Bolts in both in and out of plane bending

[@khtan79]

Thank you so much for this video! This world needs more real engineers with proper knowledge.

[@mikebather]

Yes and I also think that this world needs more engineers who are not old, white and male!

[@michaelan9688]

@@mikebather diversity is great but don't guilt yourself! By making this knowledge freely available to everyone you are already a part of the solution! You should be proud of yourself sir!!

[@gordongrover4065]

Short and thorough. Explanation with the diagrams has topped it off.

[@jrhumberto]

Mike, just want to congratulate you on this initiative. The teaching methodology used is fantastic and the videos are well presented. Excellent work that should be recognized. Well done.

[@mikebather]

Thank you.

[@DOTA2MAJISTRATE]

really good, your work is really excellent, you sounded like a very gentle and soft person but you possess great knowledge

[@jamesmaher6461]

Really interesting clip. Working in a structural steel fabrication shop as a QC and i find this very interesting. We fabricated cantilever signs before so i know this exact base plate..

[@mairajhabib9754]

Hi Mike, just came across your worthwhile video. Thanks for uploading numerical to make easy to understand for Engineering fraternity. Would love to see your videos in future as well. Pl keep on do this.

[@stevetari3990]

Wow..am so happy i found your Videos. My finals are just around the corner and am struggling with my structures course which basically covers most of what is covered in your videos. I just wan to thank you for sharing this on you tube. I pray that our Good Lord will continue to grant his blessings upon you my friend.!!Cheers Steve

[@mikebather]

Thanks, good luck in your finals.

[@robertoreyes8577]

Great video! This is my engineering nugget of the day.

[@vschary]

Hi mike , thanks a lot for these videos. You explain very nicely. Please post more videos. Thanks again.

[@maverickw3963]

Very informative and easy to digest. Does the same principle apply to the CHS instead of RHS? Ie will the center of rotation be to one side?

[@mikebather]

Hi Maverick W, that is a good question. Yes, for out of plane bending, there must be an axis around which rotation takes place. In an RHS section we choose the centre line of one wall - so this is fairly straightforward. For a CHS section, it is a little more complicated. Looking at this in a slightly simplified way, we just need to make sure that there is enough steel acting in compression in the curving wall of the CHS (so that the compression stresses are not too high) and our axis of rotation needs to be drawn through the centroid of that steel in compression. This is quite hard to find, but you could easily make an estimate that is likely to be near enough for preliminary modelling hand calcs and to check the output of software. I hope that this helps, Mike

[@guislowhand]

Thank you so much for taking your time and recording such a great video.

[@musamahomed]

Hi Mike, really well explained. Just a quick question if you don't mind, Is there a need to check prying action and how would you go about it?

[@mikebather]

Hi Musa Mahomed, thanks for your comment and question. Good point. I have focussed on just working out the forces in the bolts - rather than designing them. To do this, it is likely that you would need to choose a code of practice and this is where you would begin to consider prying etc. I believe that some codes include a 'hidden' allowance for prying and others require the designer to consider it specifically. It depends. Hope this helps, Mike

[@musamahomed]

@@mikebather thank you for your response.

[@MuhammadImran-ul5ww]

Dear sir you are the Hero Kindly also upload one lecture for gantry crane bolts 👌😍😍

[@ajazmahemoodsayyed4122]

Amazing sir

[@jamesardinez9923]

Hi there, Just a quick question Sir, Where did you get the direct shear of 80 KN divided by the number of bolts?

[@tinad5965]

You can be a excellent structural engineer and teacher.

[@SpaDerola]

could you take the moment position in the centre and then still do sum of the y squared but subtract the negative y distances? I assume you would get the same result?

[@mikebather]

Hi Ben, I am not quite sure that I understand your suggestion. Usually, it does not really matter where you take moments - you should still be able to work through to an answer as long as you are careful. For this connection, I have just tried to show the quickest and most straightforward way to get to an answer, Mike

[@SpaDerola]

@@mikebather sorry difficult to explain without a drawing. Thanks for the video

[@vaibhavwagh8782]

Sir i didn't understand thew point of rotation why its in the center of flange....?

[@mikebather]

Hi vaibhawagh8782, that’s a good question. Yes, the centre of rotation (for bending about one of the two axes of the RHS column) is taken to be the centre line of one wall. Imagine a solid brick on your desk. Imagine pushing it horizontally until it falls over. First, tension develops on one edge of the bottom face (at the base of the face that you are pushing), then that edge of the brick starts to lift up and so all of the vertical load of the brick is transferred to the desk via the opposite edge. This is the only point of contact and this is the centre of rotation. The brick rotates around this edge. The steel RHS acts in a similar way. I hope this helps, Mike

[@joker75369]

This entire video saves my life. I just want to thank you. However, I was keep wondering where the formula Ft = My/y^2 comes from? And what does that y^2 mean?

[@PTEtipsntricks]

at 12:00 he calculates X2+y2 whose units are mm2 but he then he says its momet of inertia with mm4 units? How

[@mikebather]

It is a little hard to explain this in words, but the force in any one bolt can be found by using similar triangles. It is assumed that the force in each bolt is directly proportional to its distance from the point of rotation and its position with regard to the other bolts in tension. I realise that these words are not much explanation but I hope they help a bit.

[@doomslayer4276]

Hi thanks for the video ! I've got a question In plane bending = Torsion Out of the plane bending = Bending about minor axes and major axis Is my above statement right ?

[@mikebather]

Hi doomslayer, what you are saying makes sense for an endplate fixed to the cut end of beam or column attached to a support with the endplate at 90 degrees to the longitudinal axis of the beam or column, Mike

[@shivukuderu]

Great explanation! Thanks

[@sardarmokri2398]

If we have a circular section how do you determine the center of rotation?

[@mikebather]

Great question, this is a lot trickier than for a rectangular section or for an open section bending about its strong axis. What follows is a suggested way of thinking about this. Other engineers may have different opinions. Remember that you can work out the compressive force in the flange of a section in a moment connection. Well, this compressive force must be transmitted between the member in bending to its endplate and then to the supporting member. At each point of transfer there must be sufficient weld or metal to transfer the compressive forces. So roughly think about sizing the weld to carry this force and then consider what area of metal is needed to carry the force (in bearing). Once you know this area you can estimate the area of the circular section needed to carry this force and find its centroid. This could then be taken as the stiff point around which rotation takes place. Please remember that these calculations are an approximation of the way that steel connections behave, only considering elastic behaviour, in reality, things are more complex. However, there is always a balance between time spent working these things out and getting an exact answer. Hope this helps, Mike

[@drussnitis8112]

13:17 Are we assuming the polar moment of inertia is in units of mm2? Since the calculation works out in units of kN rather than kN/mm2?

[@drussnitis8112]

Taking this one step further to bolt design.... if we ignore the area of the bolt, and work with polar moment of inertia mm2, can the resultant force simply be checked against the max shear strength of the bolt to confirm adequacy of the bolt?

[@zeeshankhanpathan7322]

Thank you very much sir for giving us such a good explanation. I would like to learn more from you. Can you please take up an example regarding the base connection design of a mono pole(height may be 20m or 30m) i would like to learn more accurately working out its base plate design and anchor bolt design by working out the tension and compression in bolts as well as in base plate. this would help me a lot.. i would like to thank you in advance.i will be waiting for your video upload.

[@mikebather]

Hi zeeshankhan pathan, thanks for your comments and suggestion. I am working on some different videos at the moment but will try to remember your idea for the future. In the meantime, many engineers in the UK make use of the Sign Structures Guide (www.theihe.org/wp-content/uploads/2013/08/SignStructuresGuide2010.pdf)

[@zeeshankhanpathan7322]

+Mike Bather thank you sir for considering my request. And I will go through your given guidelines.

[@tzachus]

it will be great if u explain with bolt to choose. is there contue to the vidio?

[@randomness2376]

Hi Mike! This maybe a trivial question but is there a design method for the edge distance between the bolt and the base plate? If the edge plate edge distance from the bolt is not adequate, it could fail right? What is the failure mechanism?

[@mikebather]

Hi randomness2376, you are perfectly right. The edge distance of bolts is really important; as are the bolt spacings and the end distances. If these distances are not right, it is possible for the plate to fail by tearing - this could be local or block shear failure. In this calculation, although the force in the bolts is found, the design of the bolts (and their setting out) is omitted. This would be the next job for an engineer. Hope this helps, Mike

[@abdullahshaikhengineer]

its good

[@jamesmaher6461]

Keep it up by the way..👍👍👍

[@samkirubakaran8931]

Speak louder Cant hear most of what you are saying I had to put this video in a speaker to hear it With that said i have finally understood what is inplane and outplane moment Thank you

[@edumadzequansah]

Something beautifully for free and you are complaining - Go and buy a book and learn it please. All u could do was complain and not appreciate.

[@sardarmokri2398]

Hi, Could you please tell me how you concluded that the center of rotation is the center of the wall of the RHS? Maybe it is in the middle of section.

[@mikebather]

Great question. Firstly, and least convincingly, this is the approach traditionally assumed in design offices for relatively flexible endplates. Secondly, you could pick up a brick and stand facing a wall, place the brick flat against the wall and rotate it (moving the top of the brick towards you and the bottom away from you). No matter how hard that you press the brick into the wall, the top moves away from it and the brick pivots around the bottom corner which simply presses against the wall. This is because it is a stiff point and does not 'give' or deform. A steel beam is similar, the bottom flange is a stiff point around which it inevitably rotates. I hope that this helps, Mike

[@cbassich1]

Excellent- thanks so much!

[@constructgeek3808]

Very helpful thank you Sir

[@RayhanNuman]

Could you please suggest any book or reference to study this type of problem?

[@mikebather]

Hi RayhanNuman, I am sorry to say that I don't know of a textbook that covers this topic well, Mike

[@MrBulbul25]

How did you get the in plane and out of plane moment? what is the load and the lever arm?

[@mikebather]

Hi Nabeel, in this example I have just plucked the in and out of plane moments from the air. In reality, an engineer would have to calculate these considering wind loads and the weight of the signboard. Sorry, but I cannot fit everything into such a short video! Mike

[@tzachus]

sory y did calculate i just now sow the all video

[@tzachus]

pls corect me if im rong but you forgat to colculate the tourke moment of the wind that miens that there is ander moment that cost the sing to rottet around is exis.

[@MrBulbul25]

Hi Sir, The total tension force =668.2 KN not 666.2 KN

[@mikebather]

Hi again Nabeel, you are perfectly correct. I will add a comment to say as much, thanks, Mike

[@PTEtipsntricks]

at 12:00 he calculates X2+y2 whose units are mm2 but he then he says its momet of inertia with mm4 units? How

[@mikebather]

Good spot, this is an error (I think that I was rushing to complete this calculation to avoid over-running the time limit set by You Tube). The polar moment of inertia calculation can be used to combine areas (such as cross sectional areas of bolts with units square mm). So you can assume that each bolt has an area of 1 square mm and then the final units become mm4. It would have been better to leave the units as mm2.