Concrete walls - Load distribution to foundations
Concrete walls - Load distribution to foundations
(OP)
We are designing a 12 story building in etabs using a system of shear walls and one and two way concrete slabs. In most cases the walls are 50ft long until we get to the parking garage where a 30ft hole is punched through. The walls on each side of the opening are 10ft long and 12 inches thick. Ignoring lateral effects we expected the loads in the wall to be evenly distributed to the foundations below these lower walls. However etabs is transferring all the load to the outside edge of the support walls and not distributing it evenly as we would have assumed. why is this.





RE: Concrete walls - Load distribution to foundations
RE: Concrete walls - Load distribution to foundations
RE: Concrete walls - Load distribution to foundations
RE: Concrete walls - Load distribution to foundations
RE: Concrete walls - Load distribution to foundations
RE: Concrete walls - Load distribution to foundations
RE: Concrete walls - Load distribution to foundations
RE: Concrete walls - Load distribution to foundations
RE: Concrete walls - Load distribution to foundations
From CSI on SAFE:
• How do I input piles for my basemat?
You will need to input springs at pile locations using stiffness values equivalent to that of the pile. In order to draw a spring, you will first need to use 'Draw Point Object' and click at pile locations. You can draw the points by snapping to grids, or by drawing the points, then right clicking each of them to modify XY coordinates. After drawing your 'pile' points, select them by clicking them or windowing around them, then Assign > Column Supports > Add New Property, and checkbox Spring Constants Option to input spring values for the piles.
RE: Concrete walls - Load distribution to foundations
RE: Concrete walls - Load distribution to foundations
If you encountered the same problems before at least you can use it as your reference.
By the way CSI said use stiffness values equivalent to the pile.
RE: Concrete walls - Load distribution to foundations
RE: Concrete walls - Load distribution to foundations
RE: Concrete walls - Load distribution to foundations
You can at least try to get your reactions directly from the grade beams...well just use it as your pile cap and get the reactions from the wall itself.
I'm not really comfortable with the short column approach.
Best of luck to you guys...
RE: Concrete walls - Load distribution to foundations
Thanks for your help. We removed the piles and put in supports. One issue we found was the walls had been drawn across the supports and not from support to support. This made the wall span to the end supports and applied very littleload to the interior supports.
Drawing them as piers to each support applies more load to the internal supports, however, is this a correct way of modelling a concrete wall. If the wall is monolithic it would have to crack and deflect significantly before any load is applied to the center supports.
Any thoughts on this.
RE: Concrete walls - Load distribution to foundations
http://www.csiberkeley.com/Support_WL_ETABS.html
RE: Concrete walls - Load distribution to foundations
I have the feeling that the walls are not meshed. Is this the case?