winter.  Here salt is being re-activated with every rain.  You see, it's not salt that is a catalyst for rapid corrosion, it's salt water.  Dry, the salt hurts little.  On the bridge, it is damp and dangerous nearly every day from the marine climate, rain storms, and nightly dews.

The pack rust here was so severe, it was literally spreading cross bolted beams apart by as much as an inch (25 mm).  The pressures created by such expansion are enormous. 

The pressure created by a rust expanded seam can even rip a bolt or rivet head off with explosive force, with a sound like a rifle shot.  We heard no loud bangs, but we did find a large rusted rivet with no head laying on the wide flange of the lower frameworks.  That it managed to lay there through repeated lifting and lowering is surprising.  It's also possible that it just popped free before we rowed under, and had only been there a short time.
Nonetheless, loose rivets laying around a bridge is seldom a good sign.

Newer repairs, such as the grey "sister" brace on the green vertical beam, are showing early signs of galvanic corrosion.  In this obviously recent repair, a metal piece with dozens of bolts is clamped over the old rusty girder. This use of dissimilar metal alloys exposed to months of salt mist is already taking its toll.  An ominously rusty crevice has been created by this "sistering".  Crevice corrosion can be very fast, and soon leads to the girder splitting forces of pack rust.

Months after the last salt spreader drove over the bridge, white stains are still clearly evident on the grey supports.  This salt residue is a great catalyst for galvanic corrosion, especially when damp--and it's almost always damp here.

Hopefully, the La Salle Causeway is not past effective or economical repair.  Although many would argue for a fixed bridge, repairing the bridge you've got is usually far cheaper than building a new one--in the short term. 

If inspection results in the de-rating of the bridge, crossing the harbour by car will be a nightmare.  De-rated bridges have a lane closed off, to cut the loads the structure gets.  To the motorist, it looks like a maintenance closure.  Frequently it is just a cheap way of complying with the inspector's order. Halving the capacity of this two lane bridge would need traffic lights at each end of the lane, only allowing traffic in one direction at a time.  Such lane closures often become permanent, as they cost nothing but the motorist's sanity.  Forget driving, walking would be quicker.


Of course, a shiny new elevated bridge is the preferred solution. It would eliminate those frequent summer waits as boats pass through.  Making it a four lane model would go a long way towards relieving the daily traffic congestion too.

But our Kingston Harbour without our one toothed jolly green giant just wouldn't be the same.