Hmm so you essentially run the piers to the top of the wall? I thought the cast in place drilled shafts with the long bars fully developed into the beam and the column tie at the beam bottom bars provided a fixed support?
This is light frame 2-story residential construction and my backfill...
Yup the grade beam is supported by cast in place reinforced concrete drilled shafts at fixed intervals.
It's definitely supposed to be modeled as fixed - pinned. And the geotech has specified that retaining walls shall be supported on grade beam and cast-in-place drilled shafts. The wall should...
I'm designing a grade beam under a basement retaining wall which I'm modeling as fixed (grade beam / bottom) and pinned (top / floor joist). I checked the foundation retaining wall and it can span between supports with no shear reinforcement required, carrying the full bending moment, and has a...
There isn't really a functional limit. Eventually you would start having to use more steel is all. But I think there was a limit for the redundancy factor maybe. Which again just hits the functional limit by adding a 1.3 multiplier to the base shear.
Will do. It was a specific kind of note like.. flexible unblocked wood diaphragms in Seismic Design Category D shall not exceed 50 feet in any dimension. Something like that. It may have been somewhere else that essentially specified this limitation for typical design. Like the redundancy...
Yeah there are the aspect ratio limits for the various diaphragm types, it wasn't that. It might have been in the CBC in the structural section for Wood or something similar. There was some kind of upper limit on wood frame diaphragm dimensions. It may have been for the distance between...
I swear I saw this in the code somewhere that the there was a limit to the maximum distance between shearlines or a maximum diaphragm dimension, maybe specifically unblocked diaphragms. This is for SDC D structures in California. I think it was 50 feet. I should have book marked that or noted...
Yup mostly residential work. I do special inspections for epoxy rebar post-installed in hardened concrete frequently. They usually want the engineer of record to do the special inspections. Inspecting the rebar work would be fine. I haven't done concrete cylinders and slump tests since college...
That's what I thought too. Yes the deep foundation neglects the upper soils layer and relies on cast in place / buried grade beams spanning between cast in place drilled shafts that transmit the forces to the bedrock layer.
It's that 2.2 exception that has me questioning this. I've done a ton...
From the special inspection form in my jurisdiction, California Building Code (CBC)
Table 1705.8 – Cast-In-Place Deep Foundation Elements
For concrete elements, perform tests and additional special inspections in accordance
with Section 1705.3. (requires verifying mix design, rebar placement...
This is in response to the thread "Retrofit Holdown - Can't Use Epoxy" thread507-473250. You are correct that epoxy hold downs generally do not work in a typical 8" stem wall due to the concrete breakout strength and inability to have a ductile fuse. I discussed the HDU and similar hold downs...
