composites, in-service properties and applications of FRP composites in bridge enclosures, the rehabilitation of reinforced and prestressed concrete bridge beams and columns. 

As discussed in the previous chapter, advanced FRP composites have a key role to play in the repair and construction of bridge stmctures. They have been used in the rehabilitation of both ageing concrete and metallic bridge structures. The unique in-service and mechanical properties, viz. durability, high specific stiffness and strength, etc., of advanced FRP composites for the civil infrastructure suggest their suitability for integration in hybrid structural systems as well as the development of all advanced FRP composite structures. 

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