Designs B/C

[Jim_R]

Discussion for Bridge designs or construction methods.

[thsom]

Will there be a wiki for bridge building itself? There is one for elevated bridge (the bridge building one redirects there), but it's not very specific IMO. Bridge building is not my forte, my strengths lie greater with towers and boomilever.

[embokim]

Well if you think about it a bridge is two boomilevers put together.

[Rath4o1]

If you were to take a sheet of Bass wood and have it curve into a half pipe like shape with notches cut into the top where the loading block may rest how would that hold up against a typical square bridge?

[JonB]

If you were to take a sheet of Bass wood and have it curve into a half pipe like shape with notches cut into the top where the loading block may rest how would that hold up against a typical square bridge?

It would be very heavy if it were a sheet of bass wood.

[iwonder]

If you were to take a sheet of Bass wood and have it curve into a half pipe like shape with notches cut into the top where the loading block may rest how would that hold up against a typical square bridge?

Probably not as well as you might think. So, assuming you have the open side facing down, and you brace that with more wood so it doesn't fold open, where your loading block is resting will be a stress concentration on the wood. (All the load from block is concentrated on two small (very, very small actually) surfaces where the notches are cut. In a normal bridge, those members span the length of the structure and they're what's braces from failure so it's no big deal. It a half pipe design, the end of the notch has to somehow spread the load to the entire half-pipe, which doesn't happen very nicely since it's a sharp angle, and causes the wood to tend to break in that point.

(There's actual pictures and better descriptions in the boomilever thread from two years ago, when we talked about tubular boomilevers)

To be honest, you'd have to try it and find out, but that's just kinda my first impression of it.

(Also if anyone wants help on the math or technical data of this kind of event I forgot how much stuff we used to discuss in the 2013 archives it's all for boomilever but it's still applicable...)

[bearasmith]

Unfortunately we can't use the upside down arch bridge, because of rules. But how do you think an elliptical arch bridge would do? Or do you think it would be safer just to use the cube bridge?

Thanks,
Bearasmith

[dholdgreve]

What say you Bridge Builders? Should the Loading Block sit on top the bridge, bearing on the top chords, or sit in the bridge, bearing on the bottom chords?

[iwonder]

I say you'll have to try and find out.

[chinesesushi]

What say you Bridge Builders? Should the Loading Block sit on top the bridge, bearing on the top chords, or sit in the bridge, bearing on the bottom chords?

I say that both have potential and depends on the builder not the design Also what iwonder said