SOME PARAMETERS AFFECTING THE STATIC BEHAVIOR OF NORMAL AND HIGH STRENGTH CIRCULAR R.C. SHORT COLUMNS CONFINED BY CFRP

Abstract

Concrete columns have an important function in the structural concept of many structures. Often, these columns are vulnerable to exceptional loads (such as impact, explosion or seismic loads) , load increase ( increasing use or change of function of structures, etc.) and degradation ( corrosion of steel reinforcement, alkali silica reaction , etc.). On the other hand, confinement of concrete is an efficient technique to enhance the structural behavior of concrete members primarily subjected to compression .Structural repair and rehabilitation of reinforced concrete structures is becoming an increasing important option for all deteriorated / damaged structures to restore, enhance the load bearing capacity and increase the life span of the structure. The strengthening of concrete structures with externally bonded reinforcement is generally done using either steel plates or FRP laminates. The main disadvantages of using steel plates are steel corrosion in the adhesion zone, heavy weight and excessive size of single plates. With the development of technology , the use of high- strength concrete members has proved most popular in terms of economy, superior strength , stiffness, and durability. With the increase of concrete strength, the ultimate strength of the columns increases, but a relatively more brittle failure occurs. The lack of ductility of high strength concrete results in sudden failure without warning, which is a serious drawback. [1] .The application of FRP in the construction industry can eliminate some unwanted properties of high strength concrete , such as its brittle behavior [2,3]. To study the behavior of normal and high strength circular R.C.columns confined with CFRP under statically load, tests on columns wrapped with FRP have been executed. The efficiency of externally bonded CFRP of circular R.C.columnsis declared and evaluated.