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3 Pin Arch

3 Pin Arch

3 Pin Arch

(OP)
I'm looking at some 'pins' for a 3 Pin arch assembly with reactions of approx 100K to 150K and was going to fab them out of steel and hotdip the assemblies. Any suggestions on oversizing the pins for coating? Also any bearing issues with the zinc coating 'crushing' Including the crown pin, there would be approx 240 assemblies. I don't know what they do for bridges. Maintenance will likely be sporatic. The environment is relatively dry with some airborne potash and the life expectancy is approx 50 years. The main members are likely glulam. Any suggestions on alternatives for the bearings? What would they normally do for bridges?

Dik

RE: 3 Pin Arch

dik....the zinc coating will gall if bearing on steel, so you will likely get removal of the coating at some point. If your bearing is on Glulam, I wouldn't worry too much about it galling.

As for thickness, consider using a G90 coating (0.90 oz/sf) at least.

RE: 3 Pin Arch

(OP)
I don't know what happened to my reply... I thought about the condition and even though I don't anticipate much rotation, I think I will use a stainless steel pin and bushings and avoid the HDG issue. Thanks, Ron.

Dik

RE: 3 Pin Arch

Dik:
I think stainless on stainless will gall also. With that quantity you might consider chrome plating the pins. I assume the connection is a single center plate on one member, with two side plates on the other member. Put a simple bushing in the center pl. and just leave the two side pls. bored for the pin and a locking means. I wouldn’t expect much rotation, I think you will primarily just get a change in the direction of the shear force on the pin and pates.

RE: 3 Pin Arch

(OP)
Thanks dhengr...

Dik

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