Reinforced concrete is an extremely popular construction material. It becomes versatile with its both compressive and tensile properties. Concrete is naturally strong in compression but its tensile and bending strength is small fraction of compressive strength. This limitation is overcome by introduction of reinforcing steel bars and in case of composite construction, structural steel sections.
Although hundreds of thousands of successful reinforced concrete and masonry buildings are annually constructed worldwide, there are large numbers of concrete and masonry structures that deteriorate, or become unsafe due to changes in loading, changes in use, or changes in configuration. Also from the recent earthquake of Gujarat it is clear that the old structures designed for gravity loads are not able to withstand seismic forces and caused wide spread damages. Repair of these structures with like materials is often difficult, expensive, hazardous and disruptive to the operations of the building. The removal and transportation of large amounts of concrete and masonry material causes concentrations of weight, dust, excessive noise, and requires long periods of time to gain strength before the building can be reopened for service.
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CARBON FIBER COLUMN WRAP |
On the other hand, Fiber Reinforced Composite (FRC) materials, originally developed for the aerospace industry, are being considered for application to the repair of buildings due to their low weight, ease of handling and rapid implementation.
The (FRCs) are unaffected by electro-mechanical deterioration and can resist corrosive effects of acids, alkalis, salts and similar aggregates under a wide range of temperatures. This novel technique of rehabilitation is very effective and fast for earthquake affected structures and retrofitting of structures against possible earthquakes. This technique has been successfully applied in the earthquake-affected Gujarat.
Appropriate configurations of fiber and polymer matrix are being developed to resist the complex and multi-directional stress fields present in building structural members. At the same time, the large volumes of material required for building repair and the low cost of the traditional building materials create a mandate for economy in the selection of FRP materials for building repair. Analytical procedures for reinforced and prestressed concrete and masonry reinforced with FRC materials need to be developed, validated, and implemented, through laboratory testing, computational analysis, full-scale prototyping, and monitoring existing installations.
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