The Broken Cattle Guard

We received a call at about 2 PM on a Friday afternoon about a buckled cattle guard on a county road. The supervisor and I were in the office when we received the call and immediately went to look at the situation. Once on site, we found the cattle guard bent so we promptly closed the road. We noticed incriminating marks on the pipes and base material caused by the vehicle that apparently broke the cattle guard, but no one had witnessed the incident. Fortunately, there was a cattle gate next to the cattle guard that we were able to open and detour traffic around the damaged cattle guard.

We decided to remove the cattle guard, straighten it and put it back in place so we could open the road. We tried straightening the cattle guard by pushing down with the Gradall and backhoe on opposite ends, but we were unsuccessful. So, we flipped it over and we were able to straighten it by pounding it in the middle with the Gradall bucket. After seeing there were joints in the beams, we placed base material and bridge deck timbers under the center of the cattle guard to support them. We were able to open the road by 6 PM that evening.

The funniest part was that our backhoe was “brand spanking new”, right out of the box. We were unaware that the manufacturer had connected the hydraulic lines for the bucket backwards. When the operator used the controls to swing the bucket, it went out, and when he wanted it to move outward, it swung sideways. Our experienced operator was confused at first and had to use the new backhoe with this unusual configuration. We teased him about his operation saying we might need to drug test him. He did prove to us that he was having to change his normal mode of operating the controls to perform the work.

The crossing was constructed with railroad rail as the support beams for the traffic pipes. Whoever constructed the cattle guard placed a joint between two sections of rail for all the support beams at the center of the cattle guard (at the location of maximum bending which is not a great idea). We were fortunate the crossing did not need to carry drainage across the road since the ground sloped away on both sides of the road and we could place support under the beams. Our repair is carrying truck traffic, including logging operations, and performing well. When we get bored and have nothing else to do, we will pull it again and try to strengthen the joints in the beams by welding the two sections of rail together (and keep the interior support under the joints in the beams just in case).

Submitted by Bob Cochrane, P.E. (1-16-15)

Grimes County Engineer

P.O Box 2573
Cedar Park, TX 78630
Phone: 512-260-1376

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