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@The Engineering Hub You have the gift, my friend. This is the best introduction to structural shapes and selection I've ever come across. When I was getting a bachelor's and master's in architecture, many courses failed to properly create an overview of the subject matter, but you get that right in just the first 45 seconds. Most who purport to teach get bogged down in details and trivia, get sidetracked, or don't really understand their audience. Here on the other hand, at 2:00, you include the comparatively complex equation for buckling, but without distracting from what a novice needs to know. Really quite extraordinary. Many thanks!
Have another look at the cross section of rolled channel iron. You will notice how they have more material at the bends inside, rounding the section, and the base is usally thicker than the wings. They are not half an i beam! Also the way they are rolled makes them more dense than other profiles. You'll notice the forge when cutting. They are a beast of their own.
I'm retired mechanical designer. . .We used STAAD structural analysis software in the 1980's . . . Cell Phone towers have wind load and ice build-up weight, so hollow was good.. . . .acid plants have corrosion problems with hollow members, so hollow was bad. . . .channels and angle iron have totally different applications. . .and Equipment supports made of tubular members need extra flanges welded on to attach Electric / Hydraulic lines, so I-Beams are perfect for 1 and 2 story equipment platforms. . . .Every situation is unique.
I'm an immortal highlander who has been blacksmithing since medieval times & doing structural engineering with steel for 135 years, and I learned more from this video than during my entire cursed existence.
Hurricane Katrina gave a great opportunity for the observation of structural steel failures. There were hundreds of tall billboards in and around New Orleans. Unfortunately, I cannot give the weight per foot of the supports but I can say that the external dimensions were similar. Some billboards were mounted on three or four I-beams of constant dimension. Others were mounted similarly on round pipe of diminishing cross sections as the height increased. Peak winds were in excess of 150 mph (240 kph). My observation was that I did not see a single billboard on I-beams that was still standing after the hurricane. All of the I-beams failed by bending, not buckling, over a radius of several feet parallel to the webs of the I-beams. The bends were remarkably gentle, on the order of a 3'-5' radius. Once the I-beams gave way, the billboards themselves were pushed to or nearly to the ground. I did not see any billboards that were on pipe fail. The hollow round shape stood up to the wind very well.
Wind loads on billboard (in reality) create more torsion than bending. Wide flanges still better in bending and circular sections are better in torsion, that is why you see more circular supports still standing for billboard structures.
Have any of you any practical experience installing HSS column over a h-beam column no I seen one comment dude said he was going to use pipe obviously has never made a column out of pipe if you had 10 HSS 12 x 12 by 5/8 on one side and 10 on the other side with a space of 10ft between sides and 8 ft between columns and a top of beam height of 10 ft and you built comparable structures The h-beam Columns would have less lateral movement when you were walking across the structure it's often fun to take Engineers on a deck when they don't have a clue and see the reaction on their face when they stand still and feel someone walk across a structure that has HSS columns and that would be multiple X bracing to combat thing down so the problem with that is on a boat dock when they have the boats at the bottom and the deck on the top they engineer a lower structure made of rock or fuel to get to the sheer out of the building
I think it is a bit strange to rate H- beams higher than square hollow profiles when it comes to workability. For welded constructions the fabrication cost for H-beam based structures are typically 3-4 times compared to square hollow profiles. Due to more complex prefab (cutting and weld prep), more complex welding and NDT and more time consuming surface treatment. Another huge benefit with square hollow profiles is that the other geometry is constant. If you increase wall thickness it builds inwards. Meaning in 3D models there are no changes to overall dimensions and joints if one changes wall thickness. With H-beams everything changes. I would chose square hollow profiles whenever possible.
When it comes to surface treatment open sections are vastly superior. The entire surface is easily treated, while hollow sections often suffer from poor treatment on the inside (if they even try to galanize it properly). Also the enclosed spaces are suspectible for trapping moisutre thus accelerationg corrosion. As for workablility it depends what your goals are. Bolted connection are much easier to make using I beams. As for 3D models with a well built up model in a modern software its incredibly easy to change section sizes. When it comes to smaller welded structures with lsmall loads square tubes can be advantageous indeed. But also depends on a lot on the application and I beams can be better dispite the slightly more welding required.
H beams give unlimited easy attachement capabilites, as someone who has to constantly do rigging and installation of large equipment/ installation of necessary plumbing and other support accessories, beams are just easy.
@@istvanditamas2959 Yeah, the automotive industry switched from C channel to box channel. While the box was somewhat lighter thinner metal and controlled twisting better, it trapped moisture and got poor rust treatment inside. While the I-beam is incredibly strong, it fails much quicker under high heat than wood laminated. The extremely dense laminated beam will only char the outside, while the steel will twist and fail above 2,000F.
Love the use of radar plots, this is an ideal situation for using them. I also can't believe it never occurred to me that the framing+sheathing in home construction created a compound I/T shape for strain calculation purposes!!!
I'm not an engineer or construction dude. When putting up a shed a couple years ago, once all the walls and roof trusses were up it seemed pretty rigid. Once the sheathing was on it _was_ very rigid. That's a lot of "triangles" working for you (triangles formed by fasteners through the sheathing - whether walls or roof). The tension on the roof truss horizontal beams becomes the hero of the project, actually.
Before watching, my answer to the question in the title was, "All of them. Depending on what you are looking for from the shape and material." As an example, it's hard to pump water anywhere using an I-beam.
While not really part of the data visualization, an awesome but rarely used part of computer interface is a three-variable slider, which is visualized as a triangle, with each point in the triangle being a different distribution between the three options. It could be used as a data visualization for some things too, like "time spent working/sleeping/other" with every point on the triangle being a different set of these three numbers with a constant sum.
I would have tought this was common knowledge ... build a basic box ... if you start with the sides it is great top to bottom but may not stay square as it wobbles ... add a bottom and poof it goes rigid ... I learned that back when I was about 8 years old building a birdhouse for cubs ... it was a royal pain getting all the sides to stay square ... then the dad showed me the easy way ... start at the bottom and work around ... each addition adds strength ... to the last ... no more fiddling with square
Developing an intuitive sense of the effect of displacement of material from the neutral axis is a valuable design skill that can be only partially replaced by CAD and simulation software but a team's design effectiveness is significantly enhanced if both the software tools and the intuition are effectively utilised within the team.
@@ESALTEREGO No, it's a padding problem. Most 15 minute videos are 1 minute of actual useful information and 14 minutes of "Like and subscribe to my channel", "see our patreon here ...", "join us on discord...", "today's sponsor is: ...", jokes, side-tracks, history of, explaining basic concepts that should really just be a reference to another video.
@@soylentgreenb add is a thing too! I know I’m on a good vid if I don’t start scrolling… I’m typing this with playback speed at 1.5, less than one minute in… now I gotta back up
Another good thing the hollow sections have is that you can make composite columns with them. Helps in the workability when you pour the concrete in. Also, it has more resistance than a normal hollow section due to the interaction of the hollow section and the concrete column, meaning it can result in having even longer span of elements than with a steel section alone.
Thank you for this interesting and informative video. Three other properties occur to me: Crushing (eg elephant sits on a tube) Crippling - relates to length/stiffness in and end-load situation (eg elephant sits on a platform atop a long tube) Impact strength (eg car veers off the road and hits a structural member, or any day in a war situation)
To answer why these are not included; crushing is better known as the compressive strength and, ignoring buckling, it is directly related to the area of the section; crippling is better known as global buckling which is addressed in the video; and impact will relate to local buckling and material properties, assuming we are only using steel, then it is also addressed in the video. Have a look into global and local buckling then I’m sure you’ll have a better understanding how those concepts are related
I am an Engineer.I covered,Strength of Materials,Mechanical Systems,Engineering Design and Mechanical Technology. Beam Shapes and Hollow Section Profiles as stated in the video,depend on many factors. Nowadays there are many newer materials in existence ,compared to when I started my Higher Education and Training in Engineering. Composites and Nano-Materials are a few.
I've worked with U Channel beams, and for their weight, they got quite good bending strength. Certeinly, a good option for longe free span structures without much torsion loads... Anyway. Nice video man.
@makermartin10 - How about U-Channels attached to Tubular Cores? Or Square Tubes fitted with Round Types, internally? Adhesive Bonding, Welding (via Rosette Welds from the Square Tube in Circular Openings, not too big), or Bolting Through, to transfer and Share Loads!
@9:13 those are not structural pipes but Fire Protection. the "victaulic" grooved couplings that you call "collars" are only meant to join the pipe to convey fluid not add reinforcement to the building
My opinion: Circular hollow (but not too thin wall) for torsion and for carrying fluids (literally a pipe) Circular solid for dynamic crankshafts (like transmission and engine shafts) Square hollow for smallish columns H-beam for large columns (possibly embedded into a concrete pillar) I-beam for any type of uniaxial bending about x-axis (such as a beam supporting only weight of gravity) I-beam for columns, if braced in the y-axis Angles for connecting other beams together Rectangular solid for any type of wood (this is also the only type available for wood generally) Channels for embedding needs T-sections are more or less outclassed by I-beams for most applications (also calculating the moment of inertia for T-sections is a huge pain in the ass)
It’s amazing how some people can take something so natural and common sensical as balance and strength of an object and complicate the Hell out of it with unnecessarily complex or obscure words, diagrams and formulae, for what should come as intuitive awareness or knowledge to others. I guess not everyone is cut out for engineering.
Excellent video, this explains the pros/cons of structural shapes much better than conventional resources and curriculum. The school of TH-cam is putting colleges in their place, they better embrace it and adapt or they'll become outdated.
I often see elliptical tubing used for things like motorcycle and aviation framing/support elements... in talking about wood framing, sheathing, with adhesives, seems to offer a big advantage in making a kind of 'tubular', or even, monocoque, structure, with much added stability. Thanks for an interesting presentation, and interesting graphical/numerical scoring method(s).
I had forgotten about elliptical tubing. It seems to combine the properties of circular pipe with the properties of hollow rectangular tubes. I first saw them being used for reducing weight on bicycle frames while increasing bend resistance in the commonly loaded direction.
Channels and angles also deflect rotationally under bending, especially when cantilevered. They make poor beams when the load is placed perpendicular to the flanges. As one commenter notes below they walk off access to the direction of the load. Triangular shapes are actually better in bending than square shapes of equal area and, when extruded, extra material can be placed at the corners to maximize section modulus. Unintuitively, symmetry is good. Connectivity is of course horrible. I would be interested to see your analysis of solid and hollow triangular sections.
Very good point about rotational deflection under bending. In fact, we happen to be developing our next video on this very topic! Noted on your comment about triangular sections. We'll look into this more and see if we come up with anything. Cheers!
Log cabins with almost round solid circles (flat at top and bottom if I don't recall wrong) would have been lovely to see here even if it's not a modern approach. Curved wood was also used back in the day for certain roles, think of the wood where a branch leaves the tree or in the roots etc. I'm no expert on that kind of things, but I'd love to learn more.
Nice video! I liked the side-by-side rankings of the different shapes. Another great video would be if you delved more into the bracing, connection, or other practices that improve on the relative weaknesses on each type of section.
It can be noted that the Double-T Precast concrete beams mentioned at @11:41 which are commonly used in parking garages and bridge decks are structurally somewhat different than simple metal t-shapes as the required included reinforcement is nearly always pre and/or post-tensioned steel rods and/or cables. this significantly increases the bending resistance of the complete part.
Very well done. I'd be interest in a follow up video where multiple shapes are combined. adding an angle to a flat surface creating a triangle, and combining triangles to make a honeycomb.
I am building a full-length (19.5 ft) pipe rack for a pickup truck. The longitudinal pipe (back bumper to front bumper) needs to be strong enough to be able to haul heavy cargo. I have posed the question to friends about what size square tubing should be used and I have received several confusing explanations about this design. Keep in mind that I have to keep it as lightweight as possible. The first method is to use a single 2x1 thin-walled square tube to run the length of the rack. The second method is to use "two" 1x1 thin-walled square tubes either welded together or bolted together in order to make a final 2x1 length. I was told that the more angles that you have on a span the stronger the span will be. The other thought is that a consistent uniform design (2x1) will be stronger. Which would you prefer and why? Thanks.
Cool video, I like your rating method! The only thing is that the transverse stiffener shown at 5:03 does not improve torsional resistance, it improves local web buckling. Torsional stiffeners would need to run down the axis of the beam closing the section for the entire length of the beam loaded with the torque. Great video otherwise!
I am constructing a small home on 1500 squarefeet plot. Traditionally, constructions in my area is done by raising 12 RCC pillars (columns) on the plot before pouring concrete to form a flat roof. From this roof and above, residential quarters begin where each floor raised above the column is considered independent residential units. I, on the other hand, prefer a mezzanine construction on my 1500 squarefeet area. Purely for personal use. So my priorities are lightweight and economical materials versus the traditional RCC columns that need steel bars concrete mix. Would I be wrong if I prefer H or I beams instead of traditional RCC column for framing the structure to lessen the concrete use? Would it be economical and would I be able to achieve better structural strength than RCC columns?
Since the comparisons were based on equal cross sectional area (in other words for a given material the same weight per length) the analysis tended to obscure the strength per weight. If building something like a race car chassis where weight matters a lot, it's impossible to beat round tube. But cutting it to make joints does require special equipment and skills. You can buy jigs that use just a hand drill and hole saw, but getting the measurements and angles right takes thinking and attention. Square tube is a second place. The weight is higher for the same strength but welding joints is as easy as it gets. A handheld band saw will allow you to make just about any joint between two square tubes that you can imagine. I was surprised that he rated workability so low for square tube. But he was looking at bolted connections more than welded. It's just that among DIYers the people needed to choose different steel shapes are probably mostly people that can weld
Instead of surrounding rebars with concrete, how about filling hollow pipes with concrete. Or fill with resin for smaller structures like furniture. This would reduce the chance of buckling since the internal fillers are solid and resist compression.
when bending angle over a long span, it's interesting because it will dive or climb in the axis that you aren't bending and will have to compensate for
Helpful video, thanks. I would say that workability depends a lot on the tools available for a given material and shape. Having the appropriate tools can make the workability much easier. And not having them can make anything difficult. All that is to say I would not have given workability as much weight as it is given. Or, in practice, weight it in light of the available resources.
Yeah, workability is a bit of a strange category to me. I also don't see how I-beams are more workable than hollow rectangular tubes. If you have to trim out an I-beam, it gets pretty awkward for where to attach your stuff. But trimming out a hollow rectangular tube wouldn't be that hard IMO.
Anyone that knows what "area moment" and "section modulus" are already knows the answers to these questions. Those that don't are not being helped by throwing in words that are not familiar.
Fair video, i would have liked in the conclusion to highlight framing outside of wooden construction with the correct fastening and alignment many flaws in each element can be reduced
I’ve used almost all of those at my work at the Utah Water Research Laboratory making models for the customers. There’s a lot that goes into model building that’s very similar to a lot of trades.
I would say it is a very well informed purely scholarly approach with some notable gaps in real world knowledge and experience. For example the double T bridge sections he described. Those are generally post tensioned with cables for the strength of the structure rather than relying on rebar that is only contained in each individual section and doesn’t transfer load. He also ignored how the shapes he discussed are used as part of a larger system and the loading in each member is influenced by other members. And the shapes he deems less worthy are great at transferring smaller loads between more larger examples of ideal shapes.
Here in the Philippines we call it pipe instead of circular hollow, Square pipe for rectangular hollow, round bar for circular solid and square bar for rectangular solid.
Hi Jezreel, Very interesting terminology--square pipe! All the rest of the terms are the same as we generally use in Canada. For this video we used the terminology circular hollow and circular solid to aid parallelism in our verbiage, but we would normally just call them pipes.
Excellent overview. Like the rating system. I weld pipe. Don't like the unsafe person cutting steel at 10:33. No glove, no cutting wheel guard is a bad idea.
There are many structural shapes because different loads required difference design considerations. No one is BEST for all things, but each has it's place. There are no winners or losers.
When you position material furthest from the centre, and then make a cellular character within the outer wall, with cross ties to reduce buckling risk, congratulations, you have invented a stem of grass, or bamboo.
You correctly inform us that we need to select our section acording to the application. Therefore there can not be a clear winner. You say the torsion in an I beam depends on its 'J'. If you mean 'J' as it is usually understod, IE Ix+Iy then you are wrong. It depends on its 'K' which is much less. I recomment Roarks formulae for stress and strain for a better understanding. 'U' or 'C' sections have a further disadvantage to the doubly symetric 'I' in that they have a shear centre outside of the section which can easily lead to combined bending and torsion when loaded with simple shear. From a practical point of view, closed sections are difficult to treat against corrosion and equally difficult to inspect, unless of course you can get inside it eg the leg of an oil rig.
Hi again Emma, by J we mean the ''torsional constant J'' and not the polar moment of inertia or the summation of the moment of inertia about the x and y axes. Check out Chapter 3.10 in Mechanics of Materials by Gere, the twisting of noncircular prismatic shafts and the torsional constant are explained there. The factor K in ''Roark's formulae for stress and strain'' is the same factor that Gere calls J and is the torsional constant. In regards to the shear center, we agree that this is an important point that is worth mentioning. Maybe we can do another video only on the shear center of sections in a future video. Thanks for the good discussion as always.
You got a like how some of this engineered wood products mimic the cross-section of an I-beam. You have two two by fours with a groove cut in them with a jointer of plywood. The end up being lighter than a typical Lumber member but you have a bit more convenience on putting holes through for plumbing and electrical for example
Paintability (e.g. corrosion protection/inspection) is a big disadvantage to closed, hollow sections. Could be baked into the Workability metric, but could be a game-changer alone.
On the other hand, the structure could be designed so that the inside is sealed up so it doesn’t matter. This is most likely the case anyways when the ends need to be welded up.
Good overview!!! An error at 5:02: Those stiffeners will help nothing against torsion!!! On should add them on the sides over the length of the I-beam (to give it a tube shape).
I have always wondered about triangular shapes like trusses. Triangles are geometrically rigid by definition. I can see them buckling unless you put in a compensating truss. Your thoughts?
I am stricken by the extent of variety in shapes chosen by the state highway agencies in various American states for the identical task: posts for small highway signage. Right off the top of my head, I can think of various states that use perforated hat channel, perforated square hollow, circular hollow, and square solid (wood). Surely each has advantages and disadvantages, but one would think that more consensus would have developed as to which is the best value over the long term.
6:27 - - *THIN PLATES BUCKLING UNDER STRESS* 6:58 - - *Rectangular + square sections can be OPTIMIZED by creating hollow sections (or tubes)* 13:00 - - How would a *hexagonal* hollow cell/member rate on this score-system?
NICE AND CONCISE ! angles actually of 2 types the between 2 objects that uv shown and the surface angle. the 2nd 1 shows much much greter bending resistnce
the answer is; It depends on what you're trying to build. If it's something, like a simple garden shed, then maybe use one of those L shaped pieces in the corner for some support.
What about tension and compression? And the planes of tension/compression. T shape, round, square, and angle are used alot in truss systems. Analysts and design was fun, i became to see the formulas in the 3d spaces.
I was going to make a very similar comment. Angles are used in tension on the bottom cord of many flat roof trusses. And welded connections can not be ignored when discussing workability of structural steel. As another commenter pointed out, many times the decision comes down to cold hard cash. What is the cheapest way to meet the requirements without exceeding them. Many times designers create impossible conditions that can’t be fabricated in the real world. So I am not sure how much I trust them to care about what the constructors go through.
Several years ago at work, we needed to install some bollards. My suggestion was to slip a square, I, or triangle tube into a circular tube or a circular tube into a square tube to increase bend resistance. What are your thoughts on combining shapes looking just at the factor of bend strength?
Bollards are designed to stop smart people and slow down idiots. If bollards were made stronger the risk of injury would increase. Cars have crumple zones for a reason. Oh and a single thin wall pile filled with concrete is cheaper than the fancy strong design.
Sorry, extremely valuable and sensitive equipment that MUST work at all times. After getting called out a few times at 2AM when it was raining sideways to repair the damage caused by some dimwitted moron that couldn't control his vehicle - I really don't care HOW damaged the vehicle OR injured the dimwitted retard gets.
Can you make video on structural members used in brigdes like about rectangular column, cylindrical column,why they have fillet in some parts,why they have low depth at ends but high at centres in beams etc.
Aside from the complexity of manufacture, the flat faces would make attachments easy, as long as you make allowances for the work face possibly being 30 degrees from your desired orientation.
@@MonkeyJedi99 yes, I'm aware of shortcomings in manufacture and connection to other structures, but since a triangle is considered a pretty strong structure, I'd really like to know how it compares to the other shapes in performance.
I think an IV and could be the strongest. In eighth grade we had a science project where we had to build a bridge out of popsicle sticks we had a certain number of popsicle sticks and a specific amount of glue we were able to use. It was a competition throughout the whole school. I won that year my bridge held a 145 pound girl without breaking we had to use this girl because we ran out of weights to put on it.
Visit brilliant.org/TheEngineeringHub/ to get started learning STEM for free, and the first 200 people will get 20% off their annual premium subscription.
@The Engineering Hub You have the gift, my friend. This is the best introduction to structural shapes and selection I've ever come across. When I was getting a bachelor's and master's in architecture, many courses failed to properly create an overview of the subject matter, but you get that right in just the first 45 seconds. Most who purport to teach get bogged down in details and trivia, get sidetracked, or don't really understand their audience. Here on the other hand, at 2:00, you include the comparatively complex equation for buckling, but without distracting from what a novice needs to know. Really quite extraordinary. Many thanks!
Have another look at the cross section of rolled channel iron. You will notice how they have more material at the bends inside, rounding the section, and the base is usally thicker than the wings. They are not half an i beam! Also the way they are rolled makes them more dense than other profiles. You'll notice the forge when cutting. They are a beast of their own.
@@SynomDroni thanks Synom! I see what you mean about that 🙏🏼
What about shapes like ➕ & 🔼🔺both hollow and solid
I'm retired mechanical designer. . .We used STAAD structural analysis software in the 1980's . . . Cell Phone towers have wind load and ice build-up weight, so hollow was good.. . . .acid plants have corrosion problems with hollow members, so hollow was bad. . . .channels and angle iron have totally different applications. . .and Equipment supports made of tubular members need extra flanges welded on to attach Electric / Hydraulic lines, so I-Beams are perfect for 1 and 2 story equipment platforms. . . .Every situation is unique.
I'm an immortal highlander who has been blacksmithing since medieval times & doing structural engineering with steel for 135 years, and I learned more from this video than during my entire cursed existence.
There can be only one.
Still on the “old math” huh?
Hurricane Katrina gave a great opportunity for the observation of structural steel failures. There were hundreds of tall billboards in and around New Orleans. Unfortunately, I cannot give the weight per foot of the supports but I can say that the external dimensions were similar. Some billboards were mounted on three or four I-beams of constant dimension. Others were mounted similarly on round pipe of diminishing cross sections as the height increased. Peak winds were in excess of 150 mph (240 kph).
My observation was that I did not see a single billboard on I-beams that was still standing after the hurricane. All of the I-beams failed by bending, not buckling, over a radius of several feet parallel to the webs of the I-beams. The bends were remarkably gentle, on the order of a 3'-5' radius. Once the I-beams gave way, the billboards themselves were pushed to or nearly to the ground. I did not see any billboards that were on pipe fail. The hollow round shape stood up to the wind very well.
Wind loads on billboard (in reality) create more torsion than bending. Wide flanges still better in bending and circular sections are better in torsion, that is why you see more circular supports still standing for billboard structures.
Wind loads (in reality) are fluctuating thus it creates more torsion than bending loads.
Have any of you any practical experience installing HSS column over a h-beam column no I seen one comment dude said he was going to use pipe obviously has never made a column out of pipe if you had 10 HSS 12 x 12 by 5/8 on one side and 10 on the other side with a space of 10ft between sides and 8 ft between columns and a top of beam height of 10 ft and you built comparable structures The h-beam Columns would have less lateral movement when you were walking across the structure it's often fun to take Engineers on a deck when they don't have a clue and see the reaction on their face when they stand still and feel someone walk across a structure that has HSS columns and that would be multiple X bracing to combat thing down so the problem with that is on a boat dock when they have the boats at the bottom and the deck on the top they engineer a lower structure made of rock or fuel to get to the sheer out of the building
I think it is a bit strange to rate H- beams higher than square hollow profiles when it comes to workability. For welded constructions the fabrication cost for H-beam based structures are typically 3-4 times compared to square hollow profiles. Due to more complex prefab (cutting and weld prep), more complex welding and NDT and more time consuming surface treatment. Another huge benefit with square hollow profiles is that the other geometry is constant. If you increase wall thickness it builds inwards. Meaning in 3D models there are no changes to overall dimensions and joints if one changes wall thickness. With H-beams everything changes. I would chose square hollow profiles whenever possible.
When it comes to surface treatment open sections are vastly superior. The entire surface is easily treated, while hollow sections often suffer from poor treatment on the inside (if they even try to galanize it properly). Also the enclosed spaces are suspectible for trapping moisutre thus accelerationg corrosion.
As for workablility it depends what your goals are. Bolted connection are much easier to make using I beams. As for 3D models with a well built up model in a modern software its incredibly easy to change section sizes.
When it comes to smaller welded structures with lsmall loads square tubes can be advantageous indeed. But also depends on a lot on the application and I beams can be better dispite the slightly more welding required.
H beams give unlimited easy attachement capabilites, as someone who has to constantly do rigging and installation of large equipment/ installation of necessary plumbing and other support accessories, beams are just easy.
yeah I dunno why he said what he said about the limitations of H beams before then giving it a nearly perfect rating..
@@istvanditamas2959 Yeah, the automotive industry switched from C channel to box channel. While the box was somewhat lighter thinner metal and controlled twisting better, it trapped moisture and got poor rust treatment inside. While the I-beam is incredibly strong, it fails much quicker under high heat than wood laminated. The extremely dense laminated beam will only char the outside, while the steel will twist and fail above 2,000F.
This video seems misleading especially the title. Every single beam has its purpose and use case, why "rate" them in this way?
Love the use of radar plots, this is an ideal situation for using them.
I also can't believe it never occurred to me that the framing+sheathing in home construction created a compound I/T shape for strain calculation purposes!!!
Thanks for the feedback Adam!
I'm not an engineer or construction dude. When putting up a shed a couple years ago, once all the walls and roof trusses were up it seemed pretty rigid. Once the sheathing was on it _was_ very rigid. That's a lot of "triangles" working for you (triangles formed by fasteners through the sheathing - whether walls or roof). The tension on the roof truss horizontal beams becomes the hero of the project, actually.
Before watching, my answer to the question in the title was, "All of them. Depending on what you are looking for from the shape and material."
As an example, it's hard to pump water anywhere using an I-beam.
While not really part of the data visualization, an awesome but rarely used part of computer interface is a three-variable slider, which is visualized as a triangle, with each point in the triangle being a different distribution between the three options.
It could be used as a data visualization for some things too, like "time spent working/sleeping/other" with every point on the triangle being a different set of these three numbers with a constant sum.
I would have tought this was common knowledge ... build a basic box ... if you start with the sides it is great top to bottom but may not stay square as it wobbles ... add a bottom and poof it goes rigid ... I learned that back when I was about 8 years old building a birdhouse for cubs ... it was a royal pain getting all the sides to stay square ... then the dad showed me the easy way ... start at the bottom and work around ... each addition adds strength ... to the last ... no more fiddling with square
Developing an intuitive sense of the effect of displacement of material from the neutral axis is a valuable design skill that can be only partially replaced by CAD and simulation software but a team's design effectiveness is significantly enhanced if both the software tools and the intuition are effectively utilised within the team.
A follow up with real scenarios and what (+ why) a certain option was best would be great!
Wow, a 15-minute video that actually kept my attention!
Sorry but looks like an "You" problem
@@ESALTEREGO No, it's a padding problem. Most 15 minute videos are 1 minute of actual useful information and 14 minutes of "Like and subscribe to my channel", "see our patreon here ...", "join us on discord...", "today's sponsor is: ...", jokes, side-tracks, history of, explaining basic concepts that should really just be a reference to another video.
@@soylentgreenb add is a thing too!
I know I’m on a good vid if I don’t start scrolling… I’m typing this with playback speed at 1.5, less than one minute in… now I gotta back up
15 minutes is all you got? Lol
Another good thing the hollow sections have is that you can make composite columns with them. Helps in the workability when you pour the concrete in. Also, it has more resistance than a normal hollow section due to the interaction of the hollow section and the concrete column, meaning it can result in having even longer span of elements than with a steel section alone.
Thank you for this interesting and informative video. Three other properties occur to me:
Crushing (eg elephant sits on a tube)
Crippling - relates to length/stiffness in and end-load situation (eg elephant sits on a platform atop a long tube)
Impact strength (eg car veers off the road and hits a structural member, or any day in a war situation)
To answer why these are not included; crushing is better known as the compressive strength and, ignoring buckling, it is directly related to the area of the section; crippling is better known as global buckling which is addressed in the video; and impact will relate to local buckling and material properties, assuming we are only using steel, then it is also addressed in the video. Have a look into global and local buckling then I’m sure you’ll have a better understanding how those concepts are related
@@WillDiggy1 Thank you, Sir,
such an outstanding analysis!
I am an Engineer.I covered,Strength of Materials,Mechanical Systems,Engineering Design and Mechanical Technology.
Beam Shapes and Hollow Section Profiles as stated in the
video,depend on many factors.
Nowadays there are many newer materials in existence ,compared
to when I started my Higher Education and Training in Engineering.
Composites and Nano-Materials are a few.
Came thinking I’d get a meme list, stayed for a bunch of engineering jargon and math I don’t understand.
9/10 stars, good video.
I've worked with U Channel beams, and for their weight, they got quite good bending strength. Certeinly, a good option for longe free span structures without much torsion loads... Anyway. Nice video man.
Thanks for sharing!
@makermartin10 - How about U-Channels attached to Tubular Cores? Or Square Tubes fitted with Round Types, internally?
Adhesive Bonding, Welding (via Rosette Welds from the Square Tube in Circular Openings, not too big), or Bolting Through, to transfer and Share Loads!
@9:13 those are not structural pipes but Fire Protection. the "victaulic" grooved couplings that you call "collars" are only meant to join the pipe to convey fluid not add reinforcement to the building
I wish I had this in school. Quick and efficient concepts make long calculations way easier.
My opinion:
Circular hollow (but not too thin wall) for torsion and for carrying fluids (literally a pipe)
Circular solid for dynamic crankshafts (like transmission and engine shafts)
Square hollow for smallish columns
H-beam for large columns (possibly embedded into a concrete pillar)
I-beam for any type of uniaxial bending about x-axis (such as a beam supporting only weight of gravity)
I-beam for columns, if braced in the y-axis
Angles for connecting other beams together
Rectangular solid for any type of wood (this is also the only type available for wood generally)
Channels for embedding needs
T-sections are more or less outclassed by I-beams for most applications (also calculating the moment of inertia for T-sections is a huge pain in the ass)
Neat rating scheme and animations! Keep up the great videos
Thanks!
Stumbled across your video, you earned my subscription!
Thank you, and welcome aboard!
I am building a hanging bar and was going to use angles for them, after watching this I will be using hollow rectangular pipes.
Thanks !!!
It’s amazing how some people can take something so natural and common sensical as balance and strength of an object and complicate the Hell out of it with unnecessarily complex or obscure words, diagrams and formulae, for what should come as intuitive awareness or knowledge to others. I guess not everyone is cut out for engineering.
Hahaha cut out
Excellent video, this explains the pros/cons of structural shapes much better than conventional resources and curriculum. The school of TH-cam is putting colleges in their place, they better embrace it and adapt or they'll become outdated.
I'm sure there's better media for today's engineering students but i would have loved this video back in the day when i was in school.
Hah, yes it would have been nice for us to know this back in school too.
one thing, which i wanted to see was price comparison - probably the most important of all, seriously.
You help us do it right the first time. Thank you.
Excellent presentation. That plots are really helpful and easy to understand the differences between steel sections.
Glad you enjoyed it!
I often see elliptical tubing used for things like motorcycle and aviation framing/support elements... in talking about wood framing, sheathing, with adhesives, seems to offer a big advantage in making a kind of 'tubular', or even, monocoque, structure, with much added stability.
Thanks for an interesting presentation, and interesting graphical/numerical scoring method(s).
I had forgotten about elliptical tubing. It seems to combine the properties of circular pipe with the properties of hollow rectangular tubes.
I first saw them being used for reducing weight on bicycle frames while increasing bend resistance in the commonly loaded direction.
This is very interesting !
One of my favorite courses was "Strength of Materials".
We got into some of this but not with the depth that you included.
Channels and angles also deflect rotationally under bending, especially when cantilevered. They make poor beams when the load is placed perpendicular to the flanges. As one commenter notes below they walk off access to the direction of the load. Triangular shapes are actually better in bending than square shapes of equal area and, when extruded, extra material can be placed at the corners to maximize section modulus. Unintuitively, symmetry is good. Connectivity is of course horrible. I would be interested to see your analysis of solid and hollow triangular sections.
Very good point about rotational deflection under bending. In fact, we happen to be developing our next video on this very topic!
Noted on your comment about triangular sections. We'll look into this more and see if we come up with anything.
Cheers!
Log cabins with almost round solid circles (flat at top and bottom if I don't recall wrong) would have been lovely to see here even if it's not a modern approach.
Curved wood was also used back in the day for certain roles, think of the wood where a branch leaves the tree or in the roots etc.
I'm no expert on that kind of things, but I'd love to learn more.
Nice video! I liked the side-by-side rankings of the different shapes. Another great video would be if you delved more into the bracing, connection, or other practices that improve on the relative weaknesses on each type of section.
Very good video stress wise. My only real disagreement is with the workability values. Good Job!
It can be noted that the Double-T Precast concrete beams mentioned at @11:41 which are commonly used in parking garages and bridge decks are structurally somewhat different than simple metal t-shapes as the required included reinforcement is nearly always pre and/or post-tensioned steel rods and/or cables. this significantly increases the bending resistance of the complete part.
Very well done. I'd be interest in a follow up video where multiple shapes are combined. adding an angle to a flat surface creating a triangle, and combining triangles to make a honeycomb.
you have to recalculate the moment of inertia to determine flexural limits.
Great presentation! Thanks for taking the time to explain it.
Nice job. Clear explanations and almost no math!
Excellent video- teaches you how to think about structural shapes, not what to think.
I am building a full-length (19.5 ft) pipe rack for a pickup truck. The longitudinal pipe (back bumper to front bumper) needs to be strong enough to be able to haul heavy cargo. I have posed the question to friends about what size square tubing should be used and I have received several confusing explanations about this design. Keep in mind that I have to keep it as lightweight as possible. The first method is to use a single 2x1 thin-walled square tube to run the length of the rack. The second method is to use "two" 1x1 thin-walled square tubes either welded together or bolted together in order to make a final 2x1 length. I was told that the more angles that you have on a span the stronger the span will be. The other thought is that a consistent uniform design (2x1) will be stronger. Which would you prefer and why? Thanks.
I have never studied this before, this been in my mind for long time
Cool video, I like your rating method! The only thing is that the transverse stiffener shown at 5:03 does not improve torsional resistance, it improves local web buckling. Torsional stiffeners would need to run down the axis of the beam closing the section for the entire length of the beam loaded with the torque. Great video otherwise!
Thank you for this great informational video. Keep up the good work. 👍
Cheers, will do!
Thanks for the video! Have been interested in this topic but didn’t know where to start.
Glad it was helpful!
Oftentimes, these shapes can be used in conjunction with one another to strengthen areas in which one shape is weak. Thank you for sharing this video.
Thank you for makign this video, really helpful for some engineering students who ae going to take the final exam in less than 2 weeks
The voice is so soothing, I would play it for children to fall asleep. But the content is very interesting.
I am constructing a small home on 1500 squarefeet plot. Traditionally, constructions in my area is done by raising 12 RCC pillars (columns) on the plot before pouring concrete to form a flat roof. From this roof and above, residential quarters begin where each floor raised above the column is considered independent residential units. I, on the other hand, prefer a mezzanine construction on my 1500 squarefeet area. Purely for personal use. So my priorities are lightweight and economical materials versus the traditional RCC columns that need steel bars concrete mix. Would I be wrong if I prefer H or I beams instead of traditional RCC column for framing the structure to lessen the concrete use? Would it be economical and would I be able to achieve better structural strength than RCC columns?
Great video! Do you have a video for which shape (or material, including wood) works best for certain spans? Thanks for your channel.
Since the comparisons were based on equal cross sectional area (in other words for a given material the same weight per length) the analysis tended to obscure the strength per weight. If building something like a race car chassis where weight matters a lot, it's impossible to beat round tube. But cutting it to make joints does require special equipment and skills. You can buy jigs that use just a hand drill and hole saw, but getting the measurements and angles right takes thinking and attention. Square tube is a second place. The weight is higher for the same strength but welding joints is as easy as it gets. A handheld band saw will allow you to make just about any joint between two square tubes that you can imagine. I was surprised that he rated workability so low for square tube. But he was looking at bolted connections more than welded. It's just that among DIYers the people needed to choose different steel shapes are probably mostly people that can weld
Instead of surrounding rebars with concrete, how about filling hollow pipes with concrete. Or fill with resin for smaller structures like furniture. This would reduce the chance of buckling since the internal fillers are solid and resist compression.
those are called composite sections. They are in the AISC manual.
I'm doing that for a crane I'm building this weekend
when bending angle over a long span, it's interesting because it will dive or climb in the axis that you aren't bending and will have to compensate for
Yes, you are correct there. In fact, we happen to be developing our next video on this very topic!
I’m a software engineer who makes web apps. Why the hell am I binge watching these videos?
How does a triangular tube compare? Or a solid one? Are they viable? Or even used for that matter?
Helpful video, thanks. I would say that workability depends a lot on the tools available for a given material and shape. Having the appropriate tools can make the workability much easier. And not having them can make anything difficult. All that is to say I would not have given workability as much weight as it is given. Or, in practice, weight it in light of the available resources.
Yeah, workability is a bit of a strange category to me.
I also don't see how I-beams are more workable than hollow rectangular tubes. If you have to trim out an I-beam, it gets pretty awkward for where to attach your stuff. But trimming out a hollow rectangular tube wouldn't be that hard IMO.
Where was all this when I was in school, great job
It completely depends on what you're wanting it to do.
Anyone that knows what "area moment" and "section modulus" are already knows the answers to these questions. Those that don't are not being helped by throwing in words that are not familiar.
Fair video, i would have liked in the conclusion to highlight framing outside of wooden construction with the correct fastening and alignment many flaws in each element can be reduced
I’ve used almost all of those at my work at the Utah Water Research Laboratory making models for the customers. There’s a lot that goes into model building that’s very similar to a lot of trades.
Imagine that. A Young in Utah.
I don't mean any disrespect man, just that I know way too many Young's.
Very clear information explained. Thanks
well explained, understandable
Thanks for this video. I found out why something that I knew was true by intuition is that way.
Great one.
what about a square with a cross in it?
kinda like an horizontal i and a vertical i merged together.
as a Civil Engineer i would say your analysis was good.
An illiterate coward claiming to be an engineer?
I would say it is a very well informed purely scholarly approach with some notable gaps in real world knowledge and experience. For example the double T bridge sections he described. Those are generally post tensioned with cables for the strength of the structure rather than relying on rebar that is only contained in each individual section and doesn’t transfer load. He also ignored how the shapes he discussed are used as part of a larger system and the loading in each member is influenced by other members. And the shapes he deems less worthy are great at transferring smaller loads between more larger examples of ideal shapes.
Here in the Philippines we call it pipe instead of circular hollow, Square pipe for rectangular hollow, round bar for circular solid and square bar for rectangular solid.
Hi Jezreel,
Very interesting terminology--square pipe!
All the rest of the terms are the same as we generally use in Canada.
For this video we used the terminology circular hollow and circular solid to aid parallelism in our verbiage, but we would normally just call them pipes.
Excellent overview. Like the rating system. I weld pipe. Don't like the unsafe person cutting steel at 10:33. No glove, no cutting wheel guard is a bad idea.
There are many structural shapes because different loads required difference design considerations. No one is BEST for all things, but each has it's place. There are no winners or losers.
When you position material furthest from the centre, and then make a cellular character within the outer wall, with cross ties to reduce buckling risk, congratulations, you have invented a stem of grass, or bamboo.
If you're clocking a burglar over the head with a steel member, I've found just about any of these geometries to suffice.
Answer: It depends on the application.
Wish I had videos like this when I was training to be an engineer 45 years ago.
You correctly inform us that we need to select our section acording to the application. Therefore there can not be a clear winner.
You say the torsion in an I beam depends on its 'J'. If you mean 'J' as it is usually understod, IE Ix+Iy then you are wrong. It depends on its 'K' which is much less. I recomment Roarks formulae for stress and strain for a better understanding.
'U' or 'C' sections have a further disadvantage to the doubly symetric 'I' in that they have a shear centre outside of the section which can easily lead to combined bending and torsion when loaded with simple shear.
From a practical point of view, closed sections are difficult to treat against corrosion and equally difficult to inspect, unless of course you can get inside it eg the leg of an oil rig.
Hi again Emma, by J we mean the ''torsional constant J'' and not the polar moment of inertia or the summation of the moment of inertia about the x and y axes. Check out Chapter 3.10 in Mechanics of Materials by Gere, the twisting of noncircular prismatic shafts and the torsional constant are explained there. The factor K in ''Roark's formulae for stress and strain'' is the same factor that Gere calls J and is the torsional constant. In regards to the shear center, we agree that this is an important point that is worth mentioning. Maybe we can do another video only on the shear center of sections in a future video. Thanks for the good discussion as always.
@@TheEngineeringHub I am reassured. Being aware of different definitions is important, particularly when presenting forbeginners.
Glad to help.
You got a like how some of this engineered wood products mimic the cross-section of an I-beam. You have two two by fours with a groove cut in them with a jointer of plywood. The end up being lighter than a typical Lumber member but you have a bit more convenience on putting holes through for plumbing and electrical for example
That chart/diagram was really helpful
Paintability (e.g. corrosion protection/inspection) is a big disadvantage to closed, hollow sections. Could be baked into the Workability metric, but could be a game-changer alone.
On the other hand, the structure could be designed so that the inside is sealed up so it doesn’t matter. This is most likely the case anyways when the ends need to be welded up.
I would be interested in an analysis of torsion boxes.
Exactly what I was looking for!
Good overview!!! An error at 5:02: Those stiffeners will help nothing against torsion!!! On should add them on the sides over the length of the I-beam (to give it a tube shape).
I have always wondered about triangular shapes like trusses. Triangles are geometrically rigid by definition. I can see them buckling unless you put in a compensating truss. Your thoughts?
Trusst in triangle
Also what about a t beam virtually a reverse triangle (3 points of contact)
2:00 "I.E. Stiffness" I see what you did there
hahhaha finally someone picked up on that !! It's been a year
I am stricken by the extent of variety in shapes chosen by the state highway agencies in various American states for the identical task: posts for small highway signage. Right off the top of my head, I can think of various states that use perforated hat channel, perforated square hollow, circular hollow, and square solid (wood). Surely each has advantages and disadvantages, but one would think that more consensus would have developed as to which is the best value over the long term.
Sir, how can I prevent cracks in non-loading partition walls due to deflected steel structural beams' interaction?
Great video... maybe explain how you get to those numbers next time...
Very good summary! Thanks!
Glad it was helpful!
6:27 - - *THIN PLATES BUCKLING UNDER STRESS*
6:58 - - *Rectangular + square sections can be OPTIMIZED by creating hollow sections (or tubes)*
13:00 - - How would a *hexagonal* hollow cell/member rate on this score-system?
Tee angle channel is the best
NICE AND CONCISE ! angles actually of 2 types the between 2 objects that uv shown and the surface angle. the 2nd 1 shows much much greter bending resistnce
Amazing animations man great video
the answer is; It depends on what you're trying to build. If it's something, like a simple garden shed, then maybe use one of those L shaped pieces in the corner for some support.
What about tension and compression? And the planes of tension/compression. T shape, round, square, and angle are used alot in truss systems. Analysts and design was fun, i became to see the formulas in the 3d spaces.
I was going to make a very similar comment. Angles are used in tension on the bottom cord of many flat roof trusses. And welded connections can not be ignored when discussing workability of structural steel.
As another commenter pointed out, many times the decision comes down to cold hard cash. What is the cheapest way to meet the requirements without exceeding them. Many times designers create impossible conditions that can’t be fabricated in the real world. So I am not sure how much I trust them to care about what the constructors go through.
Several years ago at work, we needed to install some bollards. My suggestion was to slip a square, I, or triangle tube into a circular tube or a circular tube into a square tube to increase bend resistance. What are your thoughts on combining shapes looking just at the factor of bend strength?
Concrete poured into a circular tube
Bollards are designed to stop smart people and slow down idiots. If bollards were made stronger the risk of injury would increase. Cars have crumple zones for a reason.
Oh and a single thin wall pile filled with concrete is cheaper than the fancy strong design.
@@beerious8392 That was what we replaced. The pipe (6" diameter) bends causing the concrete to fracture then the pipe bends too easily.
Sorry, extremely valuable and sensitive equipment that MUST work at all times. After getting called out a few times at 2AM when it was raining sideways to repair the damage caused by some dimwitted moron that couldn't control his vehicle - I really don't care HOW damaged the vehicle OR injured the dimwitted retard gets.
I Beam shape is what is used for combustion engine piston rods / Gas and Diesel... for that reason.
Can you make video on structural members used in brigdes like about rectangular column, cylindrical column,why they have fillet in some parts,why they have low depth at ends but high at centres in beams etc.
Thanks for the explanations! I wonder how a triangle would perform in each category.
Hexagons are the bestagons! /shrug
Aside from the complexity of manufacture, the flat faces would make attachments easy, as long as you make allowances for the work face possibly being 30 degrees from your desired orientation.
@@MonkeyJedi99 yes, I'm aware of shortcomings in manufacture and connection to other structures, but since a triangle is considered a pretty strong structure, I'd really like to know how it compares to the other shapes in performance.
nice video. im not going into mechanics or anything but it was very entertaining.
as always, depends on the requirements. they are there for a reason
agreed! Thanks for the comment John
Very clear video !
Every structure has its appropriate application
and yet a huge amount of frames (equipment bases and adjunct support n mounting) and small structures are fabricated with angle iron in the US
I think an IV and could be the strongest. In eighth grade we had a science project where we had to build a bridge out of popsicle sticks we had a certain number of popsicle sticks and a specific amount of glue we were able to use. It was a competition throughout the whole school. I won that year my bridge held a 145 pound girl without breaking we had to use this girl because we ran out of weights to put on it.