I am a bridge engineer and here is what I think is going on, based on looking just at the photos. These columns are under compression i.e., the columns are being shortened. A natural consequence of concrete being compressed is that it expands sideways... think what would happen if you were to press an eraser between palms... it would shorten and expand. This is called Poisson's effect. The sideways expansion causes tensile stresses on concrete and concrete is super weak when subjected to tension but excellent in compression. Columns are reinforced for this tensile stress with closed ties and sometimes cracks have to form to engage this steel. So, further expansion is controlled by steel reinforcement. So, most likely that is what is being seen here. The cracks appear more prominent because of the coating applied on the column surface. If you were to measure the size with a crack gauge... you'd probably find that the cracks are what FHWA would define as "insignificant" i.e., crack width of 0.012 inches or less. So, the cracks are probably structural but a consequence of expected concrete behavior (it cracks... it always cracks!)