Author(s)

S. Dritsos

Abstract

As knowledge increases and buildings in seismic regions are designed with higher degrees of safety, it becomes clear that older structures may require upgrading. In general, codes or regulations to aid the engineer in this field do not exist. At the present moment in Greece and with regard to reinforced concrete structures, there is a considerable effort being placed into making up this shortfall. As part of this effort, this paper concentrates on the latest design procedures for strengthened reinforced concrete composite elements. Modern seismic design of existing structures is moving towards a displacement capacity assessment of the structure. For monolithic elements, curves and formulas exist to evaluate the values for the yield strength and for the displacements at both the yield stage and at the failure stage. No information exists for the corresponding values for a strengthened element. By applying suitable corrective factors to a monolithic element the capacity curve of a strengthened element can be converted to the corresponding field of monolithic design. This paper defines the required correction factors and presents experimental results from different strengthening methods used to construct concrete jackets. The experimental results are then used to propose preliminary design values for the required correction factors. Equations for use with the correction factors are also described. Finally, the correction factors are compared with those provided in the relevant codes. Although based on a limited database of experimental results, it has been found that the monolithic behaviour coefficients do not always correspond to the relevant values proposed in design codes. Keywords: repair, strengthening, retrofitting, design, reinforced concrete, jacket and column.

Keywords

repair, strengthening, retrofitting, design, reinforced concrete, jacket and column.