Here's a little change of pace. A local business purchased 34 feet of modular cattle guard, rented a backhoe, and had their guys try to put it in. After three days they got two 12 foot sections in, but they were 8 inches out of level and out of square too. There were several factors that led to the problems the guys were having. First, they tried to set the footers on black clay. And not their fault...but they were using a string level not realizing that the footers were slightly off on the top to bottom, side to side and bolt center measurements. To top it off...a couple of the footers were bulged in the middle. The grates had plenty of end to end adjustment built into them, but only 1/4 inch of play side to side. With the help of my stepson, we pulled the steel grates off, ranked out the footers and started over.
This area has plenty of black clay, but you'll find a yellowish rocky clay down a few feet that's a lot more stable. I found it only a couple of inches below the depth they had excavated on one end, but had to dig it down about five feet on the other end. Once I had the bottom of the trench packed in with a couple of feet of yellow clay, I placed 18 inches of 3/4-minus utility rock, set the grade and the first two footers.
W used a combination of the laser, string line and a healthy helping of good old "eyeball installed" to get everything set and lined up. Of course, we put the 10 footer between the 12's to make things look right.
I'll go out tomorrow to grade out the overburden. At some point in the future we'll get more gravel or sand in the center to fill it up a bit.
