Here is the geotech's response for any interested:
"I’m just thinking out loud. I assume you are not interested in doing pile testing on the existing pile and incorporating it into the new design. I also assume that you don’t want to tie the existing pile into the new pile cap and just ignore...
I've got a new structure at a heavy industrial site sitting on a pile supported mat foundation. We discovered that there is an existing foundation within our footprint that was used for the removal of a large piece of equipment. We assume this is a pile cap with piles but can't find any...
In my admittedly limited connections to engineers at other companies, I'm actually noticing an opposite trend...that is, people either going back to RISA after trying another software for some period, or trying RISA for the first time.
Thanks Koot, I appreciate the detailed response and encouragement. I think I've satisfied any doubts I had about my design approach/assumptions. I've already designed my shear transfer reinforcement into the shear walls, so minimum required decking attachment to satisfy the items you listed...
What's the mechanism that explains this? Are we saying that once the concrete cures, the slab is so rigid that any connection of the decking to steel is negligible? In other words, decking connections are mostly for construction in this scenario? This was my design initial design assumption, but...
I'm designing a building with a rigid diaphragm (reinforced concrete slab with non-composite deck) and masonry shear walls. My design approach has been to have steel floor beams supporting the slab that carry gravity loads out to pilasters in the masonry walls. My slab is tied directly into the...
This is the approach I was going to default to next. I have the wall reactions from my model and use those in my shear diagram for the diaphragm. As long as loads from used in the model match what I use in the shear diagram, all should work out.
Let me switch the question up a bit.
I've got a model of the building in question which assumes rigid diaphragm. I keep trying to get the shear in my lower level walls to match the reactions I get by doing a shear diagram for the diaphragm. But now that I think about it, reactions at the shear...
If you're designing with a fully rigid diaphragm assumption, then the diaphragm does indeed have an ungodly stiffness...thus some of my confusion. For what it's worth, it feel like diaphragm design in general is one of the most ignored aspects of structural design, doesn't get nearly as much...
But even if you have a continuous shear wall, the diaphragm would be tied in to the wall in some way (shelf angle or similar). So wouldn't load from the shear wall above still make it into the diaphragm?
What about the situation where we also have a shear wall directly above a lower wall, but supported by the diaphragm? Are we considering this in the design of the diaphragm, or is it more of a direct transfer to the wall below?
How is everyone handling transfer forces from discontinuous shear walls above a diaphragm, similar to the situation shown below? I'm specifically looking for how to incorporate the shear wall loads into the shear diagram for the diaphragm. Are you adding them as point loads, or distributing...
A few more details:
-There was previous inspection done by a firm hired by the insurance company not long after the storm. The report identifies foundation cracks, several of which they call "new" or "fresh" There are some pictures that appear to show cracks with "bright" concrete that are...
Also, I'm not saying that the tree impact definitely caused 4.5 inches of settlement. I'm simply pointing out that the impacts from 2 large oak trees certainly did not help, and it is plausible that the foundation could have continued to perform adequately if not for the storm. Without having...
It is virtually impossible to prove that the damage was or was not there before the tree impact. Foundations are particularly hard to pinpoint the origin of damage. The damage to the rest of the house is intuitive...a tree fell on the roof, now the trusses are broken. But for whatever reason...
Good feedback so far. I think it's a good idea, as some have suggested, to do the calculation in reverse and see if the force required is feasible for a falling tree.
Let's say there was some pre-existing damage/cracking in the slab prior to the tree falling...it still seems disingenuous for...
Most of the tree is still laying on the ground, so I can fairly accurately calculate the weight. But you are right, it is a physics problem, which is why I'm struggling with it...not the type of thing we usually deal with.
