BRIDGES their engineering and planning
Roads hug the earth’s surface. Pipelines and tunnels burrow under- neath it. But bridges soar through the air, without ever really leaving the ground. On beholders they make a distinct impression. Unlike buildings, which are more numerous but clad with outer surfaces that usually keep the underlying structure hidden, bridges reveal the structural principles that keep them aloft.
They are the most visible expressions of engineering as art, or of architecture as science. Some are gateways to regions, symbols for entire cities, and world-renowned monuments in their own right. Some bridges, like some violin concertos, have magnificence that cannot be expressed in words.
While many kinds of human contrivances mar the natural landscape, bridges—even ones that are not particularly famous—are likely to complement it. They provide sequentially shifting panoramas for those crossing them, dramatic objects for those observing them from a shore or embankment, and framed horizons for those looking through or past them.
Bridges as structural art are to be appreciated in their own right, but also as environmental art: pieces of artifice that enhance awareness not just of the artwork itself but also of the hills, chasms, torrents, skylines, or forests among which they are situated.
Before they can be art, they are economic infrastructure. They are essential because we move around on the earth and the earth’s surface is, fortunately, not a flat and solid expanse. It has gullies, rivers, valleys, hills, swamps, crags, coves, and cliffs that must be crossed if we’re to get about. Since we build roads and railways, it is often also wise to make them leap over each other instead of intersecting.
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