Another Bridge Thread

[LD1]

Cedar is not a huge difference from SYP. Problem is grading. How do you grade a "self cut" live log?

Here is a good calculator Maximum Span Calculator for Wood Joists and Rafters

Grade for grade, SYP dont offer much more strength than cedar. It is slightly stronger. But not much. But whats the grade of the logs?

I like steel. Predictable properties, easy to calculate. And cheap if you are patient and shop the used market. Steel is steel, uniform and consistent. Wood is alot of unknown as a tree/log/board is or was a live growing thing. could have defects that could make or break a load bearing bridge.

 

[Tractor Seabee]

I built a 10 X 16 bridge using RR ties. Excavated a trench each side of the creek down to bearing material, filled with crushed gravel and set two ties on top and filled around with more crushed gravel. Three RR Tie stringers across the creek anchored to the sill ties with 2' long steel form stakes. Decked with rough sawn fir planks full 2" thick anchored to the stringers with 9" long nails. I t is going to be there a long time. Drive my Dodge 3500 dually with two yards of gravel over it with no deflection. Food for thought. I figured the cost was around $500.

Ron

 

[Luke'sScreenName]

Ive never seen 16' RR tie! Where'd you get them?

 

[Tractor Seabee]

Ive never seen 16' RR tie! Where'd you get them?

16 footers are what are called switch ties. Used to support switch assemblies. We have a railroad salvage company here that buy up used ties, rails, accessories and machinery from RR improvement/repair projects. They sell ties that are originally 9-16 feet long and several cross section dimensions. They have a huge chop saw and will cut to any dimension. They custom package assemblies for landscaping for contractors and homeowners. Their prices on the standard 9 footers for a #1 is 30% less than the lumber yards, landscape suppliers and big box stores. Those outfits do not stock them as the average DIY users cannot haul or handle them.

I build a lot of things using ties. They make great foundations for tents and sheds as example. My flimsy HF greenhouse sets on ties. I have them as the base for two enclosed garage tents.

Ron

 

[Luke'sScreenName]

Yup, one of my Rhino Shelter 'garages' sits on RR ties. A very useful resource.

 

[tennesseejb]

Looking into switch ties. Still leaning toward the PT lumber, if only because it feels more predictable. Did find these though...

i-beams

Assuming I don't have access to a welder, how would you tie the beams together (like blocking the wood beams)?