The Extruded Cable-Stayed Footbridge!

This pedestrian bridge was an amazing opportunity to learn not just about various structural systems and materials but also how to collaborate on a project where both the architecture and structure are one and the same! So I use this project to explain the structural behavior and design approach for you.
I also reference my KZbin video on trusses, columns, and beams which can be found here:
Trusses: • How Trusses Work! (Str...
Columns: • How Columns Work! (Par...
Beams: • How Beams Work! (Part ...
Project Credits for Lockmeadow Footbridge:
Client: Maidstone Borough Council
Structural Engineer: Flint & Neill Partnership (now part of COWI)
Architect: Chris Wilkinson Architects (now WilknsonEyre Architects)
Contractors: Christiani & Nielsen, D&B Darke, Nedal Aluminium

[@karoma7898]

gongrajulashens! you're one of the many architectural engineers who went to make great and interesting things, which isn't a given where i live, usually you end up doing everyday homes and paperwork for developers, and answering some boring things like "can my house, made of plastic straws and toothpicks handle the weight of an 8 cubic meter indoor pool?" ... anyway, it helps to know how to spell congrajulashens :)

[@ericroberson8474]

I'm so glad you shared this, Paul. Your work and educational materials are so interesting to me.

[@PaulKassabian]

Thanks and you're welcome!

[@errishavsingh3767]

@@PaulKassabian Hi sir this side Rishav from India and i am learning basic concepts of Bridge.... please help me to khow more as i am new here

[@FoxRiverBridge]

"So I don't hurt its feelings" earned my like

[@PaulKassabian]

Liked back...

[@clintonchijioke330]

great to learn from you Sir

[@TomTurner704]

Far from being “Woody Allen's ugly brother,” I find you articulate, personable, witty and attractive… a person one would like to hang out with. You are one of the best “explainers” on KZbin, and definitely the best explainer of structural principles. I like this bridge. Might it be called a “boom” bridge? The structural layout reminds me of how we would pull tree stumps, or fence posts, out of the ground. You tie a chain onto the stump/post and then up through a V notch in the end of a post propped up at about a 45-degree angle and then connected either to a tractor or a good strong come-along puller to the base of an adjacent tree. It converts pulling force to uplifting force. Isn't the load on the pedestrian bridge greatest, not simply when it is full of people, but when it's full of people and someone plays music causing the people to move rhythmically. If the song's rhythm happens to match the natural frequency of the bridge... that's when things can really go wrong. Whenever I find a cable pedestrian bridge, usually on hiking trails, I pace out to the center point and bounce up and down at different frequencies until I find the natural frequency of the cables. The up and down movement can become quite amplified, sort-of like “Gallopin Gertie” The Tacoma Narrows bridge collapse.

[@PaulKassabian]

Thanks! And great point about dynamic crowd effects on structures with positive feedback. I think the most dangerous is when there is some rhythmic external source (e.g. music etc.) that keeps a large crowd, that would typically be disorganized, in sync with each other. This is sometimes seen at crowded stadia...see first few seconds of this for example! kzbin.info/www/bejne/h2a3cqWGmrN1bNE

[@Misterrocha]

I'm an strcutural engineer myself way down here in Brazil and your videos are amazing! It is great to get to know your work! Thanks a lot for sharing it!

[@PaulKassabian]

Thank you very much!

[@HeJurm]

Thanks for the new video!

[@TRON0314]

HE IS BACK! 👏

[@osamakhaled8169]

thanks for sharing i am learning a lot from your videos

[@PaulKassabian]

Glad to hear it!

[@abdullahadel9716]

Thanks.

[@speedbird7587]

really nice and impressive

[@PaulKassabian]

Glad you like it!

[@oneperspective8601]

I am so jealous Paul. It’s very challenging finding a structural intern position right now and seeing your videos makes harder to wait. I’ve had a dream of working on buildings and very architectural bridges

[@PaulKassabian]

Thanks for that...it's interesting because technical ability is the necessary part of being a structural engineer of course but real enthusiasm for your own work is what will keep you growing! Good luck!

[@pavanchandan701]

Awesome video. Filled with so much knowledge. Thank you very much sir for sharing your knowledge 🙏🙏

[@PaulKassabian]

You're welcome!

[@KF1]

Neat bridge, man!

[@anouch14]

I love your video. Thanks for sharing - and great to see you virtually !! Been too long, Paul.

[@PaulKassabian]

Thanks Aud! Way to long...reunion when we're next in the same country?

[@shingoeverard6744]

that was very interesting! Thank you for the presentation!

[@PaulKassabian]

You're welcome!

[@jwdory]

Graeat video!

[@franko8572]

Dang, I’m so early! 21 seconds! Here we go, boys and girls! P.S. Thanks for the upload!

[@PaulKassabian]

You're welcome!

[@puridade1]

learning a lot with your videos !

[@PaulKassabian]

Glad to hear it!

[@olson.pamela]

I hope you have since met some smart women that clued you into the fact that you are handsome! Your intelligence and obvious kindness are very attractive qualities.

[@hedaytullahkarimi1976]

I am from afghanistan and i appreciate your work and intelligence and i am big fan of you if you react to this i will be happy And how do you study your methods?

[@PaulKassabian]

Thank you...I have been a practicing structural engineer for >20 years and I also taught at MIT for 9 years and then at Harvard...so the videos are a combination of my project and teaching experiences!

[@woodennecktie]

nice solution to the resonation problem , altough weight is good against oscilation , weight is also your biggest problem , the dampers in the strings handle the longer waves. pity the design turned out less attractive from the blueprints

[@mrbigcat9]

Worse load case runners covering every inch of the bridge running at a very high pace?

[@wesleyc.4937]

YOU MEAN TO TELL ME ---- It's low maintenance AND it carries a load too?

[@realsabab]

its a part of upcoming RTX 5090

[@Sammyismysidekick]

Thank you for service and impressive work

[@MikeAG333]

Aluminium, because we're right, and they're wrong. The clue is in the name of the language.😄😄 It would have been nice to see a section through the steps, because it is difficult to picture what you are talking about with the cantilever, and with the slipping elements tied together. 'twere it me (I'm an architect), I would be a bit disappointed with the big clunky lump of concrete that the steps climb. With a slim and elegant overall design I found that a bit brutal and intrusive. Even a good planting scheme to hide it would have helped. Ivy to the rescue! Your tower and its diagramatic explanation reminded me of the bridge I built to win a competition at university many years ago.....the lightest balsa bridge to span a 2 metre gap. I did it by putting the structure into compression along its length using dental floss to carry the 3kg load. It still holds the record, apparently.