Almost every day we see another newspaper headline like “More Problems for San Francisco’s New Bay Bridge Span”. It makes one wonder whether this bridge will be safe when opened. The answer is probably yes and no.
On the yes side is that it will probably hold up for auto traffic and the no side it probably won’t survive an earthquake intact. There are many reasons for this.
This is the most expensive public project in California history and yet we get one that is highly questionable safety-wise. In 1996 the cost estimate was $1.3 billion. Today it has skyrocketed to $6.4 billion. The retrofit of the existing bridge was estimated at $200 million.
The first problem was design selection. It was actually chosen for aesthetic reasons rather than safety. The Brown Brothers (Willy and Jerry) played a big role here. They wanted a “signature span.”
It has been criticized by some as both a less structurally robust design and with less predictable construction costs than other modern spans The Brown’s squabbling over design delayed the construction by at least two years and probably increased cost by a couple of billion dollars.
Can you believe a design contest was held for a “signature span” by the Engineering and Design Advisory Panel (EDAP) of the Metropolitan Transportation Commission (MTC)? Just like a beauty contest.
The retrofit of the San Francisco East Bay Bridge was supposed to cost $200 million. Today it has skyrocketed to $6.4 billion.
In the first months of construction at least one contractor was delivering recycled concrete. The issue faded quickly, swept under the rug by CalTrans? There was no report that any of this concrete was replaced.
On April 6, 2005, the FBI announced an investigation into charges by fifteen former welders and inspectors that welders were rushed to an extent affecting their performance on up to one third of the welds. Many of these welds are now embedded in concrete, some deeply underwater
In early November 2011, The Sacramento Bee newspaper reported and analyzed various reports (including “whistle-blower” statements) concerning the potential for falsified inspection reports associated with deep pile foundations. A technician who conducted key testing to ensure structural integrity of the span’s foundation was later disciplined for fabricating test results on other projects.
Now for the bolts.
“Three inch (7.5 cm) diameter bolts connect portions of the bridge deck mounting bosses to several concrete columns. There are 288 such bolts of various lengths. The bolts are tested in place by over tightening their retaining nuts. In the two weeks subsequent to this tightening, 30 of the first 96 bolts failed”. (KQED News)
The rods cannot be replaced as they are embedded in concrete and there is not enough clearance to remove them. Can’t you just hear these rods go “twang” as they break in the next earthquake?
So what we have here is a “signature span” that may be beautiful but is probably short on safety for many reasons:
- Questionable quality of concrete in base
- Questionable quality of welds now embedded in concrete
- Potential for falsified inspection reports associated with deep pile foundations
- Bolts that break when tightened. They cannot be replaced as they are embedded in concrete and there is not enough clearance to remove them
CalTrans insists the bridge is safe. If you believe them I have a bridge I will sell you – the eastern span of the Bay Bridge.
My suggestion – Let’s keep the old bridge (we have already spent millions on retrofit) and tear down the new one. We could recoup some of our $6.4 billion investment by selling the scrap metal. I understand scrap prices are high right now.