University of Canterbury. Civil and Natural Resources Engineering
Abstract
A major lesson from the 2011 Christchurch earthquake was the apparent
lack of ductility of some lightly reinforced concrete (RC) wall structures. In particular,
the structural behaviour of the critical wall in the Gallery Apartments building
demonstrated that the inelastic deformation capacity of a structure, as well as potentially
brittle failure of the reinforcement, is dependent on the level of bond deterioration
between reinforcement and surrounding concrete that occurs under seismic loading. This
paper presents the findings of an experimental study on bond behaviour between
deformed reinforcing bars and the surrounding concrete. Bond strength and relative bond
slip was evaluated using 75 pull-out tests under monotonic and cyclic loading. Variations
of the experiments include the loading rate, loading history, concrete strength (25 to 70
MPa), concrete age, cover thickness, bar diameter (16 and 20 mm), embedded length, and
the position of the embedded bond region within the specimen (deep within or close to
free surface). Select test results are presented with inferred implications for RC structures