The Art of Structural Engineering: Bridges | PrincetonX on edX | Course About Video

Take this course for free on edX: www.edx.org/course/the-art-of...
About this course
In this engineering course you will learn how to analyze bridges from three perspectives:
Efficiency = calculations of forces/stresses
Economy = evaluation of societal context and cost
Elegance = form/appearance based on engineering principles, not decoration
With a focus on some significant bridges built since the industrial revolution, the course illustrates how engineering is a creative discipline and can become art. We also show the influence of the economic and social context in bridge design and the interplay between forces and form.
This is the first of three courses on the Art of Structural Engineering, each of which are independent of each other. The two other courses will be on tall buildings/towers and vaults.

[@JudgeFredd]

Fascinating subject

[@carmelpule6954]

It is such a pity that the elegance of the old catenary suspension bridges have an inherent stability if the deck is not solid enough, The Tacoma narrow bridge went into an oscillation because the vertical suspension wires from the catenary holding the deck did not contain a single triangle and so due to its length the deck started flexing and oscillating. If one examines the catenary bridge as in 0:.49 the only triangular form is obtained by the considering the attachment of the catenary at the centre of the bridge. This centre point is reasonable stable and so the fundamental mode half wavelength cannot be supported. The full wavelength can be supported however and this is the mode that was excited at the Narrow Tacoma Bridge. If the designers added another thinner cable running from the top of the tower to one quarter of the length of the bridge, the full wavelength mode would have been eliminated and using two more triangles the higher modes would be eliminated too. The very higher mode would have not been possible due to the solidity of the deck structure over a short length.
Another manner to stabilize the catenary bridge is to run cables from the junction of where the deck meets the tower and go upwards towards the catenary thick cable to meet it somewhere about one quarter length of the bridge from the tower. This would not permit the thick cable to swing up. A few more cables from the mentioned junction running upwards to stabilise the first few modes of oscillation of the catenary curve itself would have saved the day at the Tacoma Bridge. I would even go as far a s saying that they had plenty of time to do it as the vibration was noticed about one month before it fell, and one month was long enough to brace the catenary curve down to eliminate the harmonic that destroyed it.

[@kapornith]

Hi, The URL seems not to be working. Neither does it shows in any of the upcoming courses.

[@edXOnline]

+kapil sharma Try it again - the link is active.