Questions about building a gateway entry arch thing

[ning]

Our driveway has a couple ugly concrete pillars flanking the entry gate, and as part of a larger fencing job that I'm doing, I'd like to relocate our gate down the drive a bit to get more yard space, get a wider entry, and eliminate the ugly pillars.

In addition, I'd like to set up some sort of arch; for the purposes of this post assume it's like this -

though it's likely to look different, the basic questions I have are the same regardless of the style.

I'm going to make it so there's a good amount of clearance under it - enough for a big box truck or fire truck - though it won't have to fit a full-on semi (they won't come up the driveway anyhow) - still, it seems like 14' clearance is about right?

The question then - How to set up the pillars?
I see a couple options:
- massive pressure treated posts, dig deep and concrete them into the ground? (eg kinda like telephone poles)
- pour a footing and use brackets, use non-PT lumber offset off the ground just a bit to avoid rot with brackets - but are brackets enough to keep it vertical if the wind blows on it?

I figure brackets work fine for situtations where you have multiple posts (like 4 or more) and there's shear taken care of elsewhere, but most ranch entryways like this seem to have single verticals - also, where do you get a timber like that?

 

[Carl_NH]

Suggest doing telephone poles - you can find them used, cut them 20' long 4-5' in the ground minimum to allow 14'6" clearance. Then finish / side / box them with cedar or fir and put a top beam 8x10 x 16' and trim it out as you want - to create an arch or what ever you want design wise.

 

[boomer1025]

Minimum clearance 15+ foot

 

[bcp]

Set the gate back far enough that a tow vehicle and long trailer can easily make the turn, and stop totally off of the road to open the gate.

Bruce

 

[Doughknob]

The question then - How to set up the pillars?
I see a couple options:
- massive pressure treated posts, dig deep and concrete them into the ground? (eg kinda like telephone poles)t poles not cemented. At least not here. Planted deep enough, and fill dirt tamped in, then the cross bar on top will hold you in a tornado.

- also, where do you get a timber like that?any good lumber yard. Big box stores r not lumber yards….

j

 

[Hoodoo]

Plant 'em deep. Check the span tables, but to span 12 feet, you'd roughly want a 12 inch thick pole or beam. I would set them in concrete if it were me. Use tar for the underground portion of the wood pole...

 

[Jims1025R]

If you are planting large poles in a part of the country where the ground could freeze for weeks on end (more than just a few frosts), bury at least 2" thick foam insulation tight around the poles, to about two feet radius out. Bury it 2"-3" below ground at the post, sloping away so any water soaking into the ground will not run toward the post. This will reduce the chances that the ground will freeze around the post, and then heave, picking the post up, and soil filling in under the post, so it cannot return back down in the spring. I learned this trick the hard way, after water running around the posts of my former pole barn froze, and heaved the poles, so my roof was no longer level. Once I dug and insulated, problem solved for the next twenty years!

 

[oosik]

As I drive around this part of our state - I see a few gateway arches. Most are massive pine pillars with an even larger cross member on top. I've never witnessed one being built but I would guess the pillars are sunk PLENTY deep. We do get frost down to four feet and deeper here.

They have all been finished with something( varnish, lacquer, etc) and look pretty shiny.

I wonder if this display of grandiosity would attract thieves. I've never been inclined to do something like this. Besides - look down my driveway - past my outer gate - this time of year. You will see my "muddy section". The grandiosity of an arch is lost in the world of reality.

 

[RalphVa]

I agree with the minimum clearance of 15 feet for any trucks delivering or picking up stuff.