A Bespoke Over Arch Bridge Build

[shropshire lad]

One of my first attempts at infrastructure is looking a little tired and now has a point at one end so thoughts of it's replacement surfaced. Whilst considering the best way to broach the subject with my tame(ish) welder he helped me out by breaking his laptop. After a site visit to collect his repaired laptop he 'volunteered' to help.
The bridge to be replaced

Big plans

Andy the me(n)tal bridge builder forming the arches

The arches awaiting finishing,drilling for lights etc. Hope the radius is right

 

[minimans]

Is that CNC bender?..................................Love those old machines

 

[KeithT]

That's a h**l of a track bender!
There seems to be a rash of bridges at the mo'.

 

[Philbahn]

Like the scratchh my back & I'll scratch your approach Colin. Thats the way I got mine
Hope you're going to get it powder coated as well

 

[shropshire lad]

It's certainly going to get a coating Phil, still looking at some options tho.
As it sits over a pond rust proofing is essential.

 

[Philbahn]

Galvanised?

 

[shropshire lad]

I've been looking at a thin galvanising coating which is formulated to take paint. It's used on wagon bodies etc. It would give me the option to change the colour if needed

 

[trammayo]

Wish I had a tame fabricator! You can use T Wash to allow you to use paint on galvanised or let it weather for a few years!

 

[beavercreek]

Looking a goodly start Colin...you can always use the old bridge as a hammock!

Could you use industrial anti rust paint to seal it first?

 

[jameshilton]

Colin I think you'd find the middle of the bridge would probably have a cross or braces rather than none - although you may have this in mind, as I don't know how much of a finished job your design sketch is? Looks like it'll be a nice custom job

 

[shropshire lad]

We looked at centre bracing James but it just didn't look right. There's not much space for cross bracing without emphasising how short the bridge is compared to the arch. Obviously it may look different when built!!

 

[Richie]

Now thats the way to build a bridge Great work Colin look forward to the finished structure

 

[shropshire lad]

Thanks for your comments guys.
The basic bridge was laid out to check it looked ok and to spot any major problems

The only obvious flaw is that it takes two dodgy geezers to hold it together

 

[mike]

well the one in the bright floresasnces jackets well dodggy

 

[shropshire lad]

Cheers Mike,it's an underated talent

 

[beavercreek]

Isn't that Isambard Kingdom Brunel, in a natty little flourescent number, working on one of his first bridge designs?

 

[shropshire lad]

Now wheres me stovepipe hat?

 

[beavercreek]

Failing the Stove pipe one how about a smoke stack jobbie........

Your bridge is looking superb Colin

 

[yb281]

Isn't that Isambard Kingdom Brunel, in a natty little flourescent number, working on one of his first bridge designs?

More like Eddie Izzard Brunel?

 

[minimans]

Colin might I suggest that the vertical and diagonal links be done in a smaller diameter square tube say 1/4 in if your main beams are 1/2? I think it would look a bit less shall we say over-engineered? and detract less from the trains as they pass over? but still a damn fine impressive bridge all the same!

PS I like the middle picture of the river bridge, you could use stainless rod to represent the braces, so no worry about rust! If you powder coat make sure you close up the open tube ends with a welded plate beforehand or it will rust from the inside out. Trust me I know on this one.......................................