See things clearly
“So how does that bridge work?”
A few years ago, one summer evening I was with my son and daughter, wandering the shore of the River Forth, the majestic road and rail bridges towering over us.
“The curvy one”“The road bridge, that's a suspension bridge. The four big posts hold up the cables that make the curves, and those cables are tied to each side of the river. Strong metal ropes hang from the cables and hold up the road, so we can drive across safely. It’s simple, isn’t it?”
“Yes....How does the other bridge work?”
“The rail bridge, is a cantilever bridge. It’s a bit more tricky to explain. Tell you what, take a look at this old photograph on my phone.
After a very long day, I was happy to leave an explanation of trusses and suspended spans, and tension and compression forces, to another time.
It’s always handy to have the simple ‘big picture’ of complex things, when trying to explain clearly how they work.
(Attributions: Road Bridge - Ross Imlach; Forth Bridge - William Starkey)
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