ABOUT STRUCTURAL DESIGN: All modern high-rise buildings and most bridges feature something called redundant design: when one section fails, the entire structure should still be able to stand. It's a bit like a net: lose one string and the net will be weakened, but as a whole, the net still functions. Most high-rise buildings and bridges also are designed to sway in the breeze, because if the structure is too rigid it can snap under too large an impact. The World Trade Center was designed to withstand strong winds striking it from the side, and was even able to absorb the initial impact of an airplane colliding with it on 9/11, although the Twin Towers ultimately collapsed
Fiberglass is a composite material. A composite is any material made of more than one component, and therefore has properties of both. Glass fibers are embedded in certain polymers to make them stronger. Fiber-reinforced composites are both strong and light, often stronger than steel. Fiberglass is one such composite. In fiberglass, the glass fibers aren't arranged in any particular direction. By lining them all up in the same direction, scientists can make the composite stronger -- but only in that one direction.
A Bridge with Skin? That's an example of biomimicry, a field in which scientists, engineers, and even architects study models and concepts found in nature, and try to use them to design new technologies.