The eastern half of the San Francisco-Oakland Bay Bridge between Yerba Buena Island and Oakland California is being replaced for seismic reasons. The Skyway portion of this bridge consists of parallel precast, prestressed concrete box girder structures constructed by the balanced cantilever method.

Each of the parallel bridges is approximately 2100 meters long and over 25 meters wide. Each parallel bridge is comprised of fifteen spans that vary between 64 and 160 meters in length. The superstructure is a haunched single cell box girder constructed of precast segments. Besides normal highway traffic, the bridge is designed to carry light rail vehicles.

The expansion joints between frames incorporate a unique design consisting of large diameter steel bearing pipes designed to transfer both vertical and horizontal forces. The pipes are machined to a near perfect circle and clad with stainless steel. The pipe slides along the axis of the bridge on Teflon coated elastomeric pads.

A steel box girder span with an orthotropic deck is provides as a transition between the skyway and the signature span consisting of a two span self anchored suspension structure.

Piers for the skyway structure are made up of four octagon shaped columns that are tied together with full height connecting walls. Pier lengths are tuned to minimize temperature and prestress shortening forces and maximize seismic resistance. The superstructure-pier connections are designed to assure that no damage occurs to these joints during an earthquake.

The base of each pier is cast into a large socket provided in the unique concrete filled steel pile caps. The caps are supported by 2.5-meter diameter concrete filled steel pipe piles driven on a batter. Piles are driven though sockets in the caps and connected using a combination of field welded steel plates and high strength grout to develop full axial and bending capacity of the piles. Piles extend nearly 100 meters into dense gravels in order to resist the large seismic loadings.

NRV Principal, Charles Redfield, played a key role in developing the preliminary design concept for this bridge as well as the main span alternatives. NRV was also a major part of the design team. Mr. Redfield was instrumental in final design of the superstructure and the expansion joints described above, while Mr. Nutt developed design criteria and had a key role in design of the foundations including the unique steel pile caps, the pier-to-pile cap connections, the pile-to-pile cap connections and the pile foundations. Both Mr. Redfield and Mr. Nutt were part of the on-site construction support team that provided a designer liaison with the contractor and owner including the successful resolution of several field problems.