Seismic performance of pile-wharf connections

Imports and exports are essential to our economy, but the wharf structures that accommodate this activity are susceptible to earthquake damage. Wharves are pile supported structures, and the pile-wharf connection is an essential element of their seismic performance. Either precast prestressed concrete piles with moment-resisting connections or steel batter piles are used to provide lateral resistance, but precast concrete piles are more common. Little research has been performed on the seismic performance of these precast concrete pile-wharf connections. Eight experiments evaluating the seismic performance of moment-resisting precast concrete pile-wharf connections are described. The test specimens simulate the wide range of practice presently noted in wharf design. These connections tolerate large cyclic inelastic deformations, but they also show significant deterioration in resistance and stiffness. Extended pile connections are used when the pile is driven below deck level. Precast concrete pile connections are stronger than extended pile sections, but they degrade more quickly. Axial load on the pile also increases connection moment capacity but results in greater deterioration in resistance. Analysis shows that this degradation in resistance significantly reduces the inelastic pushover resistance and increases the inelastic dynamic response demands of the system.