Step-by-step guide to Oakland Bay Bridge repairs

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As of today, it's still closed.First off, I don't have anything to do with the bridge or its repair, just thought we might like to follow along.From: http://www.kron.com/News/SpecialCove...6/Default.aspxAttachment 40885"Thursday on the KRON 4 Morning News, Caltrans spokesman Bart Ney got out some diagrams of the bridge and a Sharpie and walked KRON 4's Darya Folsom through the process the transit agency is going through in making repairs to the Bay Bridge.  This is a step-by-step guide to the process with Ney's diagrams and in his own words."From: http://baybridgeinfo.org/Attachment 40887Last edited by denrep; 10-19-2010 at 11:42 PM.
Reply:So basically they didn't replace that cracked I bar, they put in a couple of rods along side it to hold what it couldn't and their temp job popped off because they "tacked" it?? Is that what I'm reading there? Or maybe those rods aren't 'temporary'.
Reply:Originally Posted by SandySo basically they didn't replace that cracked I bar, they put in a couple of rods along side it to hold what it couldn't and their temp job popped off because they "tacked" it?? Is that what I'm reading there?
Reply:"The pieces that broke were part of major repairs done Labor Day weekend after state inspectors found a crack on a key structural beam. Those fixes failed due to vibrations caused by high winds."
Reply:Hmmm:Attachment 40935Attachment 40934Last edited by denrep; 10-19-2010 at 11:42 PM.
Reply:So I take it this is where the support member cracked and was repaired."Enhanced Welds"  New term for doing it right?Last edited by duaneb55; 10-31-2009 at 09:39 PM.MM200 w/Spoolmatic 1Syncrowave 180SDBobcat 225G Plus - LP/NGMUTT Suitcase WirefeederWC-1S/Spoolmatic 1HF-251D-1PakMaster 100XL '68 Red Face Code #6633 projectStar Jet 21-110Save Second Base!
Reply:Originally Posted by duaneb55So I take it this is where the support member cracked and was repaired.
Reply:Those are some serious pieces of steel.  Look to be about 24oz to the pound.  Must have been interesting to see them placed.MM200 w/Spoolmatic 1Syncrowave 180SDBobcat 225G Plus - LP/NGMUTT Suitcase WirefeederWC-1S/Spoolmatic 1HF-251D-1PakMaster 100XL '68 Red Face Code #6633 projectStar Jet 21-110Save Second Base!
Reply:Yeh the original defect was a crack one of those dog bones. They call them "eyebars".  Anyway they find a crack in the dog bone, put up temporary re-inforcement, and the re-inforcement fell off.
Reply:Originally Posted by duaneb55So I take it this is where the support member cracked and was repaired."Enhanced Welds"  New term for doing it right?
Reply:So what we're looking at is intended to be a permanent repair?MM200 w/Spoolmatic 1Syncrowave 180SDBobcat 225G Plus - LP/NGMUTT Suitcase WirefeederWC-1S/Spoolmatic 1HF-251D-1PakMaster 100XL '68 Red Face Code #6633 projectStar Jet 21-110Save Second Base!
Reply:This link was posted on the AWS site yesterday.http://www.sfgate.com/cgi-bin/object...0500771088.jpgpicture #2 shows the link with the crack.Charlie
Reply:"Bay Bridge To Remain Closed Monday"From: http://www.nbcbayarea.com/news/local...-68382392.html"The California Department of Transportation still has no official estimate for when the San Francisco-Oakland Bay Bridge will reopen, but it will not be open in time for the Monday morning commute.The crews are having problems getting an exact alignment of a huge screw type cylinders into a series of metal plates or eyebars  They can't get them to fit correctly so that there is no metal on metal contact."That's easy enough to believe.Do we have a bridge man on staff?What's with the complex repair anyway?Could it be this complicated to just change the eyebar out? Or stack a repair plate on the cracked eye? I have to admit that I wonder why a replacement eyebar wasn't on the burning table as soon as the original failure occurred. There must be blueprints, unless they burned 'em to stay warm in the toll-booth. The eyebar looks like a simple piece, and the rods used in the patch don't seem to add up to the same crosssection as the broken link. I wonder why a plate patch wasn't used? I wish they'd put a dollar in the picture so we could get a feel for the size of things. I'm no bridge engineer, but I can't imagine any other system that uses eyebars, such as  a large press, or a large mechanical linkage, which would be repaired with a tie-rod patch rather than rebuilding or replacing the original part.When the bridge is open, it rings the cash register for over $100,000.00 per day! I guess I don't understand how a replacement eyebar of the time-proven design wouldn't be justified at practically any cost. Who knows what unknowns the patch is imposing on the rest of the structure. Seems like there could be other weak eyebars; may as well face it and develop a system to change them out. Plus Alfred wants the old eyebar and repair saddle for the post-driver.  Good LuckLast edited by denrep; 11-01-2009 at 08:50 PM.
Reply:My guess is that it's hard to unload the tension from the eyebar in order to replace it. It was most likely installed prior to all the deck members and road surface.  How does one easily lift a bridge, and where do you attach your lifting cables? My guess is that the steel being used for the repair is of greater tensile strength compared to the original member, so they can reduce the size. It does seam like a goofy F'd up way to do a repair however.As far as a comment of a permanent repair, thats happening right next door from what I understand. They are in the process of building a new bridge at which time this one will be demolished / dismantled..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:So one could conclude the repair was the less expensive option to just buy them time to finish the new bridge.MM200 w/Spoolmatic 1Syncrowave 180SDBobcat 225G Plus - LP/NGMUTT Suitcase WirefeederWC-1S/Spoolmatic 1HF-251D-1PakMaster 100XL '68 Red Face Code #6633 projectStar Jet 21-110Save Second Base!
Reply:I really wonder why another plate couldn't be stacked on the eyebar?Attachment 40984Last edited by denrep; 10-19-2010 at 11:42 PM.
Reply:Originally Posted by denrepI really wonder why another plate couldn't be stacked on the eyebar?Attachment 40984
Reply:Here's a pretty good link for those of you with an understanding of these things. I'm still stumbling through it. Probably won't get too good a grip on it tho.  Looks like not all the eyebars are the same length. Lotsa pics.http://www.sci-experiments.com/Broke...kenBridge.html
Reply:I really wonder why another plate couldn't be stacked on the eyebar?
Reply:Originally Posted by jsfabProbably because it would've required welding to the thinnest part of the dogbone (the long part) , thus creating a new stress point for the next crack to start. . . .
Reply:That's a pretty good link, Sandy.
Reply:Originally Posted by denrepI wonder how thick the "dogbone" is?
Reply:Whew, I thought at first you were talking about the GG bridge, last time I seen it it had one of my engineering school's bugs hanging from it! But I did drive across the Oakland bridge a few times when I was working in Fresno...and they made me pay EVERY time!!!!!!!!!!!!!!!
Reply:It's truly amazing how over built these older bridges really are. Think about bridges like the Brooklyn Bridge, the Golden Gate Bridge and hundreds of others. There is no way they could have predicted the volume and weight of traffic these bridges carry today. Yet these bridges are still in use day after day with no restrictions in general. This bar cracked, and cracked severely, yet the bridge was still standing, in use and did not fail. It took a visual check to notice the problem..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:Civil engineering projects usually have a design factor of safety of like 5 or 10. Aircraft? 1.2 to 1.5!!!Ya know,  That "eyebar" in the pic in Post#16 kind of reminds me of a skip-link chain section.Anyway, yes public projects often -do- call for a factor of safety ('overdesign') of 5-10, precisely because when a lot of the 'codes' and guidelines were formulated they didn't know or weren't able to precisely measure the actual (varying) service load stresses in the structures.  Add in wind and seismic variations, and things can get even trickier.Aircraft with a 1.5 FS?  More like 1.1-1.2 and inspect OFTEN!  That said, the 'fix' looks like an ugly kludge!  And trying to make spherical pockets and nuts?  WTF!  Did somebody think they'll get much of a spherical bearing out of plain (soon-to-be-rusty because of the moisture and salt on a BRIDGE!) steel compressing on plain steel?  If there's compression between the nut and the pocket, then they are pretty much locked together as far as bending goes.  If there is so little compression between the nut and the pocket that there is movement, then it will loosen up.  If there is movement possible, the joint will fret and chew itself up.  Kludge!My fix?  New beefed-up eyebar section scarfed and fish-plated onto existing eyebar at least 10x the pin dimension -away- from the pin area.  FULL penetration welds, seismic-code applies to materials and welding, not tack welds!  And maybe put some grease zerks on the pins/bushing holding the eyebar sections together.  Oh, and the bridge is supposedly reopened today Monday Nov 2 (per the link from Sandy), as of 10AM PST.  The best laid schemes ... Gang oft agley ...
Reply:Originally Posted by MoonRiseThat said, the 'fix' looks like an ugly kludge!  And trying to make spherical pockets and nuts?  WTF!  Did somebody think they'll get much of a spherical bearing out of plain (soon-to-be-rusty because of the moisture and salt on a BRIDGE!) steel compressing on plain steel?  If there's compression between the nut and the pocket, then they are pretty much locked together as far as bending goes.  If there is so little compression between the nut and the pocket that there is movement, then it will loosen up.  If there is movement possible, the joint will fret and chew itself up.  Kludge!
Reply:This is definitely complex. I guess I could see the potential toggle effect, but that's also what gives the saddle its equalizing qualities.  But once it's assembled, and in tension, with the saddle halves tied together, and tightly against the bone, could there be any toggle action without failure?Enlpck - Why do you suppose this repair was chosen over either bone replacement, or a stacked plate repair?Good Luck
Reply:I read somewhere, that we no longer have the mill capacity to recreate the beams used in the Golden Gate, or Bay Bridge.  We shipped the stuff to China (true) when the particular plants were closed."Unloading" the eye would be a definite problem, but couldn't it be done with the same FUBAR arrangement being used to "repair" the eye?  Tension on the member while scab/fish plates are installed?I don't know about stress risers, but it sure seems that plate would outlast what they are doing"Any day above ground is a good day"http://www.farmersamm.com/
Reply:What sort of built up fillet would be enough to compensate for the lack of full, real, thru the steel bolting?A friend of mine  told me that bolts are often used on structural steel due to welding's inability to penetrate the member all the way through, and in the middle of the joint.  Welding only (unless you consider plug welding) attaches the edges of the plate"Any day above ground is a good day"http://www.farmersamm.com/
Reply:Another thing I was wondering...................Could the eye be truly imobilized (remember the wind sway on the bridge) in order to properly weld it?"Any day above ground is a good day"http://www.farmersamm.com/
Reply:Just a couple of observations, related to Denrep's questions.First, replacing the dogbone ....   cost and time.  How long would it take, to get one made?  PLUS, you would somehow have to take the load off members involved, to drive pins out, and replace the part.   What does that huge crane cost, per day???   And more importantly, where is it now?Looking at that crack, it's opened up at least as much as the thickness of the steel.   Assume two inches, if not more.   Looking at the connection, if that crack opened up two inches, the dogbone next to it also stretched that much.  The opposite two dogbones also probably elongated somewhat.   It would be very difficult, to engineer, and make, a new dogbone, correct length, that ALL four of those dogbones, would only hold 1/4 of the tension each.  Remember, also, considering the length, temperature and expansion/contraction will also be a factor.   Engineer in SF, calling China "it's 50 degrees right now .....   60 degrees over there????   What's the steel temperature?"   I can see this going on and on.   73 years later, with all the stresses and corrosion since, I doubt going back to the original engineering drawings would do any good.   Something I never saw mentioned in all the critiques .....  the fact that those dog-bones will heat and cool much slower than the rods will .....   which means the rods might tighten up more, thus holding more pressure, or loosen up slightly, allowing the "tacked" on crossbar to fall off.  Granted, the SF bay doesn't have fast, or great, changes in temperature normally, but in a case like this, probably doesn't take much for the rods vs. dogbones length to change enough to allow that crossbar to fall off.Hopefully, this time, with the "enhanced welding"  at least everything will stay in place.
Reply:Originally Posted by jsfabJust a couple of observations, related to Denrep's questions.First, replacing the dogbone ....   cost and time.  How long would it take, to get one made?. . .
Reply:Probably off topic, but it was built in the days of FDR.  Same with the Hoover Dam.  The days of true public works projects that have withstood the test of time.I have a sneaking suspicion that the same men could have come up with a solution.Sorry for the interuption.....carry on"Any day above ground is a good day"http://www.farmersamm.com/
Reply:They already tried to kludge it once.  It failed PDQ.Now they are trying to kludge the kludge.  Time to failure, anyone?Trying to take a shortcut means it takes more time and money to go back and fix it the right way.Use the tension rods and the funky clamps as a TEMPORARY fixture/jig/tool while the dogbone is replaced, either in part or in total.  It's just steel, and not -that- dang thick.  The best laid schemes ... Gang oft agley ...
Reply:They got lucky on the first failure.  Next one just might kill someone.MM200 w/Spoolmatic 1Syncrowave 180SDBobcat 225G Plus - LP/NGMUTT Suitcase WirefeederWC-1S/Spoolmatic 1HF-251D-1PakMaster 100XL '68 Red Face Code #6633 projectStar Jet 21-110Save Second Base!
Reply:Just another scenario that no one can train you for.MikeConstans Fides et IntegritasLincoln Weldanpower 150 ACAirco Aircomatic MIGet CAV II w/ spoolgunMillermatic 30a wirefeeder
Reply:I sure hope that while the repair is going on that they are inspecting the rest. Not just visually, the whole high tech method, plus some accurate measuring to see what else is happening.
Reply:WOW thanks for posting the pics.      My books are in storage, but there was a bridge like that that failed when an eyebar cracked. Dropped the whole thing. the only reason this hasn't fallen yet is that there were the 4 links instead of one. It was designed to have a lot of redundancy. But in this case I would worry that age and the probably increased  dead weight of bridge pavement etc is not on the bridge engineers side. They should have use twice as many threaded rods, to allow for a partial failure of the repair.  And the center saddle against the pin puts the pin on bending, it was only designed for shear. I don't know the design loading would have been, but that old steel doesn't generally get more ductile with age. my fear is that the engineer in charge is thinking he can use 100% of yield on these rods, and it is plain he has not allowed for partial failure of his repair. Unloading and then reloading this joint could be worse than not touching it at all.         As for replacing the eyebar, if I remember right these bridges usually were assembled hot. The pin was iced and the eye heated, they were not meant to rotate, only to provide a reasonable means of making up a long enough bar. If that is the case the failure could be partly due to too tight a fit 80 years ago. And the remaining bars could have significant fatigue as well. if the fit was a bit loose, then water could have gotten in, and the corrosion products taking up more space, further straining the eye, plus the intergranular corrosion would lead to stress corrosion cracking that tosses out any predictability.      I don't know, but I hope these guys (the engineers) are smarter than this repair looks. This could get worse before it gets over.past work toys; lathes,mills, drills, saws,  robots, lasers ironworker, shears, brake, press, grinders, tensile tester,  torches, tigs, migs, sticks, platten table, positioner,  plasmas , gleeble and spot. Retired June 30, 2009.
Reply:Originally Posted by denrepHow long? One shift at US Steel's Gary Works. Probably where the eyebar came from to begin with. We don't know the dimensions of the eyebars, but I'll accept your 2" guess. Whatever, they were within range of early 1930's mill, fabrication, transportation and erection methods, so they shouldn't be too difficult to duplicate.They look like a simple shape that could be burned from plate. If we're worried about matching dimensions, cut a set of four.Cost? This cash cow has been milked for over a 100 G a day, for years!  We can't afford a proper and prompt fix?Good Luck
Reply:I think JS cut thru the fog on this one.It makes sense that any new eye would be of a different dimension taking into account wear and stretching of the remaining eyes.  I couldn't see that, and he did.I dunno if there's a way to compensate for the dimensional differences.All four dogbones were loaded equally when the thing was built.Would a combination of rigging to the towers, and a barge below, be adequate to unload the tension during repair?  Would be a lot of potential movement."Any day above ground is a good day"http://www.farmersamm.com/
Reply:Originally Posted by 59halfstepThese were from a group of pictures of a '50's machine shop of a ship building site, posted on another welding site.  They are cutting a web of the engine crank shaft.  Seems as though they could burn out a new link and weld it on to the old one.http://www.shipsnostalgia.com/guides/William_Doxford_and_Sons#The_Manufacturing_Process
Reply:....Well....I live in Sacramento, just an hour from the bridge.......and yes the same pics of the 'repairs' are in the local newspaper ( www.SacBee.com ) and the T.V.....and from what I understand...the rods got to flapping around in the wind, cracked/broke at the ends, due to not having the later added sperical nuts/washers....those 'rods' are something like 100 feet long...you'd think they'd have supported them in a few places....just some rope would have done it.....everybody knows it's windy around there....  And yes, there's another newer, and hopefully better, bridge being built next to this one.....partly by MCM construction...here in Sacramento....they do bridge stuff....C.C. Meyers here in Sacramento fixes the busted up freeways....I hope they get along well....   But having lived in California 58 years...and driving around here for 46 or so....Cal Trans does do some stuff that seems a little thoughtless.....like building N/S I-5 through Sacramento at a level lower than the adjacent Sacramento River....just separated by the levee.....which is why that part of I-5 is called the 'boat' section.....because that's how your car/pick-up behaves when the levee leaks, or it rains and the drains get clogged...like it did a couple weeks ago....a foot deep or more of water for maybe 200 yards...on the interstate....on both sides.............that'll slow ya' down.....Dougspair
Reply:Nice pics of guy cutting that plate....I see he did the right thing, drilled pilot hole for starting the inner circle....I always drill a pilot....even in 1/4" stuff....keeps the tips clean, gets fast pre-heat and cut  starting....takes a few minutes to drill in the heavier stuff...but still less time than cleaning the tips, and beating the slag off the bottom....and hardly anything to grind either...I kept a mag-base with long drill bit just for that plate stuff....hardly any slag....the small bit that was...just tap away with tomahawk...bottom of cuts usually looked as clean as the top...    Last 2 places I was at...7 years between the two....spent maybe 3 days a week cutting plate from 1/4" up to 8"...used Koike optical pattern tracer....25-30 year old stuff but still works fine,  like the one I used back in 1980....machines cost more than the ....  Couple other places had the magnetic follower like in the pics...you have to make a pattern out of steel, usually at least 1/8" thick....and compensate there, for the diameter of follower tip...outside corners of burned stuff always rounded off too....for me...the magnetic followers are good for circles and large radii...like the guy in the pics is doing..And he's got just the right cutting going on...nice shower of sparks...no big globs dropping offa' there.....looking at the sparks...best way to see what's going on with your speed settings...Dougspair
Reply:....And....while I'm at it......I cut plenty of Stainless plate up to 3/4" with plasma torch and Hypertherm power supply.........using same optical follower....and you better believe I drilled a 1/8-3/16" pilot for the $30-40 dollar plasma tips to start....piercing in plate is the main wear factor on plasma stuff....a couple pierces in 1/2" stainless is like cutting 10-12 lineal feet....blasts slag into the tip, just like oxy/acet does when piercing.....   I've never used a laser myself, but from what I read in the various 'zines, and couple people here that do have them........piercing there is also a huge problem....   Where I work now, I'm maint guy...but we have a 1992 model Lockformer Vulcan 9000, CNC 2 axis....has 2, 5X10 foot tables...load one while the other is cutting...we only cut galvanized light gauge steel (HVAC work) ....26-16 gauge....one torch....still, piercing is hard on it....blows slag/melted zinc up into the nozzle, and tends to clog up the 5-ball sheet-follower on the torch....  We try to layout and nest stuff so the piercings come from all different directions....seems to keep the nozzle from getting out of round....when I started there 3-1/2 years ago...all starts were always from the same back left corner....nozzles/tips lasted a 2-days, maybe 3...and had a big 'notch' burned  to the same side all the time...now with my suggestion of different directions...we can get maybe two weeks out of the same tip/nozzle. You can program the cuts on the computer to start where-ever you want...but if you don't...they always default to the back-rear corner...   OK....I'm done for today....well, except for this...when built...the Golden Gate Bridge paid for itself in less than two years after opening for traffic....so where is all that money going now? I guess a little goes to the full-time painting/re-painting crew.........likely the same deal with these other 'pay' bridges.....  Want to know more about bridges??....I designed and built two of them....both cross creeks 45-50 feet long...9 feet wide...support any road going vehicle including log trucks....can be seen from Google earth....one south of Shingle Springs in California here, one up in Yreka....next post I'll maybe include the locations in longitude/latitude....if anyone asks...Dougspair
Reply:I can tell you from people on the ground that the ACTUAL people doing the work during version 1.0 said that it was terribly under designed and destine to fail.    Their real world experience was scoffed at and the college educated fokes took over.Vantage 500's LN-25's, VI-400's, cobramatics, Miller migs, synch 350 LX, Powcon inverters, XMT's, 250 Ton Acurrpress 12' brake, 1/4" 10' Atlantic shear,Koikie plasma table W/ esab plasmas. marvel & hyd-mech saws, pirrana & metal muncher punches.
Reply:Originally Posted by jsfabJust a couple of observations, related to Denrep's questions.First, replacing the dogbone ....   cost and time.  How long would it take, to get one made?  PLUS, you would somehow have to take the load off members involved, to drive pins out, and replace the part.   What does that huge crane cost, per day???   And more importantly, where is it now?Looking at that crack, it's opened up at least as much as the thickness of the steel.   Assume two inches, if not more.   Looking at the connection, if that crack opened up two inches, the dogbone next to it also stretched that much.  The opposite two dogbones also probably elongated somewhat.   It would be very difficult, to engineer, and make, a new dogbone, correct length, that ALL four of those dogbones, would only hold 1/4 of the tension each.  Remember, also, considering the length, temperature and expansion/contraction will also be a factor.   Engineer in SF, calling China "it's 50 degrees right now .....   60 degrees over there????   What's the steel temperature?"   I can see this going on and on.   73 years later, with all the stresses and corrosion since, I doubt going back to the original engineering drawings would do any good.   Something I never saw mentioned in all the critiques .....  the fact that those dog-bones will heat and cool much slower than the rods will .....   which means the rods might tighten up more, thus holding more pressure, or loosen up slightly, allowing the "tacked" on crossbar to fall off.  Granted, the SF bay doesn't have fast, or great, changes in temperature normally, but in a case like this, probably doesn't take much for the rods vs. dogbones length to change enough to allow that crossbar to fall off.Hopefully, this time, with the "enhanced welding"  at least everything will stay in place.
Reply:As far as welding on a patch plate, don't forget, we don't know what grade material the originals were, what their carbon/alloy content was, or given it's age, what the sulfur content was of that steel.  It is very possible that the material does not lend itself well to welding, particularly without substantial pre/PWHT, which you're not going to perform on a loaded structure.
Reply:Originally Posted by jsfab.   What does that huge crane cost, per day???   And more importantly, where is it now?
Reply:A couple days ago I was on the telephone placing a parts order, when the rep told me he was in Oakland, I asked about the bridge. Surprisingly, the rep was very knowledgeable about  the local bridges and their history, and seemed happy to talk about them.He told me that the underlying problem with the bridge span we're discussing here, and why it must be replaced, is that it has -I'm not kidding- a wooden foundation! When I questioned him on the wood,  he went on in length with details of how and why. You learn something every day! Good Luck