I'm going to analyze a building model in SAP software as nonlinear time history under wind load.Can anyone help me?
Tray to find any book about nonlinear time history analysis i.e. “THREE-DIMENSIONAL STATIC AND DYNAMIC ANALYSIS OF STRUCTURES” by Edward L. WILSON http://www.seabc.ca/documents/seminars/dynamic_analysis_basics.pdf
Dear Ali,
I hope this helps, actually I have never done it for wind loads before but I did nearly the same for ground motion records:
1- Wind loads change along the height of building, therefore I think if we want to change it with the time, we need to define different time-history functions at specific heights (e.g. story level) and assign these to stories. In this regard, in Define menu, Functions sub-menu, you will find Time-History which enables you to define a time-history (specific value which changes in time) with any desired function type.
2- In Define menu and Load patterns sub-menu, define a wind load pattern with wind type and selecting "none" case in auto lateral load pattern.
3-In Define menu and Load cases sub-menu, select the wind load case which you have defined in previous step and push the button of "Modify/Show Load Case". Then, change load case type to "Time-History", Analysis type to "Nonlinear". in loads applied case of the form, select "Load Pattern" in load type because the wind load is not acceleration, Load name as "Wind" which is previously defined, Function as the one you defined in step 1 and scale factor as 1 and push the OK. I forget to say that in defining function, it may be good to define Force versus time.
4- Now select the nodes at outer sides of the building where wind loads are force them. Then, go to Assign menu and Joint Loads sub-menu. Select the forces, in opened form Select Load pattern name as "Wind" which is previously defined and apply 1 to desired Global direction that you interest to apply wind load. it is because that we have previously defined the Time-history function as force.
5- Now run the model. Don't forget to assign nonlinear hinges or element to model. which you can find it anywhere.
6- If you need to plot time-history outputs (e.g. displacement of specific joint), first select the joint. then, go to Display menu and Show plot Functions sub-menu. Select the load case as "Wind". Define the interested time range that you want to plot the output. push the Define Plot Functions. Select the name of selected joint and push the Modify/Show Plot Function. Select the interested output, for example "Displ" in "UX" direction and OK it. Now you will see it on List of Functions, select it and push the add to assign it as Vertical Functions. Horizontal Plot Functions could be Time or any of the outputs that you have defined in List of Functions. Label the axis and push the display. then you will see how it works.
I checked it in SAP and it seems to work but please check the details.
Bests
Reza
- Badges
- Science topic
- Similar topics
- Mathematical Sciences
- Graphs