Have Batter Piles Gotten a Bad Rap in Seismic Zones? (Or Everything You Wanted to Know About Batter Piles But Were Afraid to Ask)

Under most circumstances, plumb pile systems are more economical and are usually the system of choice for piers and wharves subject to seismic loading. However, there are situations where batter piles are desirable, such as under high service-level lateral loading conditions or where the new structure has to be compatible with an existing batter pile structure. For these situations, using displacement design with carefully-detailed batter piles may result in a significant project savings compared to a force-based seismic design method. This paper reviews the basic concepts of displacement design. Insight is offered on the behavior of batter piles using a simplified displacement method to show why batter pile structures are vulnerable to seismic loading if designed using a force-based method. Sample details and a design procedure for a proposed system are presented.