Super useful po na info. salamat; ganito gagawin ko sa pag install ng cpurlins ng own house ko under construction pa. Ako lang po gagawa #fitter/welder
Thanks Sir, very well explanation : siguro maganda kasi placement ng cleat angle pag naka open upward :) suggestion lang sir baka pwede One same sample design videos series (from A-Z)..salamat sir. 👏
Hi Sir, Please respect comment. I’m happy that despite your busy life you still have time and willingness to share your knowledge. In your presentation you only consider the resistance due to the gravity load which is already known, constant and can be design accurately. Why not consider the wind load that occurs in actual scenario which is not constant and may come from the opposite direction. What if wind load in opposite direction is greater than the gravity load in your presentation, Can I turn my purlin’s opening pointing up? Is placing the purlin’s direction along the roof slope will not cause instability? And is detailing with C purlin’s opening pointing up for OBO, acceptable professionally ? Thanks for your response in advance:-)
Great question! However, wind load are transient meaning not always there. It is "gust" that counts not the regular wind that happens everyday. ex., when the wind blows(gust) roof sheets will play as a diaphragm because it is a system, purlin and roof sheets are secured with each other firmly. If you try to figure-out, the only force from the wind that may cause an upward force is tangential component which seems negligible especially if the roof is stiff right? and will be absorbed by roof sheets because of the system that I mentioned. Theoretically we don't treat it that way but in real life that's how it goes Of course, as a professional we do respect other people's opinion, so it is up to them on what they think is good. We call it "engineering judgement" Thank you for your comment
@@jsdesign_engineeringtv3633 Thank you very much Sir for your response! I tried to copy the paper C-purlin in your presentation and assumed that a very strong wind comes normal to the roof, actually I blew it with an electric fan. The paper C-purlin with opening pointing down bent easily compared to paper C-purlin with opening pointing up. It makes me realized that I should install the purlin with the opening pointing up since I can make sure the purlin to resist gravity load but not wind load. Also, installation wise, it would be more easier to put the purlin with opening pointing up with the cleat or stopper below it rather than above it. In my opinion, since installation of the purlin with opening pointing up is acceptable professionally, I will choose it. Your video were really very helpful to us, Again thank you very much:-)
@@PROBINYERO if you're in parts of the world like in the US where you have tornadoes, maybe wind load is a concern, especially when roofs are lifted upwards. But for our case, typhoons/hurricanes deliver wind-load sidewards and downwards. And as sir JS already discussed, windload doesn't blow directly to the purlins, rather it blows to the roof system as a diaphragm, and then transfers the force down to the purlins. When an engineer speaks with numbers, it's plain truth. Numbers don't lie. And i tried the paper purlin also :)
@@BC-hb5fl Hi Benjamin Sir thanks for your thoughts . It is true that wind load has no significant effect if you are designing a whole building considering different load combination because oftentimes gravity loads govern, sometimes seismic, however I disagree that in our case "Philippines" that typhoon/hurricanes deliver wind-load sidewards and downwards, it is always either way. In fact, if you will check NSCP 2015 figure 207E.5-1 negative pressure is always higher than the positive pressure. Thus, if you will be designing a purlin alone it is the uplift pressure that governs. Also, tornadoes were already seen in the Philippines. Well this is only my opinion. As, Sir JS said it's up to us. Thanks again:-)
I'm sorry but I am not in agreement with your investigation procedure. As we all know, section moment of inertia is a measure of flexural resistance about principal axis. This means that in either orientation, the location of principal axis is unchanged so transferring the axis for calculation purposes is not meaningful. Though neutral axis plays an important role in the design and its distance from the outermost point is different in each orientation, the flexural performance is pratically same. I would rather consider the idea of local buckling as the deciding factor why C section is oriented in a particular manner. Flange local buckling when under compression is prevented when lateral support is provided. In this particular case, the web component can provide lateral support to the flange when oriented in a manner that the web component is also under compression. When the C purlin is only subjected to gravity loads, it is therefore best to orient it as you presented to prevent local bucking. Happy New Year to everyone!!!
Agree. Moment of inertia is the same no matter how you orient the purlins (computation shown regarding 4x difference is misleading). Purlins should be pointing upward (i.e. against the slope) to minimize eccentricity of load from the shear center, hence less torsion
Good day po engr.,tanong ko lang po bukod sa not economical,ano pong disadvantage or magging problem kapag below 1.5m clear space between two trusses po.salamat
Ang pinakatamang orientation ay yung option C na hindi niyo po binanggit Engr....nakataob....pinakamatibay, madaling iinstall, matibid dahil wala ng bracket... Kahit hindi na po kayo nagcompute Engr kasi kita naman sa section na pinakamalakas yung I.xo Try niyo pong pataob tapos gawin niyo po yung paper sample niyo at yung inertia.... transfer mo.of inertia hindi narin applicable kasi po kahit baliktarin same lang.
Nope. Mali po ang nakataob..although ang nacompute dito is moment of intertia with respect sa Y-axis..mas malakas parin ang load with respect sa x-axis kaya nakatayo parin dapat. Mali yung ganyang practice. Yes madali ang installation at makakatipid. Pero di mo namamaximize yung strength ng C-Purlins. Nakatipid ka nga sa installation pero pagdating ng bagyo baklas naman lahat.
Tanong ko lang po bakit po yung iba ang binibigay na explaination is about shear center ? At yung sag rod po ba ay may part din sa kung anong orientation ng C-purlins ? Thank you po sir.
dito sa tacloban may kilala akong architect na baliktad ang utos nya sa foreman na paglalagay ng c purlins, buti na lang nakita ko and i rectify it, upon knowing that the architect has a psychological problems....sa sobrang talino bumigay ang utak....how to complain those kind of architect sir...para matanggalan ng Lisensya...
bakit ng nagsample ung gumagawa samin napipi ung purlins pag downward kc nga pabab ang ang bigat hindi nmn pataas ang bagsak ano ba yun? baliktad ata saka dba masmatibay ung upward tapos my support pa ng angular hindi sya napipi pag may umalyat mag aayos ng bubong kesa ng downward napipi kc naka slide nga sya pababa ang tendency pahulog ang ang bubong hindi pataas
@@jsdesign_engineeringtv3633ah, eh sa panahon po ngayon mostly prefer ng karamihan is rafter design na ng roof. Same lang po ang application ng c-purlin downward method installation kahit rafter design lang.?
There is no correct distance actually I shall say to use the word "ideal distance" Normally it dictates by column spacing where we place truss ends, but in case of too far spacing example 6m apart, that is too long for purlins length right? I usually introduce two intermediate truss or rafter in between, therefore purlin length will down to 2meters If there is no option say 3m pwede mo lagyan ng sag rod to shorten unsupported length. Thanks
maraming salamat sir at ako ay naliwangan. karamihan kasi ay pina taob nila para raw makita agad ang tulo. tanong lang po may lakas ba si c-purlins kung pa taob ang lagay ni installer/fabriccator?
Sakin mas maganda tingnan pointing up at lagyan Ng sagrod sa gitna at every 60cm spacing cgoro matibay nayon pangit kasi tingnan yong pointing down Lalo na pag walang kisame Kong ayaw nyo maniwala tubular nalang gamitin😀
There is no straight answer, we knew c-purlins are light gauge channels, it comes in different gauges. Definitely kung gagamit ka ng thinner gauge it is cheap but less durable compare to a thicker gauge, kaya nga nag dedesign tayo para matibay at same time matipid However, in most cases, designers normally end-up using gauge 16 or 14 for low rise buildings, but like I said size and spacing will depend on it's length and load to be carried. Thanks
Hi sir tanong po..anu maganda or tamang gamit sa c purlins (bolts or welding) sa roofing po...?? Maraming salamat po...pa advise po kong okay po gumamit ng bolts??
I suggest to use bolt connection for light gauge channel (C-Purlin) kasi may possibility mabutas sa welding. However, may mga C-purlin na medyo makapal pwede rin mag weld connection ensure lang natin ma applayan ng primer right away para hindi mag start ang corrosion. Thanks
@@jsdesign_engineeringtv3633 sir thank you for your kindness reply kahit na busy ka pero nabigyan mo kmi ng advise,malaking tulong na po samin to,,maraming salamat po.more power and.GOD BLESS YOU..
Generally speaking, we need to know where the load is coming from, e.g. if the load is from top we should orient the section where the longer dimension is parallel to such load, in other words place it vertically. Thanks
mali! dapat pointing upward, dahil ang load ay vertical which is flowing to imaginary shear point, so, to resist the load flowing to shear point dapat pointing upward.
Mas mahina po ang section pag pointing downward..nakabase po ang lakas ng c purlin sa location ng shear center..Mas malakas po pag pointing up, buo ang shear flow unless kung pointing downward, half lang gagana ang shear flow ng section kaya mahina, ....thank you po and sorry po..
now I know. Thank you Sir
Thank you po sir,
malaking tulong po ito, napakalinaw ang explanation po ninyo. GOD BLESS YOU SIR.
Useful knowledge. Nice presentation. Cheers!
Salamat po engr. Naliwanagan na po ako.
Free online learning on CZcams. Thanks for sharing.
Very wonderful explanation.thank you so much sir 🙏🥰
sir maraming salamat nkakuha ako ng idea syo
Super useful po na info. salamat; ganito gagawin ko sa pag install ng cpurlins ng own house ko under construction pa. Ako lang po gagawa #fitter/welder
Thanks Sir, very well explanation : siguro maganda kasi placement ng cleat angle pag naka open upward :) suggestion lang sir baka pwede One same sample design videos series (from A-Z)..salamat sir. 👏
iba talaga pag theory ang pinagbasihan
try ko yan sir salamat sa pagpaliwanag ...
Hi Sir, Please respect comment. I’m happy that despite your
busy life you still have time and willingness to share your knowledge. In your
presentation you only consider the resistance due to the gravity load which is
already known, constant and can be design accurately. Why not consider the wind
load that occurs in actual scenario which is not constant and may come from the
opposite direction. What if wind load in opposite direction is greater than the
gravity load in your presentation, Can I turn my purlin’s opening pointing up? Is placing the purlin’s
direction along the roof slope will not cause instability? And is detailing
with C purlin’s opening pointing up for OBO, acceptable professionally ?
Thanks for your response in advance:-)
Great question! However, wind load are transient meaning not always there. It is "gust" that counts not the regular wind that happens everyday. ex., when the wind blows(gust) roof sheets will play as a diaphragm because it is a system, purlin and roof sheets are secured with each other firmly. If you try to figure-out, the only force from the wind that may cause an upward force is tangential component which seems negligible especially if the roof is stiff right? and will be absorbed by roof sheets because of the system that I mentioned. Theoretically we don't treat it that way but in real life that's how it goes Of course, as a professional we do respect other people's opinion, so it is up to them on what they think is good. We call it "engineering judgement" Thank you for your comment
@@jsdesign_engineeringtv3633 Thank you very much Sir for your response! I tried to copy the paper C-purlin in your presentation and assumed that a very strong wind comes normal to the roof, actually I blew it with an electric fan. The paper C-purlin with opening pointing down bent easily compared to paper C-purlin with opening pointing up. It makes me realized that I should install the purlin with the opening pointing up since I can make sure the purlin to resist gravity load but not wind load. Also, installation wise, it would be more easier to put the purlin with opening pointing up with the cleat or stopper below it rather than above it. In my opinion, since installation of the purlin with opening pointing up is acceptable professionally, I will choose it. Your video were really very helpful to us, Again thank you very much:-)
@@jsdesign_engineeringtv3633 this makes perfect sense po engr. Thank you for sharing your wisdom!
@@PROBINYERO if you're in parts of the world like in the US where you have tornadoes, maybe wind load is a concern, especially when roofs are lifted upwards. But for our case, typhoons/hurricanes deliver wind-load sidewards and downwards. And as sir JS already discussed, windload doesn't blow directly to the purlins, rather it blows to the roof system as a diaphragm, and then transfers the force down to the purlins.
When an engineer speaks with numbers, it's plain truth. Numbers don't lie. And i tried the paper purlin also :)
@@BC-hb5fl Hi Benjamin Sir thanks for your thoughts . It is true that wind load has no significant effect if you are designing a whole building considering different load combination because oftentimes gravity loads govern, sometimes seismic, however I disagree that in our case "Philippines" that typhoon/hurricanes deliver wind-load sidewards and downwards, it is always either way. In fact, if you will check NSCP 2015 figure 207E.5-1 negative pressure is always higher than the positive pressure. Thus, if you will be designing a purlin alone it is the uplift pressure that governs. Also, tornadoes were already seen in the Philippines. Well this is only my opinion. As, Sir JS said it's up to us. Thanks again:-)
Thank you sir. Yung iba po kasi ay based daw sa shear flow ng section kaya pointing upward
tama yan, dahil sa shear flow ng vertical load. ang paliwanag nya ay horizontal ang load which dapat vertical na tatama sa shear point
I'm sorry but I am not in agreement with your investigation procedure. As we all know, section moment of inertia is a measure of flexural resistance about principal axis. This means that in either orientation, the location of principal axis is unchanged so transferring the axis for calculation purposes is not meaningful. Though neutral axis plays an important role in the design and its distance from the outermost point is different in each orientation, the flexural performance is pratically same. I would rather consider the idea of local buckling as the deciding factor why C section is oriented in a particular manner. Flange local buckling when under compression is prevented when lateral support is provided. In this particular case, the web component can provide lateral support to the flange when oriented in a manner that the web component is also under compression. When the C purlin is only subjected to gravity loads, it is therefore best to orient it as you presented to prevent local bucking. Happy New Year to everyone!!!
Everybody's opinion are welcome, thanks for watching!
Agree. Moment of inertia is the same no matter how you orient the purlins (computation shown regarding 4x difference is misleading). Purlins should be pointing upward (i.e. against the slope) to minimize eccentricity of load from the shear center, hence less torsion
What is the formula to solve tangential load at normal load. Thanks
More in Structural Analysis si sir. Good for College in Civil Engineering not for everyone like Forman, steelman
Thank u sir very informative....
Magandang presintasyun.... subscribed ko na to
galing mo talaga sir
That's one is very informative
Good eve po sir. suggest ko lng po kung pwede po kayo mg gawa ng learning video how to compute trusses for roofing po sir thanks po :)
I'll try to make one sir. Please stay tune to my channel. thanks
@@jsdesign_engineeringtv3633 we'll wait sir.salamat ng marami
Galing 😮
Good day po engr.,tanong ko lang po bukod sa not economical,ano pong disadvantage or magging problem kapag below 1.5m clear space between two trusses po.salamat
Ang pinakatamang orientation ay yung option C na hindi niyo po binanggit Engr....nakataob....pinakamatibay, madaling iinstall, matibid dahil wala ng bracket...
Kahit hindi na po kayo nagcompute Engr kasi kita naman sa section na pinakamalakas yung I.xo
Try niyo pong pataob tapos gawin niyo po yung paper sample niyo at yung inertia....
transfer mo.of inertia hindi narin applicable kasi po kahit baliktarin same lang.
Nope. Mali po ang nakataob..although ang nacompute dito is moment of intertia with respect sa Y-axis..mas malakas parin ang load with respect sa x-axis kaya nakatayo parin dapat. Mali yung ganyang practice. Yes madali ang installation at makakatipid. Pero di mo namamaximize yung strength ng C-Purlins. Nakatipid ka nga sa installation pero pagdating ng bagyo baklas naman lahat.
@@HarielV.HernandoCE exagerated po ang example niyo sir pano niyo po masabi yun thank you po sa sagot
Sir sa practice ko po ang distance ko ng purlins to purlins oc about .6m to .8 m tama po b yun para di po lumundo ang bubong kung may mga repair
Tanong ko lang po bakit po yung iba ang binibigay na explaination is about shear center ?
At yung sag rod po ba ay may part din sa kung anong orientation ng C-purlins ? Thank you po sir.
I respect others' opinion. But anyway, sag rod will help keep purlins work as a sytem and shorten its unsupported length. Thanks
sir okay lang ba if ung malapit sa beam at pointing downward at Yung mejo ung gitna ay pointing upward para sa windload
Good job!
dito sa tacloban may kilala akong architect na baliktad ang utos nya sa foreman na paglalagay ng c purlins, buti na lang nakita ko and i rectify it, upon knowing that the architect has a psychological problems....sa sobrang talino bumigay ang utak....how to complain those kind of architect sir...para matanggalan ng Lisensya...
thank you po
Salmat sa pagturo.
Ayaw ko na sundin yong kasama ko.Halos mali lahat yong procedure nya.
bakit ng nagsample ung gumagawa samin napipi ung purlins pag downward kc nga pabab ang ang bigat hindi nmn pataas ang bagsak ano ba yun? baliktad ata saka dba masmatibay ung upward tapos my support pa ng angular hindi sya napipi pag may umalyat mag aayos ng bubong kesa ng downward napipi kc naka slide nga sya pababa ang tendency pahulog ang ang bubong hindi pataas
Same po ba yan sa pagdesign ng truss web member.?, kasi sa nakikita ko meron din downward and upward na design ng truss web member
No. Truss members should be treated as pure axial load. Thanks
@@jsdesign_engineeringtv3633ah, eh sa panahon po ngayon mostly prefer ng karamihan is rafter design na ng roof. Same lang po ang application ng c-purlin downward method installation kahit rafter design lang.?
What is the correct distance of every c purlins on trusses? Thanks
There is no correct distance actually
I shall say to use the word "ideal distance"
Normally it dictates by column spacing where we place truss ends, but in case of too far spacing example 6m apart, that is too long for purlins length right? I usually introduce two intermediate truss or rafter in between, therefore purlin length will down to 2meters
If there is no option say 3m pwede mo lagyan ng sag rod to shorten unsupported length. Thanks
Pataob po try nio ibend kht saang anggulo lumalaban lahat Ng side Nia
maraming salamat sir at ako ay naliwangan. karamihan kasi ay pina taob nila para raw makita agad ang tulo. tanong lang po may lakas ba si c-purlins kung pa taob ang lagay ni installer/fabriccator?
Theoretically maximum resistance of any section (not only C-purlin) is in stand position. Thanks
Use Tubular instead.
Ganyan ang approved ng (CSD)aramco
Hello sir new subs ano po ang tamang sukat sa distance ng purlings at trusses?thnaks and godbless
Paano po magandang pag dugtong? Salamat po.
Sakin mas maganda tingnan pointing up at lagyan Ng sagrod sa gitna at every 60cm spacing cgoro matibay nayon pangit kasi tingnan yong pointing down Lalo na pag walang kisame Kong ayaw nyo maniwala tubular nalang gamitin😀
Sir ano po ba ang ideal gamitin na c purlin i terms of patibayan?strengh i mean?
There is no straight answer, we knew c-purlins are light gauge channels, it comes in different gauges.
Definitely kung gagamit ka ng thinner gauge it is cheap but less durable compare to a thicker gauge, kaya nga nag dedesign tayo para matibay at same time matipid
However, in most cases, designers normally end-up using gauge 16 or 14 for low rise buildings, but like I said size and spacing will depend on it's length and load to be carried. Thanks
Sir Meron dn Ako nkikita na diskarte ng mga welder na nkadapa nman ung C-purlins. Question ko lang Po kung ok dn Po ba yon?
It depends, if they design that member to place it that way. Like I said in my video, different orientation will give different resistance. Thanks
@@jsdesign_engineeringtv3633 thank you sir for your good response.
Ayos
Hi sir tanong po..anu maganda or tamang gamit sa c purlins (bolts or welding) sa roofing po...?? Maraming salamat po...pa advise po kong okay po gumamit ng bolts??
I suggest to use bolt connection for light gauge channel (C-Purlin) kasi may possibility mabutas sa welding. However, may mga C-purlin na medyo makapal pwede rin mag weld connection ensure lang natin ma applayan ng primer right away para hindi mag start ang corrosion. Thanks
@@jsdesign_engineeringtv3633 sir thank you for your kindness reply kahit na busy ka pero nabigyan mo kmi ng advise,malaking tulong na po samin to,,maraming salamat po.more power and.GOD BLESS YOU..
Pwede ba blind Rivets Ang gamitin ko instead of screw?
Normally we use tek screw on roof-purlin connection if that is what you mean. Thanks
I mean Doon sa angular bracket para sa c pArlins Kung pwede po ba blind Rivets? Thank you sir
@@rodneyarrieta8816 I think it's a good idea as long as you make them firm. Thanks
Bakit yung iba sir tinataob nila ang c purlins
👍🏻👍🏻👍🏻
👍👍👍
Sir di maliwanag ang ilaw.
Good day po. Sir e paano po pag nakataob ang C purlins. mas malakas po ba? salamat po
Generally speaking, we need to know where the load is coming from, e.g. if the load is from top we should orient the section where the longer dimension is parallel to such load, in other words place it vertically. Thanks
Sakit sa ulo un ibang contractor ,kaya ipinina ulit ko un pointing upward ng c purlins,
Pr sakin pataob try nio ibend lahat ng side nia lumalaban
Pr lng s po s 2x3 n size pataob Ang matibay
now i know,,,,
Ang liit ng drawing mo
Padapa nalang madali pa, tapos isang load lng ang bubuhatin, solve na computer2x
mali! dapat pointing upward, dahil ang load ay vertical which is flowing to imaginary shear point, so, to resist the load flowing to shear point dapat pointing upward.
Mas mahina po ang section pag pointing downward..nakabase po ang lakas ng c purlin sa location ng shear center..Mas malakas po pag pointing up, buo ang shear flow unless kung pointing downward, half lang gagana ang shear flow ng section kaya mahina, ....thank you po and sorry po..
All opinions are welcome to this channel, Thanks for watching!
thank you po