Jacketing/ Micro Concreting

Strengthening and rehabilitation by reinforced concrete jacketing of columns is assessed, considering different practical aspects: anchoring and slab crossing of the added longitudinal reinforcement, interface surface preparation, spacing of added stirrups, and temporary shoring of the structure and addition of new concrete.

Structural rehabilitation represents an important aspect of the construction industry and its significance is increasing. Several methods are available, each with different advantages and handicaps. However, little information is available and insufficient code guidelines are accessible. In fact, most repair and strengthening designs are based on the assessment of engineers only and, often, empirical knowledge and current practice have an important role in the decisions to be made. One of the most commonly used retrofitting techniques: jacketing of reinforced concrete columns.

This method is evaluated according to different characteristics and, in order to help structural engineers to choose the most appropriate solutions, recommendations are given, based on published experimental research and real case studies. When, why and how to rehabilitate a structure WHEN the need to rehabilitate a structure may arise at any time from the beginning of the construction phase until the end of the service life. During the construction phase, it may occur because of design errors;

deficient concrete production; bad execution processes. During the service life, it may arise on account of: an earthquake; an accident, such as collisions, fire, explosions; situations involving changes in the structure functionality; the development of more demanding code requirements. WHY the decision to rehabilitate must be made only after the inspection of the structure, its structural evaluation and a cost/benefit study of the different solutions. HOW the choice of the repair and/or strengthening methods depends on the structural behaviour objectives. The goals of the strengthening strategies may be divided into increasing the resistance to lateral loads, improving the ductility, and an association of both.