Small bridge

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Here's some guys fabricating a small bridgedeck. I'm only the customer representative (Province or State ) keeping an eye on the project.Steel is mainly S355J2G3 (bent sections C-quality)Deck plates are welded 'under powder' Rest is MIG with filled wire and the occasional small TIG job.Pictures are taken on the day of the leak testing of the closed sections.After welding the bridge is gridblasted and then coated with thermal spray (Aluminium).After that there's primer and 3 layers of coating. The deck of the bridge will only be covered in epoxy with gravel after the primer.
Reply:nice mig welding
Reply:Very Nice fabrication and welding.Co-Own CNC shop:Miller :1251 plasma cutter, MaxStar 700 TIG/Stick, & XMT 456 Multiprocess Welder.&  2 Hypertherm HPR260's Plasma CutterSorry I had a bad stroke but now I am back.
Reply:I'm guessing it's going across one of the smaller canals...... as I remember there were thousands and thousands of small bridges over there going over them.HH 187Miller Bluestar1EAHP AlphaTig 200X
Reply:very cool.  I like your work surface, or table, if you want to call it that -Graham-Mechanical EngineerAutosport Mechanic/Fabricator
Reply:looks like flux core to me.only thing worse than an ugly woman is an ugly weld
Reply:Originally Posted by spiral-cut-bevelvery cool.  I like your work surface, or table, if you want to call it that
Reply:Just wondering.Are the enclosed areas of the structure purged with something or spayed with some sort of corrosion prevention fluid?I have seen much smaller enclosed areas drilled and threaded for a plug and filled with oil to prevent rust and help locate any cracks in the future.IanMiller Syncrowave 200
Reply:No, we don't have the enclosed areas purged or filled with oil.The steel will quickly use all oxygen available inside and then the corrosion should stop.Inserting oil would leave an environmental risk especially above water.I know there are some large steel bridges which have nitrogen overpressure systems. Also in sections where air might ever intrude, bags of oxygen scavenger are inserted before closing/welding the hatches.
Reply:Originally Posted by ElGuapoNo, we don't have the enclosed areas purged or filled with oil.The steel will quickly use all oxygen available inside and then the corrosion should stop.Inserting oil would leave an environmental risk especially above water.I know there are some large steel bridges which have nitrogen overpressure systems. Also in sections where air might ever intrude, bags of oxygen scavenger are inserted before closing/welding the hatches.
Reply:Welds look awesome! Not something you see every day, very interesting.Miller Thunderbolt 225Millermatic 130 XPLincoln HD 100 Forney C-5bt Arc welderPlasma Cutter Gianteach Cut40ACent Machinery Bandsaw Cent Machinery 16Speed Drill PressChicago Electric 130amp tig/90 ArcHobart 190 Mig spoolgun ready
Reply:Those are welds??  Looks like someone smeared caulk in those joints...   wow
Reply:Originally Posted by ElGuapoAlso in sections where air might ever intrude, bags of oxygen scavenger are inserted before closing/welding the hatches.
Reply:by filled mig, do you mean flux core?  If so, what type?
Reply:Pressure changes due to oxygen consumption would be in the range of pressure changes caused by outside temperature rise & fall. Never heard of a closed beam, pipe or surface collapsing by that but it's an interesting point of view especially when stiffer sections are connected to large unsupported faces.Had some pipes collapsed by vacuum in a water pumping spread which started working as as syphon after startup though. Bending stress vacuum was too much for the thin walled 40".I'll have a look in the welding procedures about the filler this afternoon.
Reply:Here's the datasheet of the wire.http://www.nst.no/english/Datasheets...4%20271103.pdf
Reply:Here's the test results of the fillet welds of the stiffeners to the deck.The stiffeners are 6mm the deck is 12mm (upside down). The stiffeners are chamfered before welding. The weld is subject to fatigue because of traffic and needs a 4.5mm troath height. To check the penetration of the welding procedure a sample was made and tested destructively (cut, sanded and etched).Fillet welds are low in fatigue strength because of the initial crack.
Reply:That is really interesting, thanks for the pictures ElGuapo.Yup
Reply:is the dark spot  where the plates meet under the bead in the foto  a void??
Reply:yes.  not all that uncommon with fillet welded butt joints.   Originally Posted by weldbeadis the dark spot  where the plates meet under the bead in the foto  a void??
Reply:it surprises me that such a void is acceptable