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Deterioration of reinforced concrete structures may take place due to improper design or detailing inappropriate execution or erection, overstressing, or durability problem. Unless an efficient repair technique is carried out, full structural restoration is impossible. Jacketing , plate bonding and external fibe reinforced polymer (FRP) wrapping/filament are the most common repair/strengthening techniques that have emanated in the previous two decades. The implications of applying various repair systems to different structural members influence the anticipated modes of failure, damage evolution, strength and ductility.
Efforts devoted to repair, rehabilitation, and strengthening of reinforced concrete structures have been oriented into two main directions; wet and dry approaches. The use of plate bonding and fiber reinforced polymer (FRP) wrapping belongs to the latter. Both turned to be more appealing because of their advantages of application with minimal disrupt, adequacy for member size limitation and possibility of execution without interruption of structural performances. However, the conventional repair system by jacketing remained more economical in many applications. The overall preference of any of the techniques depends mainly, among other factors, on the following:
1.The structural system: framed system, chimney, water tank, bridge system, etc.
2.The structural member type: column, wall, beam or beam-column joint.
3.The type of loading: dynamic excitation, short-tem repeated loading, fatigue, impact or quasi-static monotonic loading.
4.The expected load combination: axial force with b ending moment of small or large eccentricity, pure bending, shear and torsion.
5.The durability aspects of each technique according to the exposure conditions to cycles of drying and wetting, high and low temperatures, or conditions of high shrinkage or high salt concentrations.
6.The structural integrity attained by each repair system with respect full or partial composite action.
In the absence of accurate, rigorous, yet simple, design procedure, the application of such a technique leads to hazardous failure mechanisms. The outputs of the proposed project will provide a systematic methodology that may be followed in related circumstances. In addition, training of a technical team in a professional manner will help sound implementation of the required repair technique. Exposure to the new aspects and methodologies in the rehabilitation field is a goal by itself for which specialized symposiums, conferences and workshops are annually held. |