Abstract
Rocking response of a direct foundation under a strong near-field ground motion may result in the uplift in the foundation, and it often results in the yield of the underlying soils. The rocking response with uplift interacts the nonlinear hysteretic response of a bridge that is supported by the foundation. This paper presents how large uplift is expected in a direct foundation that is designed in accordance with the traditional elastic static seismic method, and the effect of rocking response on the hysteretic response of a bridge pier. It is found that the rocking response result in about 0.1-0.2m uplift in a direct footing, with 6.5m long and 7m wide, that supports a 10m high standard viaduct. It is also found that the rocking response of a direct foundation reduces the nonlinear hysteretic response of a bridge pier.
