Driveway Entrance ?

[happyj]

Quick thoughts on entryway plan.
I was wondering what anyone thought about using an 8"x8" timber when spanning this distance? it is 18' from post to post.
Will i need the bottom braces to secure it appropriatly? Or can i just use some kind of metal tie from the masonry kneewall/foundation.
What about the size i will want to get a truck and trailer through it so i made it pretty wide. I also need to bring in dump trucks occasionally so i made it 14" high. will that be enough?

Thanks in advance

[Tom]

I have to pass through gates that the homeowner thought were too wide and I would have trouble.   A big truck, with large mirrors, is wider than his bed.   The bed on trucks in our area is limited to 8 feet.  I find that it fills up a 12 foot drive.  One must also consider the turning radius of trucks and trucks with trailers.  If the entrance is close to a road and necessitates a 90 degree turn off of a busy road, it must be very wide to allow for the "swing" of a trailer.  Eighteen feet wide begins to be a minimum for gates and culverts as well.

An entrance way that limits height of load should be no less than the legal height allowed for trucks in your area.  Trucks in my area are limited to thirteen 13' 6" in height, including load.  Your fourteen foot clearance would allow a legal load by 6".   It might not allow a truck loaded with some heavy equipment to pass.

A truck driver will appreciate a 30 foot wide exit from the road to your property and an opportunity to straighten out before  he has to pass through a gate (the eye of a needle).

If you are talking about a 8x8 for a cap on top of 14' poles, it should hold itself up.  I would lean toward a couple of 2x8's with 2x4 spacers in between just to cut down on the weight.  It would still look fairly massive.

[happyj]

Thanks Tom

I have another entrance to bring in the bigger loads this is just for the occasional gravel load for the driveway going up to the house. So there is plenty of room to back in and i live a couple of miles from a paved road so no traffic to speak of. There is plenty of room to get squared up before the entryway so is 18' plenty once straightened out?
How would i do the joinery if i did it with 2x8's w/ 2x4 spacers? I understand it would look similar but would i just leave out the spacer and center up the tenon on the post?

[Tom]

Eighteen feet would probably get it done.

Yes you could center up the tennon on top.  I was thinking of the weight of handling an eight by eight as well as it's haveing to hold its own weight for years.  The 2x4's would be nothing but stiffeners and would hold the 2x8's apart the same distance as the tennon for the full length.

There is nothing wrong with the 8x8 accept for having all that weight to put up there and then having it over your head all the time.

[happyj]

I understand

I was going to stand it up as a finished bent with the tractor. I had not thought of all the wieght up there until you mentioned it though. I was intending to carve a sign and hang it from chains as well so there is more wieght. I wonder if i should take up up smithing?  :P 

[Tom]

Smithing is a good trade.  I don't think we have a smithey on here yet. 

Yes we do!!  what am I thinking.  Ernie_Edwards wife, Darla, is a champion blacksmith and has showed some of her wares here on the forum.

[beenthere]

 happyj,
Hanging a sign will lower the clearance.
An 18' 8x8 will probably develop some swayback after a short time, which may or may not be the effect you want.  If the ranch is going to be called 'straight arrow' or something like that, then a swayback beam may not cut it.    Now if it is 'valley ranch', that may fit right in.

[happyj]

How big to not sway would you reccomend? I figured i would have the sign on chains and would remove for clearance when i needed. should only be once every few years. If it becomes to much trouble i can just have them dump the gravel and i can spead it myself.

Thanks for all the thoughts i really appreciate them.

[Raphael]

  Generally making a beam 2" or more deeper than it is wide will negate the tendancy to sag...  But that's just a rule of thumb, it assumes the beam has been sized for a structural load and the beam is placed crown up.
  A lot depends on wood species, but I'd guess an 8 x 10 shouldn't sag on you.  If you made a composite 8x10 from graded lumber in the way Tom suggests there should be no problem.

[happyj]

Thanks i will look at upsizing or making the composite beam as ya'll reccomend. I will keep it posted. I hope to attempt to cut the timbers next weekend. I might change it and make it a regular bent with and roof on it.

Love reading what everyone is doing and i really appreciate the assistance.
;D

[Raphael]

  If you do raise this as an assembled bent I'd strongly suggest adding some temporary bracing to the top corners corners at the very least.  You want to keep those joints from flexing.  I've raised two this way... three if you count the one that got damaged on my first attempt (no bracing).  :(
  I've also done several the other way when we had enough crew to do it 'safely'...  I don't thing OSHA would approve of the lack of hard hats or the old wooden step ladders; sometimes you have to use what the boss provides.  :
  You've got to be really careful working with heavy timbers overhead, a friend just caught a beam with his skull and fell with it from the 11' step on a ladder.

  I need to get the whole story and a picture for the safety forum before his hair comes back in.  I know the beam was in place and he wasn't looking at it when it fell.  He was brought into the VA and we had to ship him out to a nearby hospital for surgery, they relieved pressure from three hematomas and stitched his scalp back together.

[Don P]

 Depending on the sign, the load here is so small I don't think it'll matter much. Independent of the thought process, I'm seeing a narrow roofed spaced 2 ply beam.  Your sign isn't a tractor or anything is it  ???  ;D

If you all don't mind too much, this is a little different beam than usual.
The beam has no lateral support. Usually a floor or roof restrains the top edge of the beam from buckling. If the load gets serious (think engine hoist maybe), and if there is nothing restraining the top edge of the beam in the span, then the beam wants to twist.

Nailing two or more plies together is not the same as having a solid beam in that case. It has less "torsional rigidity". In fact engineers only allow one ply in their beam stability check for this situation. The judgement is that yes the other plies contribute but how much is very variable. If the beam gets too unstable for one ply to handle the twisting stress, its time to consider a thicker ply or single thick beam.

Another place this is likely to creep up and cause trouble is in a dropped header with a short kneewall standing on top of it over a large opening, like a garage door or sawshed might have.

[Tom]

The neat thing about building a beam for the entrance is that it can incorporate bat houses on the underside and nesting for birds on the top,   While you might not find it desirable, it would certainly be an interesting experiment.

[happyj]

Nope i hope my tractor does not end up there.

Narrow roofed spaced two ply beam? Do you mean the 2x8's sandwiched with a 2x4?

I am reconsidering if i should put up two bents and put a metal roof on it now. I need the practice anyway.

have a great day

gonna saw some this weekend !!!!!!!!!!