Thanks a lot for this great video However i wonder why you model the cable geometry as undeformed length rather than tensioning it from either one of it's ends (Target force). second thing, why haven't you use a nonlinear analysis. Is this because you considered that the cables are straight and no sag would occur.
Actually you are very right! i shouldn't have! but I'm 100% a hardcore steel guy so u can see how i dont like cables that much :). I kid the cables! Ok - undeformed shape - in this case it represents a very preliminary investigation of what i wanted to show in this video. HOWEVER, it is very easy once this is done and you reach a point where a design for the cable/s.strand diameter(s) can be considered close enough to "tune" the cables using a unit load method - i can provide more info, perhaps a tutorial on this if u are interested further (target forcing) :)! Nonlinearity - Actually the original video was assuming second/third order effects on the structure, however, i am only allowed a particular amount of time of video to upload, also, i wanted to (at the moment) to keep this as simple as possible (maybe geometry based if you want), this is something that i do have a ready video for so i could always upload upon request :) please do let me know. thanks for viewing :)
Hello, here is a subscriber to the channel. I am carrying out a final project of a cable-stayed bridge. I have a doubt, since I would like to remove the axles from the braces without having to first do continuous beam analysis and project to see how much each cable takes. So if I decide to check it with the cables, I assign a very small area for it to catch all the corresponding reaction but it is not like that, the value is extremely low .... There is some way to see the axis of the tie rod without defining an area like what can be done with the frame element?
We are onto model a Service Rig Mast and it needs to be stated to a stable ground with a cable. So I'm working on a cable, which type of material i should create for cable behaviour? It's steel yes, and steel is isotropic, but when it comes to thinking; cable doesnt behave the same from all directions at all. So i'm stuck, any help or advice could be life saving. Thanks!!
You rock! Really good video, hopefully one day i will manage the sap 2000 as you. By the way how could i do for avoid the axial forces in a cable, due that i have in my project a cable that never will work with axial?
+Carlos Ollero a cable cannot contain axial compression as you said and you are absolutely right! it can contain axial tension - you need to set up the element as a cable! if i remember correctly - either right click on the element either select element and go to the define menu and its in there to set it as a CABLE member only! this will remove all other effects! a cautionary note: you need to be careful with sap2000! it will NOT assess instability for you! it will perform the analysis in its sequence - set your analysis as 3rd order analysis! OR post critical! THIS IS SOS when analysis cables!
+miket tsappas My project is on progressive collapse of cable stayed bridge.How should i consider material and geometrical non linearity ? and should i model cables as cables or model cables as frames?
Always model cables as cables except for some very special circumstances! In the event where you require material.nonlinearity for such models (I.e bridges) I would suggest that you use rstab or lusas - u can find some help from these top quality pros here - www.engineworx.org lol :p
sorry for the late reply. you should model cables as cables, however you need to make sure that you activate member divisions for catenation to take place! now for progressive collapse - this is usually visible on the checks of the model! when you run a structure on which you have failure you can see where the failure is going to start however when some members change you need to keep in mind that the whole load is redistributed! the whole progressive collapse situation is going to be more clear to you once you study postcritical analysis! the best way forward for you here is to use postcritical analysis which is something that sap2000 will give you a VERY hard time figuring out! there are other software out there that are far more capable in performing this for you and that are generally better and easier to use than SAP2000! CSI has really let themselves go out of competition
did you divide the cables? in my experience this is happening because either the software doesn't recognise that the member you are simulating is cable or if cables are not divided/activated (catenary effects is SOS when simulating cables this is activated only when the cables are divided) sometimes to activate cable members adding tension after catenarion is required
Mike Tsappas sir I need ur help because I have project on cable bridge but when I am designing the cable it's moves out of the deck can u give ur mail id so that I share model to you and u help me
Thanks a lot for this great video
However i wonder why you model the cable geometry as undeformed length rather than tensioning it from either one of it's ends (Target force).
second thing, why haven't you use a nonlinear analysis. Is this because you considered that the cables are straight and no sag would occur.
Actually you are very right! i shouldn't have! but I'm 100% a hardcore steel guy so u can see how i dont like cables that much :). I kid the cables!
Ok -
undeformed shape - in this case it represents a very preliminary investigation of what i wanted to show in this video. HOWEVER, it is very easy once this is done and you reach a point where a design for the cable/s.strand diameter(s) can be considered close enough to "tune" the cables using a unit load method - i can provide more info, perhaps a tutorial on this if u are interested further (target forcing) :)!
Nonlinearity - Actually the original video was assuming second/third order effects on the structure, however, i am only allowed a particular amount of time of video to upload, also, i wanted to (at the moment) to keep this as simple as possible (maybe geometry based if you want), this is something that i do have a ready video for so i could always upload upon request :)
please do let me know. thanks for viewing :)
Very interesting and useful, thank you very much!
Hello, here is a subscriber to the channel.
I am carrying out a final project of a cable-stayed bridge. I have a doubt,
since I would like to remove the axles from the braces without having to first
do continuous beam analysis and project to see how much each cable takes. So if
I decide to check it with the cables, I assign a very small area for it to
catch all the corresponding reaction but it is not like that, the value is
extremely low .... There is some way to see the axis of the tie rod without
defining an area like what can be done with the frame element?
We are onto model a Service Rig Mast and it needs to be stated to a stable ground with a cable. So I'm working on a cable, which type of material i should create for cable behaviour? It's steel yes, and steel is isotropic, but when it comes to thinking; cable doesnt behave the same from all directions at all. So i'm stuck, any help or advice could be life saving. Thanks!!
email me tsappasis @ gmail.com
Email me - tsappasis@gmail.com
Model this an isotropic material!
You rock!
Really good video, hopefully one day i will manage the sap 2000 as you.
By the way how could i do for avoid the axial forces in a cable, due that i have in my project a cable that never will work with axial?
+Carlos Ollero a cable cannot contain axial compression as you said and you are absolutely right! it can contain axial tension - you need to set up the element as a cable! if i remember correctly - either right click on the element either select element and go to the define menu and its in there to set it as a CABLE member only! this will remove all other effects! a cautionary note: you need to be careful with sap2000! it will NOT assess instability for you! it will perform the analysis in its sequence - set your analysis as 3rd order analysis! OR post critical! THIS IS SOS when analysis cables!
+miket tsappas My project is on progressive collapse of cable stayed bridge.How should i consider material and geometrical non linearity ? and should i model cables as cables or model cables as frames?
Always model cables as cables except for some very special circumstances! In the event where you require material.nonlinearity for such models (I.e bridges) I would suggest that you use rstab or lusas - u can find some help from these top quality pros here - www.engineworx.org lol :p
sorry for the late reply. you should model cables as cables, however you need to make sure that you activate member divisions for catenation to take place! now for progressive collapse - this is usually visible on the checks of the model! when you run a structure on which you have failure you can see where the failure is going to start however when some members change you need to keep in mind that the whole load is redistributed! the whole progressive collapse situation is going to be more clear to you once you study postcritical analysis! the best way forward for you here is to use postcritical analysis which is something that sap2000 will give you a VERY hard time figuring out! there are other software out there that are far more capable in performing this for you and that are generally better and easier to use than SAP2000! CSI has really let themselves go out of competition
how to calculate cable forces can you tell me sir ?
Man I'm doing the same thing as you but my cables go off the screen in the deformed view. Can you help me pleaseee
did you divide the cables? in my experience this is happening because either the software doesn't recognise that the member you are simulating is cable or if cables are not divided/activated (catenary effects is SOS when simulating cables this is activated only when the cables are divided) sometimes to activate cable members adding tension after catenarion is required
Mike Tsappas sir I need ur help because I have project on cable bridge but when I am designing the cable it's moves out of the deck can u give ur mail id so that I share model to you and u help me