BEHAVIOUR OF PARTIALLY STRENGTHENED REINFORCED CONCRETE COLUMNS UNDER AXIAL LOADS

Abstract

The column is the most important structural element in the structure . It has usually the main responsibility of the building distortion . In this respect , the repair and strengthening of columns if it is necessary is a very important subject to reduce the building failure . Repair and strengthening of columns by using concrete jackets is a common method from very long time . Many researches had been done to study the global behaviour of the original columns and strengthened columns. Most of previous researches focused on the full length strengthened or complete repair of the column, even there is a local defect in this column. Non of the previous research work studied the local strengthening of the defected part in the column . In this research the partial strengthened columns to repair the defected part only is investigated experimentally . The construction deficiencies such as the bad quality of concrete and the bad arrangement of horizontal reinforcement (stirrups) are only investigated. This study takes into consideration four basic parameters . These parameters are as follows : - (a) Type of defect. (b) Location of defect . (c) Jacket height . (d) Type of strengthening . The Summary of the research chapters is as follows :- Chapter one includes historical background , the main causes of defects , different shape of building defects , determination of the defected part and its propagation , and the summary of this research . Chapter two explains the objectives of repair and strengthening , the basic steps of concrete repair works , and the repair materials . The chapter includes also , a brief discussion of the different techniques of repair and strengthening