SHEAR STRENGTH OF REINFORCED CONCRETE COLUMNS UNDER CYCLIC LOAD REVERSAL

摘要

1995 Hyogo-Ken Nambu earthquake brought severe damage to many RC bridge piers. Especially, it is observed that shear failures led several RC bridge piers to total collapse. From the experience of this earthquake, "Japanese Design Specification for Highway Road Bridges" was revised in October 1996 adopting several new concepts on seismic design including the new practical design method on shear capacity of RC piers during large earthquakes, of which two major revisions are consideration of size-effect and of effect of cyclic load reversals. This paper shows the result of cyclic load reversal tests of 6 RC column specimens carried out to evaluate the shear strength reduction of concrete. It is shown that the shear strength of concrete subjected to cyclic load becomes smaller compared to one subjected to monotomic load, and reduction rate is affected by the number of loading reversals.