Sometimes, things aren’t as they seem. At first glance while driving down the Riverside Parkway west of 5th Street, two of these recently erected power poles already appear to be bending under the weight of the high voltage power lines attached to them.

Since the poles and the lines attached are new, they should be straight like the other poles nearby, right? However, when seen from the Parkway, they appear to be bending. Is this just an optical illusion created by the way the poles are positioned and the power lines attached? Or, is there another explanation for the poles’ curvature?

Photo, Ed Chandler

Actually, the poles are designed to ‘bend’. According to Brad McCloud, Xcel Energy’s Area Manager, Community Relations Western Colorado, “the poles are ‘deflecting’ (not leaning) due to the tension of the wire. These poles are engineered with deflection tolerances so that they can be responsive to changes in tension.”

Designing Buildings Wiki defines Deflection – in engineering terms – as the degree to which an element of structure changes shape when a load is applied. The change may be a distance or an angle and can be either visible or invisible, depending on the load intensity, the shape of the component and the material from which it is made. Deflection is a crucial consideration in the design of a structure and failure to apply due attention to it can be catastrophic.

Deflection, (or bending as I like to think), of the power pole is good and the amount of it changes depending on the tension of the heavy power lines attached. As you drive by these poles, make a mental note of how much deflection there is and then on subsequent drives you can have fun trying to figure out if and how much that deflection changes.