BTinSF
Aug 30, 2009, 4:36 PM
Trickiest Bay Bridge work begins Thursday night
Rachel Gordon, Chronicle Staff Writer
Sunday, August 30, 2009
The most complex procedure on the Bay Bridge replacement project begins Thursday night when the entire span will be shut to traffic as crews slice away a football field-size section of the double-deck roadway and slide in a prefabricated replacement - 150 feet in the air.
http://imgs.sfgate.com/c/pictures/2009/08/29/ba-baybridge0830_SFCG1251433114.jpg
The cost of the ambitious project just east of Yerba Buena Island has jumped from $34 million to $140 million, or more than 400 percent, in just two years.
The eastern tie-in, as the project is known, is just one component of replacing the seismically unstable bridge and the latest whose price has soared.
Several factors, including rising steel prices and an accelerated construction schedule, have contributed to escalated expenses, transportation officials said.
But the biggest cost driver: major design changes that came after engineers determined more could and should be done to prevent the bridge from collapsing in a major earthquake, said Caltrans spokesman Bart Ney.
After all, it was the destructive force of the Loma Prieta earthquake 20 years ago that proved the Depression-era Bay Bridge was not fail-proof.
Engineers revisited earlier concerns that fell to the wayside when the project bid came in, Ney said.
"We did not like the risks we saw," Ney said. Supporting beams and columns were made more robust and other changes were made, for example, "so old steel didn't connect to new steel," which helps reduce the potential for collapse, Ney said.
Scott Haggerty, an Alameda County supervisor who chairs the Bay Area Toll Authority, which shares oversight of the bridge replacement project with Caltrans and the California Transportation Commission, said the higher price will be worth it.
"Yes, the cost is higher than the original estimates, but we need to remain focused on why we're doing this project. We're doing this because we want a safer bridge, a stronger bridge that will survive an earthquake," he said.
Haggerty described as "flawed" the original cost estimates for the project.
"Quite frankly," Haggerty said, "you can't even build most roads over dirt for that cost."
The eastern tie-in project is a component of the temporary detour connecting Yerba Buena Island and Oakland that motorists will use while the more elegant single-tower suspension span is being built.
The highly choreographed maneuver set for the Labor Day weekend will entail crews using saws and blow torches to cut away a 288-foot section of the bridge before it is rolled away on a specially designed set of rails, and later demolished. A new piece will be rolled in using the same rail system.
http://imgs.sfgate.com/c/pictures/2009/08/29/mn-baybridge30_p_0500529597.jpg
A temporary section of the Bay Bridge will be inserted over Labor Day weekend.
http://imgs.sfgate.com/c/pictures/2009/08/29/mn-baybridge30_p_0500529684.jpg
A worker walks on top of the section that will temporarily connect drivers to a detour while new construction ties the bridge to the Yerba Buena tunnel.
http://imgs.sfgate.com/c/pictures/2009/08/29/mn-baybridge30_p_0500529598.jpg
Technicians set up a hydraulic system that will be used to slide the old section out and the new temporary 300-foot section in on the Bay Bridge.
http://imgs.sfgate.com/c/pictures/2009/08/29/mn-baybridge30_p_0500529609.jpg
A 300-foot double-desk section of the Bay Bridge east of Yerba Buena Island Tunnel left will be cut and slid away on Labor Day weekend. The new temporary replacement right will be slid into place allowing for the removal of the old span. The new detour will be a slightly different drive as the roadway curves to the south, requiring drivers to slow down while approaching or leaving the tunnel. Aug 26, 2009.
The precision work, to be performed 10 stories above ground, involves moving 6,900 tons of steel and concrete. The bypass, scheduled to be reopened to traffic by 5 a.m. on Sept. 8 at the end of the Labor Day weekend, will be used for three or four years by the 260,000 vehicles that travel the bridge daily.
Just as the price of the east tie-in portion has escalated, so, too, has the overall Yerba Buena detour project of which it is a part. The original cost estimate was $132 million, a fraction of the $526.7 million now projected. And that represents just a part of the larger cost to replace the entire eastern span of the bridge.
In 2004, the state auditor criticized Caltrans for underestimating the cost of building the new span, when the price went from $2.6 billion to $5.1 billion over a three-year period. In the five years since, the cost has increased another $1.1 billion, to $6.2 billion. Bridge toll revenue and state tax money are funding the project. Work is scheduled for completion in 2013.
E-mail Rachel Gordon at rgordon@sfchronicle.com.
Source: http://sfgate.com/cgi-bin/article.cgi?f=/c/a/2009/08/30/MNL119F93K.DTL
Rachel Gordon, Chronicle Staff Writer
Sunday, August 30, 2009
The most complex procedure on the Bay Bridge replacement project begins Thursday night when the entire span will be shut to traffic as crews slice away a football field-size section of the double-deck roadway and slide in a prefabricated replacement - 150 feet in the air.
http://imgs.sfgate.com/c/pictures/2009/08/29/ba-baybridge0830_SFCG1251433114.jpg
The cost of the ambitious project just east of Yerba Buena Island has jumped from $34 million to $140 million, or more than 400 percent, in just two years.
The eastern tie-in, as the project is known, is just one component of replacing the seismically unstable bridge and the latest whose price has soared.
Several factors, including rising steel prices and an accelerated construction schedule, have contributed to escalated expenses, transportation officials said.
But the biggest cost driver: major design changes that came after engineers determined more could and should be done to prevent the bridge from collapsing in a major earthquake, said Caltrans spokesman Bart Ney.
After all, it was the destructive force of the Loma Prieta earthquake 20 years ago that proved the Depression-era Bay Bridge was not fail-proof.
Engineers revisited earlier concerns that fell to the wayside when the project bid came in, Ney said.
"We did not like the risks we saw," Ney said. Supporting beams and columns were made more robust and other changes were made, for example, "so old steel didn't connect to new steel," which helps reduce the potential for collapse, Ney said.
Scott Haggerty, an Alameda County supervisor who chairs the Bay Area Toll Authority, which shares oversight of the bridge replacement project with Caltrans and the California Transportation Commission, said the higher price will be worth it.
"Yes, the cost is higher than the original estimates, but we need to remain focused on why we're doing this project. We're doing this because we want a safer bridge, a stronger bridge that will survive an earthquake," he said.
Haggerty described as "flawed" the original cost estimates for the project.
"Quite frankly," Haggerty said, "you can't even build most roads over dirt for that cost."
The eastern tie-in project is a component of the temporary detour connecting Yerba Buena Island and Oakland that motorists will use while the more elegant single-tower suspension span is being built.
The highly choreographed maneuver set for the Labor Day weekend will entail crews using saws and blow torches to cut away a 288-foot section of the bridge before it is rolled away on a specially designed set of rails, and later demolished. A new piece will be rolled in using the same rail system.
http://imgs.sfgate.com/c/pictures/2009/08/29/mn-baybridge30_p_0500529597.jpg
A temporary section of the Bay Bridge will be inserted over Labor Day weekend.
http://imgs.sfgate.com/c/pictures/2009/08/29/mn-baybridge30_p_0500529684.jpg
A worker walks on top of the section that will temporarily connect drivers to a detour while new construction ties the bridge to the Yerba Buena tunnel.
http://imgs.sfgate.com/c/pictures/2009/08/29/mn-baybridge30_p_0500529598.jpg
Technicians set up a hydraulic system that will be used to slide the old section out and the new temporary 300-foot section in on the Bay Bridge.
http://imgs.sfgate.com/c/pictures/2009/08/29/mn-baybridge30_p_0500529609.jpg
A 300-foot double-desk section of the Bay Bridge east of Yerba Buena Island Tunnel left will be cut and slid away on Labor Day weekend. The new temporary replacement right will be slid into place allowing for the removal of the old span. The new detour will be a slightly different drive as the roadway curves to the south, requiring drivers to slow down while approaching or leaving the tunnel. Aug 26, 2009.
The precision work, to be performed 10 stories above ground, involves moving 6,900 tons of steel and concrete. The bypass, scheduled to be reopened to traffic by 5 a.m. on Sept. 8 at the end of the Labor Day weekend, will be used for three or four years by the 260,000 vehicles that travel the bridge daily.
Just as the price of the east tie-in portion has escalated, so, too, has the overall Yerba Buena detour project of which it is a part. The original cost estimate was $132 million, a fraction of the $526.7 million now projected. And that represents just a part of the larger cost to replace the entire eastern span of the bridge.
In 2004, the state auditor criticized Caltrans for underestimating the cost of building the new span, when the price went from $2.6 billion to $5.1 billion over a three-year period. In the five years since, the cost has increased another $1.1 billion, to $6.2 billion. Bridge toll revenue and state tax money are funding the project. Work is scheduled for completion in 2013.
E-mail Rachel Gordon at rgordon@sfchronicle.com.
Source: http://sfgate.com/cgi-bin/article.cgi?f=/c/a/2009/08/30/MNL119F93K.DTL