2 -How to Calculate Dead & Live Loads on a Steel Truss | STAAD.Pro Tutorial Part 2 - video Dailymotion

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In this video, learn how to calculate dead loads and live loads on a steel truss structure using STAAD.Pro. A clear and practical explanation ideal for civil engineering students and structural designers.  #STAADPro #LoadCalculation #SteelTruss #DeadLoad #LiveLoad #CivilEngineering

Transcript

00:00so now in the further lectures we shall like we already you know added the properties here so now

00:05we shall try to assign the properties here so what we can do is that as i had discussed that

00:11usually the outer periphery the outer periphery of the truss section that is usually the uh what

00:17we can see as a double angle sections so uh what we can do is that we can just press control key

00:24option on a keyboard and then click all the members here so that all the multiple members

00:30can be selected here so we can like select all of these members like this here and then this member

00:38also and this we can assign as a 75 by uh 75 by 8 and double angle uh just a minute this should be

00:4875 by 75 by 8 long like back to back double angle yeah now it is okay 75 by 75 by 8 long like back

00:57to back double angle uh the system has crashed so that is why you maybe have seen the difference

01:03between the standard and legacy so in both the options like the member sizes are almost same

01:08and that the properties are same so i have added this as a legacy but you can as a discussion

01:15the earlier lecture you can add that from the uh like uh standard option also that is standard database

01:22and after that we can uh these members are the one that carries the maximum tension or compression

01:28depending on the loading uh transfer so this we can assign it as 75 by 75 by 8 and further members like

01:34the vertical members they carry the minimum and most of them are like uh if we can say redundant members

01:39only uh they don't carry much of we can say the forces so this we can assign it as the minimum section

01:47that is 50 by 50 by 8 and the missing members here uh this we have assigned 75 by 75 by 8.

01:55the remaining members what we can do is that instead of 100 by 100 by 8 we can select 65 by 65 by 8 also

02:02so this we can change it to 65 by 65 by 8 and this we can like click the members here like this

02:16and this we can assign it to yes so we can like go to a missing property and missing property so here we

02:22can see that all the members have been assigned the properties so geometry is done that is closed

02:29property section is also done they are also assigned after that we can go to the materials material here

02:34it has been selected as the steel section and the value of the yield strength and tensile strength that

02:40we can enter it in the when we are entering the design parameters here after that the important

02:45parameter is the specification now the thing is that if you have selected here if you can open the

02:52start editor option here the command that we can see here is that it has been selected as a space

03:00now the first you know uh discussion that i want to do here is that we first of all let us just select

03:06the start trust option here so in the trust option we don't need to do any kind of specification in the

03:15next trial we shall run it as a space uh option and then we can assign the specification

03:21but as i said in the earlier lecture we shall be going with the ideal uh truss system second option

03:29is a like the fifth option is a support option so here we can click on the create here we can see

03:36different kinds of options that is foundation and inclined tension compression you don't need to

03:40like worry about if you have just started using the start it is very easy the fixture is the one which

03:46you have read in your college that the fixed support pinned support is the one that can only you know

03:52take the horizontal reaction and vertical reaction it cannot take any kind of bending moment fixed

03:58support is the one that can take the axial load vertical load and bending moment also fixed but is the

04:04one in which we can you know uh assign the type of the supporting system let us say our system

04:12cannot take any kind of bending moment and cannot take the horizontal forces also it can only take fy so

04:18in the terms of the we can say undergraduate studies which are in the terms of structural analysis language

04:24it shall be a roller support so we can left click on add here second option we can just go to pinned

04:31and then left click on add here so this support we can assign it as a pinned support this support we

04:39can assign it as a what we can see as a roller support now one is pinned and the second one is the we can

04:47say uh a fixed but option and in the term form of we can say in the language of the start but as uh we can

04:55say roller support in the language of the structural analysis so now the supporting conditions are also

05:00like done the last option is the load cases details now that is an important parameter now you know there are

05:09different approaches uh to assign the loading to the trust option and like some of them what they do is

05:21that they do calculate the individual loading as a node node load on each and every node that is like

05:28quite time consuming and that does not give much difference in the results so before that let us just

05:34you know do the basic steps we can select the loading type here as dead then here we can select it as a

05:41dead load after that we can go to the live here we can add as a live load

05:49then we can select here as a wind so here we can select it as a wlx and you know this kind of structure

05:59does not go on in the seismic loading they always go on in the we can say dead load live load

06:04combination of the gravity loads or we can say snow loads if this particular process in the himalayan

06:10region or most of the times it too governs in the case of the wind loading only so we can click on

06:17dead load here we can click on the self-adoption here we can enter minus 1.1 and then left click on add

06:24here so we can left click on assign to view and yes now uh if you want to assign the loading of the

06:32sheeting here so to assign the loading of the sheeting we can you know just uh go to the member load

06:39option here and here we can select the gy that is the load shall be assigned to the gravity or we can

06:44say the global y direction now if you want to calculate this particular value of the we can say

06:51uh uh the dead loading of the sheeting and the dead loading of the purlins how we can calculate that

06:58that we shall just check so now what we shall uh you know the problem under discussion is that we do

07:04need to calculate the dead load now the dead load shall be the weight of the purlins that shall be

07:10resting on this particular we can say trust member the second uh dead loading shall be the weight of

07:16the sheeting now this sheeting is like uh of various types uh if you are talking about the india

07:24in the good projects or in the projects where the quality is very important they use galvalium sheeting

07:31uh galvalium is basically made of two words galvanized and aluminium and the thickness of this

07:38particular sheeting it is usually 0.5 and the language that is used is either bmt or tct

07:46so bmt is a base metal thickness and tct is the total coated thickness let me just write it here

07:51so this sheeting usually looks something like this the one that you must have seen in the we can say

08:06metro buildings also and uh like in the uh common uh language of india it is also known as metro

08:13sheeting by some fabricators so next time you know you're on a job and someone says metro sheeting this

08:19is the sheet that they are referring to that is galvalium sheeting and the thing here is that uh the

08:25this particular sheeting thickness is usually 0.5 mm and 0.5 mm is usually the total thickness

08:34including the coating so if you're talking about the base metal thickness it is usually in the range of

08:390.42 or 0.4 and after coating it becomes 0.5 so 0.5 is usually the total coated thickness in majority of the

08:47cases and the sheeting weight is usually 5 kg per meter square second aspect that we do need to you

08:57know calculate is the weight of the purlins now again the weight of the purlins that depends on this

09:02particular center to center spacing so in our case we have taken as approximately 1.45 or we can take it

09:11as 1.5 meter also so usually you know the weight of the sheeting and purlins so sheeting as we have

09:18discussed is approximately in the range of 5 kg per meter square and the purlins weight that comes out

09:25to be approximately 15 kg per meter square that is the weight of the purlins when we are dividing it by

09:30the we can say contributory area uh let us say this is the purlins and contributory area is let us say we can

09:37say 0.75 meter on the left 0.75 meter on the right with that usually uh the purlins weight comes out to

09:44be 15 kg per meter square so the total weight comes out to be 20 kg per meter square which when multiplied

09:51with 6 meter that is center to center span that gives us approximately we can say 1.2 kilonewton per

09:58running meter so that udn we do need to apply on the top of the truss the live load as per the code that

10:07is approximately we can say 75 kg per meter square which when again multiplied with the contributory

10:13we can say the center to center spacing of the two trusses that gives us approximately we can say 4.5

10:20kilonewton per running meter see basically 1 kilonewton is we can say 1000 newton or we can say 100 kg

10:30i'm not taking 9.8 i'm just rounding these numbers off so uh if you know uh you're talking about 100

10:38uh sorry here we are talking about 16 to uh 20 that is 120 so 120 kg is approximately we can say 1.2 kilonewton

10:50as it is a udn so we are applying per meter similarly here also we are talking about 16 to 75 that is 450 kg

10:58so 450 kg is 4.5 kilonewton which one again you know we are taking as it has a udl so the number

11:03conservative 4.5 kn per running meter so we have to apply 1.2 kn per running meter and 4.5 kn per

11:10running meter for dead load and live load respectively so here we can apply minus 1.2 that has to be

11:16applied in in the direction of the gravity and live load also that also we can take you know for member

11:23load load and here also we can apply minus 4.5 kn per running meter this you must have noticed that

11:29i had applied self weight as minus 1.1 usually in the structural steel design we have to take the 10

11:34percent as the weight for the structural steel connections so we can you know select all of

11:41these members here on the top we can select all of these members here assigned to selected beams and

11:51yes so we have applied the weight of the sheeting and purlin in the form of udl on the top and 4.5

11:58also this also again we can apply here so we can press shift plus v option on a keyboard to check the

12:05like values of the udl that we have applied and for the values of the wind load wind load usually

12:10either it can be in the form of suction that is acting away from the structure or it can be in the

12:16form of pressure that is acting uh towards the structure structure means that uh this part the

12:23one that is below this particular truss let us say this is the warehouse the one that i am drawing an

12:29imaginary rectangle here so either it can be in the form of we can say uh we can say pressure or suction

12:37so this we shall you know calculate that in the next lecture

2 -How to Calculate Dead & Live Loads on a Steel Truss | STAAD.Pro Tutorial Part 2

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