附註:Preliminaries -- Contents -- Preface -- Some Basics -- Forces and Elasticity -- Stiffness and Strength -- Kinds of bridges -- Bending -- Ties -- Struts -- Beam bridges -- Arch Bridges -- Suspension Bridges -- Pontoon bridges -- Materials -- Appendix -- Glossary.
摘要:The aim of the Watching series is to draw attention to some of the very interesting items around us, things that perhaps we don't notice as much as we might. The first was Bridge Watching, and when this was put "on the Net" it produced, to the surprise of the author, such a pleasant flood of e-mail that another was written, called Water Watching. This, too, was kindly received. So it was tempting to continue with the theme. Wherever we go we seem to meet bridges. Mostly we tend to use them almost without noticing them, except when we see a particularly striking example like the suspension bridge over the river Tamar in Devon. There is no attempt to cover everything about bridges, just enough to make a bridge a more interesting object for you, or your camera, or your paint-box. I do hope it will help you to enjoy bridges, wherever you see them. They are such nice comfortable things to watch, especially when you know something about them. As either a hobby or an intellectual pursuit bridge-watching has much to commend it, for people of all ages and persuasions. You don't have to pay a subscription. You can enjoy it on your own or in company, and weather is relatively unimportant. It doesn't need any special clothing or equipment. (If you like, you can use field glasses or cameras, and note-books; but they aren't essential). You need no training, no practice, no coaching. From all angles, bridge-watching is an attractive pastime, all over the world. Go out and enjoy these fascinating structures. You may find them addictive, in the nicest possible way.
