As the price tag climbs into the billions and commuters face re-routes and higher tolls, the Bay Bridge rebuild is crawling along, beset by cost overruns, largely because of the complicated and untested design of a short but visually striking stretch of the 4.5-mile crossing.
The 1930s-era Bay Bridge, which carries 280,000 vehicles daily and is one of the longest in the country, is composed of two spans. The western span links San Francisco with Yerba Buena Island; the eastern span links Yerba Buena Island with Oakland.
After the 1989 Loma Prieta earthquake shook loose a section of the eastern span, Caltrans — the state agency that oversees the bridge — accelerated plans to retrofit both spans for better protection against earthquakes.
The 1.8-mile western span retrofit was completed early last year at a cost $471 million — which was $82 million less than originally budgeted.
The eastern span, on the other hand, is being replaced — and the project is running a decade behind schedule and up to $4 billion over budget compared with 2001 estimates, according to the project’s latest financial update.
Construction of most of the eastern span was completed in 2007 as a 1.2-mile elevated skyway, which follows its predecessor’s basic style but uses technology that Caltrans says will better protect it during earthquakes.
But problems have arisen, largely because the skyway is being painstakingly linked with Yerba Buena Island through construction of the world’s longest self-anchored suspension bridge.
Unlike most of the world’s self-anchored suspension and conventional suspension bridges, which use two or more towers, the 2,050-foot self-anchored suspension section has a single tower that will stretch 525 feet into the sky. The tower will support cables that will form unusual triangular patterns.
The remarkable appearance helped clinch the ambitious decision to pursue the design, after elected officials squabbled in the 1990s and pushed for a postcard-worthy landmark.
But the design is coming at an ever-ballooning cost to toll-payers who use the Bay Bridge and six other Bay Area bridges because local bridge retrofit projects are being funded partly by a pool of money collected from tolls.
Only one contractor bid in 2004 to build the self-anchored suspension bridge: The bid was twice as much as had been anticipated and the expected final cost continues to climb.
In June 1997, a Caltrans advisory panel estimated that the east span would cost $1 billion if the entire bridge were built as a skyway.
It would cost up to $340 million more to incorporate a self-anchored suspension bridge or similar-looking section into the design, Caltrans’ panel of advisors said.
But the latest official project update shows that the self-anchored suspension bridge alone will cost $2.3 billion. The entire east span replacement project is forecast to cost more than $6 billion.
Additionally, a 15-month delay in the first shipment from China to Oakland of steel pieces for the self-anchored suspension bridge, which arrived in January, was caused by “the complexity of the design and fabrication,” according to a December project update published by Caltrans.
“This is a very tough bridge to build — that’s all there is to it,” program manager Tony Anziano said during a recent hearing. “It’s not an erection challenge. It’s a fabrication challenge because of the size and complexity of the bridge.”
The self-anchored span could be ready by 2013 and needed connectors could be in place to allow a grand bridge opening by late 2014, which is a decade behind schedule, according to the December report.
Until the new bridge opens, motorists traveling between Oakland and San Francisco must slow down from 50 mph to 40 mph to avoid crashing or flipping off a temporary S-curve that was installed during Labor Day weekend as part of the rebuilding project.
Bridge officials blame many of the delays on land disputes with the Navy and other organizations that forced Caltrans to build the self-anchored suspension bridge towards the end of the east span project, instead of at the start.
“If we had been able to build it according to the original strategy, west to east, we could have gotten the SAS strategy underway many years before,” Bay Area Toll Authority executive director Steve Heminger said during a recent hearing.
Embracing the unconventional
The eastern and western spans of the Bay Bridge were built in the 1930s using contrasting designs — but neither span incorporated an unconventional feature designed to beautify the new east span.
The western span and the Golden Gate Bridge, which have withstood all major earthquakes, were built using a conventional suspension bridge design.
But the much-longer eastern span of the Bay Bridge, which has proved vulnerable to earthquakes, was built in the 1930s as an elevated roadway held in place by robust towers driven deep into the muddy Bay floor.
Most of the eastern span has already been rebuilt as a more modern, attractive elevated roadway than the span that it will replace.
But the so-called skyway remains unused while work to connect it with Yerba Buena Island using a self-anchored suspension bridge continues.
Self-anchored suspension bridges use just one single support tower, and the 2,050-foot stretch being built will be the longest in the world.
Instead of anchoring overhead cables into the ground, cables in self-anchored suspension bridges are wrapped above and below the bridge and then bound together.
Because it is impossible to hoist road segments onto such a bridge during construction, Caltrans contractors are building a temporary bridge, upon which the permanent bridge will be laid.
– 280,000: Commuters daily
– $4: Current cost to cross the bridge
– $6: Cost to cross bridge at peak time July 1
– 1936: Year Bay Bridge opened
– 2004: Original planned date of completion for rebuild
– 2014: Current planned date of completion for rebuild
Bay Bridge timeline
– October 1989: Loma Prieta earthquake kills motorist on the east span of the Bay Bridge.
– May 1990: “Competing Against Time,” a report by a panel of experts, recommends California place a high priority on seismically retrofitting its bridges.
– September 1992: UC Berkeley team estimates retrofit of east span would cost up to $200 million.
– Summer 1995: Caltrans’ Seismic Advisory Board suggests replacing rather than retrofitting the Bay Bridge due to likely high costs of retrofitting. Caltrans begins designing replacement spans.
– December 1996: Consultant report recommends replacement over retrofit. It estimates the cost at $843 million for a bridge that includes a single tower. Two Caltrans panels recommend building a new eastern span, saying it will be safer and more economical than a retrofit.
– February 1997: Gov. Pete Wilson announces the eastern span will be rebuilt.
– May 1997: Caltrans Engineering and Design Advisory Panel holds workshop to review design alternatives and narrows options to a viaduct bridge with no towers or decorated with one of two types of single-towered bridges. Final decision postponed for a year.
– May 1998: Panel recommends incorporating a self-anchored suspension bridge into eastern span, which would cost
– June 1998: Metropolitan Transportation Commission approves bridge design.
– February 1999: San Francisco and UC Professor Abolhassan Astaneh-Asl objects to the design. Astaneh-Asl says the bridge wouldn’t withstand a major earthquake.
– January 2002: At eastern span project groundbreaking, Caltrans says span will open in 2007.
– June 2002: Caltrans says eastern span will open in 2009.
– March 2003: Caltrans increases eastern span cost estimate to $3 billion, citing the unique scale and complexity of the project.
– May 2004: Single bid received to build a self-anchored suspension bridge at a cost up to $1.8 billion, which is double Caltrans’ $730 million estimate.
– August 2004: Eastern span cost estimated at $5.1 billion, with $1.3 billion in overruns blamed on self-anchored suspension bridge.
– December 2009: Eastern span cost estimated at $6.3 billion, including $2.3 billion for self-anchored suspension bridge. Bridge opening forecast for 2014.
– January 2010: First shipment of steel parts arrives 18 months late for self-anchored suspension bridge. Delay blamed on complexity of design.
Source: Caltrans, California State Library
Famous suspension bridges
Suspension bridges, not self-anchored, used as inspiration for the iconic redesign of the Bay Bridge’s eastern span:
– Golden Gate Bridge
– Western span of Bay Bridge
– Brooklyn Bridge, New York
– Great Belt Bridge, Denmark
– Tsing Ma Bridge, Hong Kong
– George Washington Bridge, N.Y.
– Lions’ Gate Bridge, Canada
– Humber Bridge, England, U.K.
– Tacoma Narrows Bridge, Wash.
– Akashi-Kaiky Bridge, Japan