Not that bad. It's just a regular basic bookshelf, as the BILLY from IKEA. They have to hold that, especially when they aren't not wider than here (it looks like the usual 80cm).
But paper is heavy, so a library's weight cn cause other problems. For the house for example. Too many full bookshelfs can be problematical, if they are in a lightweight house. No kidding.
And really ugly became books and magazines, when you have to carry them, for example, when you are moving. My tipp: use several small boxes, not the bigger moving-boxes. When they are full with paper, you cannot carry them.

If you have to move that stuff, look in the liquor stores or supermarkets. Ideal are boxes from sprits, for bigger stuff, as oversized magazines from the 60ies and 70ies, the boxes from champagner and sparkling wine. When they are full, you can carry them better.
But anyways: you are really groggy, when you have carried two dozens of cardboard boxes with books inside, than two bookshelfs or one refrigerator.