Constructability Considerations in Selection and Design of Drilled Shaft Foundations for Bridges

Abstract

The great strength and ductility of drilled shaft foundations can be used to advantage on bridge projects in circumstances that favor their construction. However, drilled shaft construction methods contain risks of construction difficulties that must be addressed in the selection and design of drilled shafts. Some aspects of design and specification of drilled shaft foundations that can lead to constructability problems are described, and practical solutions that may satisfy the structural design requirements and lead to improved economy and reliability are offered. Many constructability problems relate to concrete specifications, congested reinforcement, splices, and construction of the column–shaft connection. The extent of the potential issues and the range of effective solutions often are dictated by the construction methods needed to accommodate the specific ground conditions at the site.