Progressive bolt failure likely cause of pipe break in Boston
Progressive bolt failure likely cause of pipe break in Boston
(OP)
The failure analysis report was recently released for the pipe break that disrupted the city of Boston's water supply last May. It is a good piece of forensic engineering by the authors, who had little to go by.
htt p://www.mw ra.state.m a.us/01new s/2011/052 511-panelr eport.html
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RE: Progressive bolt failure likely cause of pipe break in Boston
I'm no metallurgist, but the fact that the bolts were "zinc plated" caught my eye. I know that other high strength bolting materials are susceptible to embrittlement when hot dip galvanized Could this have something to do with it? I did some very cursory research on A193 material embrittlement due to HDG, but the answers were contradictory.
RE: Progressive bolt failure likely cause of pipe break in Boston
RE: Progressive bolt failure likely cause of pipe break in Boston
I understand that zinc plated isn't the same as HDG, but it's a common mistake to confuse the two, so I thought maybe the authors did.
RE: Progressive bolt failure likely cause of pipe break in Boston
RE: Progressive bolt failure likely cause of pipe break in Boston
What I take away fom this is that the devil is in the details with tension connections. Over time, the tension will exploit any flaws and lead to a failure. Reinforces the principle for providing redundancy in tension connections to insure against these manufacturing, installation and mother nature factors that engineers cannot usually control.
Another example of this would be the Big Dig tunnel roof panel collapse.
RE: Progressive bolt failure likely cause of pipe break in Boston
their conclusions in one page and presented back-up evidence in an Appendix.
Anyway, one would assume that Victaulic would have also supplied the bolts and inspected and approved the installation as the integrity of their product is highly dependent on this.
What surprised me was not making an "empty pipe" one of the design conditions.....