From a French Military Magazine I got a sketch from some Italian and German fortifications in Italy during WWII. I used one of these drawings to create a 3D drawing out of it. So I got a much better feeling for the structure and the dimensions of the obstacle.
Here one of the existing pictures showing the road blockage during the fighting. I believe it was The Luftwaffen Unit “Hermann Goering” who fought in this area.
While I searched the Internet for more information I found a very interesting blog, here you can find some other pictures.
So for me it looks like that these road blockages existed in several places with some smaller variations.
Some other pictures you can find on this Italian page: http://giuseppe-peluso.blogspot.com/2011/10/il-posto-di-blocco-costiero-di-arco.html
Here my 3D file for the road blockage: