January 2001 Back to Bridges back to Home page Links Building small bridges ought to be easier than building large ones, and of course it is. But it is not trivial. There are a few problems that would not occur on a large scale.
Scale is the clue.
As Galileo said, doubling the the length, width, and height of an object increases its area by a factor of four, and its volume and weight by a factor of eight. Whereas in very large suspension bridges the designer might be fighting for rigidity, in a model suspension bridge a big problem is making it flexible enough. Here are two principles that you can bear in mind. If you need to counteract a load using other forces, and these are at an angle to the load, these new forces will be bigger than if they were parallel to the load. If you apply a force at a distance from the force you need to counteract, you will need a bigger force than you would if you applied the force in the right place.