I am building a cable fence along an approximately 370' foot bluff, which if the cable runs were linear would not be much of a problem. Though, due to the irregular topography of the bluff edge my cable runs will not be linear (see attached picture). My question is, will my intermediate posts, 2'x2'x.25' T'ed angle iron, be able to handle the horizontal load of the tight cables? To be honest, I not even sure that I have all of the numbers data to figure this out, but I'm hoping that you all can walk me through it. Here it goes!
To start, the 370' feet of fence is broken into three sections, each approximately 90' in length. Each fence section will have seven strands of cable 4" apart (I should not here that we are not building this fit any codes, since it is being installed on our own volition. This means that we are not worried about things like horizontal deflection of the cables). Each section, or run, will be anchored to a 4" thick walled pipe by tension devices to bring the cable taught after it is initially attached - these are essentially turn buckles.
The cable is a .25" galvanized aircraft cable that is coated to 5/16 in nylon. Here is where I might be missing some numbers. Do I need to figure out the weight of the cable and how tight, or how many lbs of tension will be placed on each cable? I also might need to give you all the angles at which the intermediate posts will be offset from the center of the linear path between main posts - though my drawing is somewhat to scale and can give you an idea of the offset angles.
Let me explain the posts further. Each 4" thick walled pipe (hereafter referred to as a main pipe) will be placed into a 5" hole drilled 1' deep in white sand stone, then surrounded in quickcrete. The method is similar for the 2'x2'x.25' T'ed angle iron, though they will be placed and cemented into a 3' hole. In recap, their are four main posts - one every 90'. We will be spacing the intermediate posts, the 2'x2'x.25' T'ed angle iron at 10' foot intervals.
And here is where my question comes: will these intermediate posts be able to hold the horizontal tension of the seven strands of cable that are pulling through them? Should I add a 30 degree tie down to the back of posts to help with some of that deflection?
Ok, that is what I have for you right off the bat. Please let me know if - which is probable - so. what additional information is needed. And, please, enjoy!