Flexural retrofitting of reinforced concrete bridge pier type cross-sections with carbon fiber reinforcing plastics

摘要

Results and conclusions are presented from an experimental investigation with identical column-specimens, which were constructed with prototype materials, having a height of 1600mm and a cross section 300mm by 200mm. They represent models of a part of a bridge-pier near its base, with or without partial confinement of Carbon Fibre Reinforcing Plastic (CFRP) layers. They were subjected to compressive loads as this type of stress field is expected to develop at the base of such vertical members under combined vertical loads and seismic actions, where undesired compression failure may develop. The retrofitting of this type of reinforced concrete cross sections, with h/b ratio larger than 1.5, is aimed at prohibiting, up to a point, such compression failure. This type of partial confinement may also be applied to retrofitting similar vertical structural members with non-accessible sides. With the successful application of this partial confinement, an increase of almost 50% was observed in the compression capacity of the test specimens. Moreover, the deformability of these specimens was substantially increased, demonstrating the effectiveness of this type of partial confinement. It was also demonstrated from the experimental sequence that critical factors for the effectiveness of this partial CFRP confinement were the type of anchorage of the CFRP layers on the body of the cross-section and the number of CFRP layers.