Every Bridge For Every Situation, Explained By an Engineer | A World of Difference | WIRED

Dr. Nehemiah Mabry, PE, knows a lot about bridges. Nehemiah is a structural engineer and an educator; and he builds bridges for a living. Dr. Mabry sits down with WIRED to talk about all different kinds of bridges from around the globe. What's the difference between a cable-stayed bridge and a suspension bridge? Are bridges in China different from bridges in the United States? Why do they decide to build one bridge over another type of bridge?
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[@TehBurek]

Not to sound repetitive or anything... but whoever was in charge of lighting here shouldn't be allowed near a light bulb ever again.

[@brycedelany8211]

I was just about to say that, it’s so bad! like that’s the kind of lighting you would use for dance not for an interview. It’s so distracting, there’s a black line down the middle of his head and face.

[@TehBurek]

@@brycedelany8211 Yeah, it's pretty bad, and it's strange how they didn't notice and correct it right away. But of course, I'm being hyperbolic here, it's not like they murdered anyone. You're ok, lighting person.

[@dirtypure2023]

@@TehBurek It was a deliberate choice. It's called "style" not sure if you've heard of the concept. They were clearly going for a semi-dramatic yet personal tone. Just because you were distracted or annoyed by it, doesn't mean anyone else cares or even noticed. Opinions are not objective.

[@TehBurek]

@@dirtypure2023 Nice condescension there. What's pretty objective is that their "style" is making it hard to see the face and eyes of the main subject. And that's annoying. Now, if you think that style is worth more than basic clarity and a pleasant viewing experience - that sure is subjective. And my opinion is that it's not. And of course I don't take this that seriously, I even clarified that in a previous reply, just in case. But it doesn't help. Also, about the "anyone else" part - just take a look at the rest of the comments. I'm even acknowledging it's redundant, as that's what so many comments are already about.

[@dirtypure2023]

@@TehBurek I just find it absurd that anyone cares that much given that the quality of information presented was excellent. All the top comments are about this subject, it's just petty and stupid. There are people that insist on raising a fuss and starting a miniature controversy on every other video on youtube, over issues that aren't even relevant to the subject matter. Why are people talking about light bulbs and not bridges? If they're so distracted by the lighting that they can't focus on the information presented, maybe they should seek help for attention deficit disorder.

[@bashbashbash9495]

bruh i just watched a 20 min video about bridges 💀💀💀 this dude is amazing they did him dirty with that lighting

[@STEMedia]

✊🏾

[@thomasposch4730]

me who is studying civil engineering: those are rookie numbers. gotta pump up those numbers.

[@dominic6634]

@@thomasposch4730 lol so you haven't worked in the field yet. Get ready for things being different.

[@tinab2053]

They need to do a follow up video with him just so he can get better lighting and he can talk about whatever he wants.

[@ijmurad470]

I think he would still want to talk about bridges.

[@georhodiumgeo9827]

@@ijmurad470 I’m ok with that.

[@ijmurad470]

@@georhodiumgeo9827 Me too, I never thought I would enjoy a 24 minute video about bridges.

[@sidhantjasrotia220]

He is a structural engineer, he can talk about different types of road intersections, different types of waterway infrastructure and I'm already interested

[@empressmarowynn]

@@sidhantjasrotia220 Yes! I would love someone to give an in-depth talk about highway interchanges.

[@user-ub3ix9du7i]

This dude must have honey in his voice how tf did 24 minutes of bridge talk look like 5

[@georgplaz]

honey in the larynx sounds like a serious condition 😳

[@larrybarnes1826]

@@georgplaz 13

[@larrybarnes1826]

V

[@ens0246]

@@georgplaz or a great album title!

[@STEMedia]

🤎🤎🤎

[@L.O.Hammmm]

Can't believe nobody else has pointed this out, but the lighting is amazing! Great job, really digging the whole "witness protection gotta hide this dude's identity" vibe

[@GalileoCap]

This guy is **really** good at explaining, I'd love to listen to him talk for longer!

[@STEMedia]

🤎

[@LashanR]

As someone who studied Civil Engineering with Architecture, thanks for reminding me what I actually did during my degree.

[@emm1944]

Oh wow! That's amazing! Was it a dual degree? I've always wanted to do that but can't in my country.

[@PunmasterSTP]

Out of curiosity, are you actively working as a civil engineer?

[@openingband]

This is like How It’s Made. I don’t care but I can’t look away.

[@albagonzalez9607]

😂😂😂

[@vince1000]

the best things about these videos are that if you didn't care at the start of the video, you definitely did by the end

[@closeupchannel4365]

That is the youtube algorithim.

[@vaishalibankar7491]

True

[@ShaudaySmith]

Thank you! I was about to say the same thing! I feel like i should be watching this at 3:30am....

[@TheEvox81]

I love watching smart people talk about something they are passionate about. There's such a subtle happiness on his face as he talks about something that a lot of people would find dull.

[@arthurmagalhaes2441]

Ok, i wasn't expecting to watch the whole video and be so drawn to bridges like that

[@chefdoomy]

The one in charge of the lighting needs to rethink this video.

[@zizo3959]

This guy loves bridges so much he even has one on top of his eyes

[@charlesdesouza9313]

underrated comment

[@uhohhotdog]

Lol

[@animeshr3324]

😜😜😜

[@madkirk7431]

I suggest he plays polybridge or polybridge 2. He'd probably have fun making a bridge that lifts up into another bridge.

[@atticusdodd4923]

If you actually pay attention, he doesn't have a unibrow.

[@everestlee3772]

Love how casual he sounds with this. He explains it so well with a great voice.

[@STEMedia]

🤎🤎🤎

[@melinapiccolo3526]

ok great I came to read the comments and i'm glad i'm not the only one complaining they could have done a better job on lighting his face. poor guy, deserved a lot more.

[@jonjoe1532]

Hi

[@DackxJaniels]

Wired: "Do people usually want to see the eyes of someone they are listening to?" Also Wired: "Nah"

[@NohStar]

the poor guy looks like he’s under a bridge with that shadow on his head

[@STEMedia]

😂🤷🏾‍♂️

[@Omnilatent]

Maybe that was the intention about the lightning lmao

[@iankane1733]

Definitely bad lighting.

[@NateCConcerts]

Shoutout Wired for getting interesting educators to talk about these topics, never thought I'd watch 24 minutes of bridge content!

[@FingeringThings]

This is an amazing answer to a question I never thought I had

[@STEMedia]

😂🤎

[@cwtan1446]

24 mins explained way better than 24 hours of my lecturer's teaching... Thumbs up to this guy

[@STEMedia]

:) lol

[@PunmasterSTP]

What class were you in?

[@EJ09090WRKZ]

I got my engineering license exam result today and I failed. This is therapeutic 🙃 EDIT: Thanks for the support y’all!

[@Josh729J]

u only fail when you stop trying

[@applejackzo]

Sorry man. You got it next time!!! Civil engineering?

[@EJ09090WRKZ]

@@applejackzo yeah man!

[@EJ09090WRKZ]

@@Josh729J i won’t! next attempt in April 😤

[@angelmonroy3012]

:( you’ll get em next time! go & change the engineering world

[@dougwoolery998]

As a third year civil Engineering student in Jamaica. I really enjoyed it, these are the people who should teach ppl, get them motivated and interested in the world of civil and structural engineering

[@Sinaeb]

narrator voice is too strong compared to the guy

[@jamesincharge]

Thank you. I'm happy I'm not the only one who thought so. The beginning was so jarring.

[@lithiumdeuteride]

It's too loud, and it's too dry. Reverb should have been added to make it sound more natural. And it needs a de-esser.

[@dogwalker666]

They could have checked how the script pronounced as well.

[@estebancollazo4883]

Did the interns film this one? Sorry I couldn’t concentrate when the lighting makes my guy look like ◼️ ▪️▪️▪️▪️ 👁◼️👁 ◼️ 👄

[@madkirk7431]

Ikr

[@sagnikpradhan3594]

Dude, those shadows on him arent great. My eyes are painful.

[@georgplaz]

your eyes are painful? don't look at me 🙈

[@sagnikpradhan3594]

@@georgplaz Oof

[@oscartorresrodriguez6545]

I got school tomorrow im gonna sleep early me in 1.30 am MMMM yes bridge

[@guyselway4865]

As a Londoner I was getting very worried that Tower Bridge wasn't going to be shown as an example of a moving Bridge. The relief when it got its own section was palpable 🤣

[@STEMedia]

💯🤎

[@VeryKuteB0y]

The direction of the arrows in the illustrations was really frustrating to watch. Isolate one member & show the forces acting on it, just randomly drawing arrows confuses the viewer.

[@petermgruhn]

Tell my students all time not to draw arrow pairs on their trusses. Ambiguous. Tell me you just drew tension and I'll explain why you drew compression. And the other way, too.

[@boyan2427]

I was thinking just the same thing. For sure those animations weren’t showed to the interviewee, because he knows what he’s talking about and the illustrations don’t.

[@nmb2107]

He was trying to illustrate for the lame person to get the idea!!!

[@suprvideo]

This is the sort of video I love - going in-depth with an engineer about how they think about a bridge conceptually, what design problems and constraints they have to address, and how the different solutions differ. This video is particularly well illustrated with animations over the images to emphasizing their points.

[@Kevy_G]

soo a long boat that got stuck between two bits of land?

[@lucbloom]

Go to Tom Scott’s channel… you’ll be very pleasantly surprised. Amazing Places

[@suprvideo]

@@lucbloom I love his channel too. Always interesting

[@kaliavang3449]

Just a man who loves bridges :') wholesome content

[@STEMedia]

🤎🤎🤎

[@MG-ts1xs]

this guy came and gave a presentation at my school yesterday, he was awesome

[@davidshi451]

Looks like Wired needs a...lighting engineer!

[@dworkeen]

In all honesty and as a lighting guy it looked ok

[@kendesasiahaan6181]

I got school tomorrow im gonna sleep early me in 1.30 am *MMMM yes bridge*

[@onkelpappkov2666]

Test in school about types of bridges. successkid.jpg

[@jessicarolon3870]

ok great I came to read the comments and i'm glad i'm not the only one complaining they could have done a better job on lighting his face. poor guy, deserved a lot more.

[@insanitystrike]

The lighting showing us a brand new bridge type in his unishadow

[@markcapuano101]

The amount of sheer knowledge this dude has about bridges is insane. You can tell he's been studying them his whole life

[@STEMedia]

🤎

[@satkarsyangtan2280]

WIRED: **Shows photos of different types of bridges** Poly Bridge Players: Trust me, there's more

[@Exiled_Rouge]

I have watched this video. I am now a structural engineer in 24 minutes. Certainly, I could build anyone of these.

[@STEMedia]

😂😂😂

[@atomic.universe]

That guy is a great teacher. Those 24 minutes flew by! I hope he makes more videos

[@STEMedia]

🤎🤎🤎

[@cosleia]

The lighting on Dr. Mabry is insulting. That said, otherwise this video is fantastic. I enjoyed the interview format; he’s a very engaging speaker! And the b-roll and graphics of the different bridge types went right along with what he was saying. Really enjoyed it!

[@SebastianTheGreat]

That lighting makes it look like he’s in an anonymous confession video 😂 Is he worried that the bridges are going to be after him for snitching?

[@lonearrow]

Thank you Dr.Mabry and WIRED for such detailed video on the bridges.

[@STEMedia]

🤎💯

[@sidhantjasrotia220]

Lol as a civil engineering student it feels like I learnt much more than i ever had in the classes

[@EtheEvil]

I used KZbin and Khan for my first 2 years of Uni

[@mattc3738]

Anyone can build a bridge that stands, but only an engineer can build a bridge that barely stands

[@nicholas8479]

Reminds me of the one that collapsed at FIU.

[@STEMedia]

😂💯

[@Mrdardas99]

That was super interesting! Thanks for that! I hope you bring him back to discuss and analyze things like engineering disasters (the Tacoma bridge incident is amazing) even if they are not bridge related.

[@mnels5214]

Why was I so invested in a 25 minute video about bridges? How was this material so accessible and interesting? Great video. I have the same feelings a lot of other people do about the lighting, but still...this was fabulous.

[@STEMedia]

🤎🤎🤎

[@a_leis7]

Did the interns film this one? Sorry I couldn’t concentrate when the lighting makes my guy look like ◼️ ▪️▪️▪️▪️ 👁◼️👁 ◼️ 👄

[@J.5.M.]

Yeah the lighting on him was weird

[@jofab23]

I say it was very clever, they made a shadow bridge spanning his face.

[@hughmungus1767]

@Adrien Leis - Honestly, it looked to me like someone had split his head with an axe. I was halfway expecting his brains to be visible through the split. I didn't even notice at first but by the end I could barely think about anything else.

[@robertraymond762]

Hahahah

[@pinkywinky911]

Oohhh they showed the Kurushima Kaikyo Bridge! We just live less than 40 minutes away there. It’s beautiful and also a perfect pace to cycle since it’s in the Shimanami Kaido Cycling route 😁

[@DrNee]

Really enjoyed filming this. Thanks again for the opportunity @WIRED!

[@kornykev]

You should have him in a bonus episode talk about floating bridges

[@STEMedia]

💯

[@enveloreal]

Excellent video, a bit long though. Would love an *abridged* version.

[@chefdoomy]

Interesting content ruined by poor lighting on Dr. Mabry.

[@STEMedia]

✊🏾

[@cassieath]

As a current civil engineering student this was very educational and enjoyable :)

[@STEMedia]

💯💯💯

[@aca2410]

That’s rotating pedestrian bridge is amazing

[@laurencefraser]

Really looks like a safety issue. Normal draw bridge, someone trapped on it when it opens, unless they're an idiot or Exceptionally unlucky, will slide back down onto land. On the sort where the central section is lifted straight up, they're just stuck for the duration. This sort just flat out dumps them in the water. Further, it has a maximum clearance based on the arc of the curve. Draw bridges do not. Heck, if you've got room on the bank(s) and the water isn't too wide you can build a swing bridge! (Err... Wait, a swing bridge might be a different thing. Might have the names muddled.) It's basically just a beam mounted on a pivot. It swings Sideways, basically like a gate. Less mechanically complicated, only slightly more risk of dropping someone stuck on it into the water than a draw bridge, less than the rotating type actually used. The only problem is that if the sections are too long you have to cantilever them, which means a bigger chunk of the bank must be kept clear. Depending exactly how the thing is built they can be turned with a hand crank, or even just pushed (it's basically the same principle as a canal lock gate, just without the gate.)

[@STEMedia]

💯💯💯

[@LesileNeidig]

This was so interesting and easy to follow. He is such a good teacher and the charts with the highlighted information solidified my understanding of the explanation.

[@mulgerbill]

Nothing better than a person with deep knowledge of the subject and deeper enthusiasm.

[@charleyedwards2121]

i love these episodes! so informative and the over voiced questions are wonderful. THANK YOU to all the professionals who take time out of their days to inform us

[@STEMedia]

🤎🤎🤎

[@9millimia141]

This is what my dad does. Surprisingly most bridges are DECADES past due for repair... budget people are often not educated on the safety issues associated with this type of neglect.... just like the lighting person was not aware how badly he truly needed that spotlight that the production budget of this video did not allow for... Moral of the story... if you think a bridge looks unsafe or you have a strong gut feeling to avoid a bridge... you probably should. 😉

[@brightwriter]

Good info! Perhaps a sequel will include such things as pavement types on bridges vs. on ordinary ground, what to do when designing a bridge where ice can occur, and the use of interlacing beams and other compensations for thermal expansion and contraction. There is much to learn on this subject.

[@TheDudeSon49]

The female sounds too much of a voice over (instead of an interviewer) for me to not be annoyed with it. Also the ligting is throwing me off

[@arfyness]

Sure is distracting. They clearly didn't rig both of them with similar mics in the same acoustic environment. Maybe she's a robot! Just a speaker under the camera.

[@ShuAbLe]

And her scripted questions don't add to much, maybe just the guy explaining would be better, the female voice feels like an interruption, there's no dialogue About the bridges themselves I learned a lot

[@naciyemaldar5199]

I cannot thank you enough for this video. I am making a bridge project with my 4th-grade students, this video covered everything needed and even more!!!! Thank you, thank you thank you.......

[@Aedar]

Really interesting video, one thing I'd like to say about the bailey bridges, while they are/were supposed to be temporary, they were usually really well made. The US army left some bridges in my country after WW2, and some are still operating today... Sure usually they can't carry very heavy weights anymore and stuff like that but there was a bailey bridge between 2 villages near my town that was working as actual road bridge (as in, not just for pedestrians but also for cars) until last year... AFAIK they didn't actually demolish it, but instead took it apart and rebuilt it in some military history museum... And as for stone arch bridges being able to last long, we have multiple very old stone bridges here in europe, not just the aquaduct, for example the Charles Bridge, built in 1348, in Prague is my favourite, and it can carry an incredible load... Well an incredible amount of overweight american tourists, but that's a great load bearing test imo :D

[@willalexander1439]

I just watched 24 minutes of bridges and I enjoyed it.😂 Thanks wired

[@STEMedia]

😂😂😂

[@juliacronin7303]

Why does the voice over sound like an out-of-control AI trying to seduce a human?

[@uzefulvideos3440]

lol

[@gutersteinker]

Hahaha jokes of the future

[@yumikotanashi]

Lmao

[@stachowi]

Keep making more of these kinds of videos... I found this very fascinating.

[@dominiksulzer1338]

who tf did that lighting should be fired

[@nouphal8948]

not fired but given a feedback.

[@shreyashkumar2473]

@@nouphal8948 u havv my respect

[@georgplaz]

@@nouphal8948 take that nuance out of here! Don't you know you are on the internet? no, jk. Much appreciated ❤️

[@dominiksulzer1338]

@@nouphal8948 I would give him feedback on a paper called termination form.

[@mememan3279]

@@dominiksulzer1338 then he is lucky you're not his boss or of anyone's boss for that matter

[@haydenmaines5905]

This was a fascinating and brilliant video! Would definitely appreciate more like this!

[@Maouww]

And this is why we don't use symmetrical lighting for interviews :D

[@LasseHG1]

Would love to know if suspensions bridges are best used over rivers and in earthquake areas, why the great belt bridge is a suspensions bridge, considering it is in Denmark which doesn’t really have any earthquakes and it’s over a ocean.

[@lawrence2483]

late to the game but it's because it's likely a major shipping lane. The suspension allows great distances between piers for more traffic to go through at once without putting any risk into ship or infrastructure.

[@dj3511]

Simply, BRILLIANT ! much needed for my final year project ! Thank you Dr Mabry!

[@nathanceniza9476]

As a student studying civil engineering I’m happy I understand most of these terms. :)

[@STEMedia]

💯🤎

[@matthewfickling4441]

Nice to see the Winking Eye getting the mention, and glad they actually showed footage of it moving, but it sounds like he says Millennial Bridge. Another Tyne bridge appears in the bridge type list at 0:12, with the Swing Bridge for a swing bridge.

[@hanibachi3719]

Can't believe they didn't mention anything about the Netherlands! The heaven of bridges

[@STEMedia]

🤔

[@MrLionvibration]

turn the lights on?

[@MichaelJOneill333]

This guy is so good at explaining this. I learned alot! Thank you.

[@shasha1146]

How can one person be so knowledgeable ? Im impressed.

[@blsharpley]

I suddenly want this man to teach me everything

[@Felipera_]

Jokes on you, Ive beaten polybridge

[@sador111]

everyone: lighting in this viddeo is bad me: amount of popping in voice-over is unreal

[@edgelord0923]

I’m three classes in to my structures class in architecture school and the terminology and theory in this matches exactly!

[@LinXiaoChaun]

At 12:52, the entry for the Truss Bridge Type: "Fracture critical (no load path redundancy)". Regrettably, Dr. Mabry does not discuss this matter in the video. But this aspect of the truss bridge is really important. A number of truss structure failures hinge on this failure mode. Engineers take note. Also, the matter of why one type of bridge structure is selected over another in a particular situation is not discussed. Oh, well.

[@garyanderson5031]

You forgot floating bridges. We have three floating bridges in Washington State each over a mile long. One will soon have light rail trains crossing it.

[@maceygrace9406]

This man makes bridges both interesting and easy to understand!!!

[@Flowtslan]

It's been a rough day, and I just watched a 30 minute video about bridges

[@PunmasterSTP]

As a engineering nerd, this video really scratched an itch! I think I'd looked up some stuff on bridges in the past, but this helped clarify my understanding and was cool to watch. On a side note, why was the lighting so dark in the interview room? I couldn't even see all of Dr. Mabry's face.

[@MorenajeRD]

this video is almost perfect........... but the lighting........

[@moisesmunoz3844]

This was extremely informative and interesting.

[@maryrosekent8223]

I crossed the U Bein bridge in 2001. The far side (west?) is decidedly more chill than the east side, and it’s rather rickety in some places, which made it a bit of an adventure. EDIT: That’s Shwedagon Paya in the background, one of Myanmar’s most holy temples.

[@STEMedia]

Oh wow, that's so cool!

[@maryrosekent8223]

@@STEMedia It was an amazing year for me-I spent one year and two days traveling around Southeast Asia and saw some amazing places.

[@STEMedia]

@@maryrosekent8223 That is really interesting. I hope to visit it in person someday.

[@maryrosekent8223]

@@STEMedia I hope you get a chance while it’s still structurally sound enough for crossing.

[@citiaii]

wonderful video! well spoken and i love the way he laughs occasionally, sounds so calming. building a mock up bridge that could take loads, this video helped a lot!!

[@TheLiamster]

My favourite bridges are suspension bridges and cable stayed bridges.

[@STEMedia]

Same here!

[@rishavmandal285]

@@STEMedia they look great but are not the strongest one

[@MrGoldInfinity]

The closest humanity came to being spiders

[@rebeccadubois6536]

Excellent informative video. Right up my alley. Many thanks for creating it and the job you do, Dr. Mabry!

[@eileenmorrell4942]

Great job explaining in simple terms complex engineering principles.

[@reesejones3957]

Who ever did the lightning cut this man in half with a shadow

[@jimlawton4184]

I appreciate all the knowledge he's sharing! Also I wanted to point out that the Golden Gate Bridge is International Orange, NOT red

[@Zaihanisme]

Popular media portrays the colour as a rusty red, tho

[@jimlawton4184]

@@Zaihanisme for years I thought it was red too! I think it just looks red on camera or maybe is a redder shade of orange

[@4Shaman20]

I kept thinking my Alexa was going off everytime they introduced a new bridge type.

[@savannahlsteele]

Thank you WIRED x Dr. Mabry!

[@STEMedia]

It was a pleasure :)

[@jamesrosko]

Dr Mabry was great. Whoever mixed the sound made the voiceover lady sound awful, I didn't like hearing her.

[@STEMedia]

🤎

[@hxmr]

The one in charge of the lighting needs to rethink this video.

[@Mrs_Roselle]

I watched this in my classroom today and I LOVED IT REEEEE XD ITS AMAZING HOW THIS WORKS!

[@bigpopakap]

12:37 I'm glad he still enjoys the little things

[@mathwithjanine]

Wow this is so fascinating! Such a great explanation!

[@STEMedia]

🤎🤎🤎

[@drewjarrell2667]

They really need 3 point lighting lmao

[@AdamSmith-gs2dv]

Suspension, Cable Stayed, and Cantilever bridges are the most beautiful design wise

[@STEMedia]

Agreed 💯💯💯

[@dfgdfg_]

The gateshead millennium bridge - the winking eye one is awesome!