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- เผยแพร่เมื่อ 6 ก.ย. 2024
- Perhaps more than any other area in the country, Washington state has a history of collapsing bridges. From the infamous Galloping Gertie and the Old I-90 bridge to the most recent Skagit bridge collapse, these "unintended field tests" have provided useful lessons for designers, contractors and engineers. Over 21% of Washington bridges are considered functionally obsolete and the average age of our nation's bridges is 42 years. As we look to the bridges of the future, what are the major technological breakthroughs that have led to dramatic shifts in design and construction? Join us and learn more about engineering the bridges of tomorrow.
John Stanton, Professor, UW Civil & Environmental Engineering
www.engr.washin...
10/30/2013
I had the honor of being in Dr. Stanton's courses in 2019 and 2020. He is so passionate about bridges, and a great instructor to boot!
This is a good comprehensive lecture covering most of the logical procedures that are used to build any type of bridge. I would say that the most important part of the lecture was the last part when the professor prioritise the requirements, starting with EDUCATION. Education in my opinion, should be conceptual and very practical and I do not see any harm, commencing at schools, if all children are given a screwdriver and all by themselves they would find in which direction one needs to rotate a screw to insert it, or withdraw it out. Such issues and logical procedures are not given any priority in schools and I just cannot remember how many people including may teachers and religious people, in and out of schools asked me, " Which way do I turn the screwdriver?" I am almost as old as the Tacoma Narrows bridge and every time I see the failure of that bridge, I simply cannot believe that in those days, they did not realise that the suspension bridge using a catenary curve combined with the vertical cables coming down to hold the deck, resulted in a lot of rectangles or rhombus WHICH IS A GEOMETRICAL SHAPE WHICH CAN CHANGE ITS SHAPE VERY EASILY as it has no diagonals. That bridge was full of rectangles or rhombus and so various modes of oscillations along the deck would be passed over to the flexible catenery and would distort the supporting rectangles /rhombus as the suspension system had no stiffness in the vertical plane not a bit, ALL DUE TO THOSE RECTANGLES formed by the catenery main cable coupled to the verticals and the deck itself.
I would say that when they felt the oscillations in 1937 , in four months time, they could easily have added a number of DIAGONAL cables starting from the top of the main towers/pylons and anchored them to the deck TO FORM TRIANGLES which is a shape that cannot change its shape. Well, all cable stayed bridge use triangles and trusses also use triangles long before the Tacoma bridge was built as the one I often visited in Scotland near Edinburgh ?ferry bridge. So again I just cannot understand why they did not incorporate TRIANGLES. So, it is logic and a full understanding of the silent and invisible static and dynamic functions in structures that one should have a feel for them. The universe is full of logic and so much natural engineering are around us, that even if one does not refer to any books, but simply take a lot of time to observe and question the natural functions around us. Structures are to be understood and I do have a smile when to have a dig at all artists, I tell them that " All art is based on an 'emotional engineering structure' and engineering logic" and that art without an observer in front of it, looking at it, resumes to being AN ENGINEERING STRUCTURE. That applies to music as well , where it is all case of permutating and combining in sequence certain engineering tones, or oscillations, which are harmonious, as if they are not........ what is emitted we call........NOISE. I would say that there is a mathematical law which has to be obeyed to differentiate music from noise! Having said that, all engineers should study the engineering side of what they design, but the outer lines and contours of any of their product, must be elegant and majestic in their nature. Nature did not do so bad in achieving it and so, it is no humiliation for any engineer to look at what nature did before us, including the little tiny spider which, speaking relatively to its size, it can bridge spans beyond what humans can even conceive.
The balanced cantilever technique was first used for a concrete bridge in Brazil and by the brazilian engineer Emilio Baumgart.
Great teacher with a great sense of humour
Awesome lecture! We have a thrust arch viaduct like that in the example shown at 19:05 in Wolverhampton on the Gorsebrook road and its amazing how they achieved that! On a side note, John Stanton's tie though .....We got a badass over here!
Comment about the large depth for the suspension bridge: Note that as the depth increase, the assumption of shear stress/strain not being part of the resistance becomes invalid and the shear resistance becomes more dominant (a timoshenko beam). The point of a beam is the depth is small compared to the span. Regardless, the point of the necessity to minimize materials is valid via bridges.
Thank you
great lecture
"This is a 106 AD so it's just had its 2000th birthday."
I want to know which bridges he did the math on, this information might save my life.
I’d like to hear what Prof. Stanton has to say about the FIU-Sweetwater (Fla) pedestrian bridge disaster.
I talked with him about that a bit. He told me that he and his graduate students did an investigation of their own to determine the cause before the NTSB released there results to compare.
Great insight
LECTURE WAS GREAT.........THANKS SIR!!!
LOVE FROM INDIA
The Macarthur Maze is in Oakland, not San Francisco.
53:40 sweet dreams
In my country India .that sense of proffeser is less
watching this after I got dropped from my engineering class lmao
1:05:10 gggggggg