SACRAMENTO -- If the Loma Prieta earthquake were to strike again, the new eastern span of the Bay Bridge would be substantially safer than the 1936 cantilevered truss span motorists use today, according to new analysis presented to Bay Area legislators Thursday.
The 1989 Loma Prieta quake, a 7.1 temblor centered 60 miles southeast of the Bay Bridge, exceeded the original bridge's capacity to withstand the shaking, but it wouldn't have come close to taxing the new span, according to a line graph prepared by Caltrans bridge engineer Brian Maroney.
"Eighty years ago, engineers didn't understand or fully respect vibrations generated by an earthquake," Maroney said. "When you look at this line graph, it is easy to see why the eastern span failed in 1989."
Although bridge engineers have repeatedly assured the public that the new span is much safer than the old bridge, this comparison is the first side-by-side analysis Bay Area legislators have seen that shows how the old one fared during Loma Prieta and how the new one would handle a quake of similar magnitude and location.
The three agencies overseeing the Bay Bridge construction presented the new seismic comparison data to the Bay Area Caucus. Along with Senate Transportation Committee Chairman Mark DeSaulnier, D-Concord, the Bay Area lawmakers requested the briefing in the wake of mounting public concerns about the $6.4 billion span's seismic safety.
Much of the worry stems from
the failure of 32 high-strength steel bolts embedded in seismic stabilizers. The bolts snapped in early March, forcing Caltrans and the contractor, American Bridge/Fluor Joint Venture, to scramble to repair the damage."
and reassure the public that the other steel components are sound."
TAYD already involved with the Bay Bridge; not the most positive mention, but you know what they say about publicity:
thanks for the lesson in construction-you should be aware that I missed the game or should I say trouncing because of the interest in aforesaid. still think Taylor Devices fits into the equation because of the affiliations exemplified by information gleaned by perusing the presented facts. thanks