Yes, of course I need to analyze the existing slab.
I was also thinking of doing composite deck and not doweling the rebar (basically only the angles are doweled into the edges and not the rebar from the new slab) but then I have to worry about fireproofing, correct?
How would we reduce up an existing opening in a 10" thick flat 2 way slab? I'm going form about 8x12 down to a 4x3.
My ideas are:
1. Epoxy anchor angles into 2 sides of the opening then drop in form deck with rebar and concrete, epoxy doweling the rebar into the edges of existing.
2. Dowel rebar...
@dhengr: it's not a lousy client by any means and normally they follow and appreciate my advice. This is just one of those times where a combination of various factors lead us to this issue and yes, time is of the essence.
@phamENG: I'm a solo-dolo shop and this is literally the only time so...
Let me give a little bit more info: this is an existing warehouse space with masonry walls and steel columns, beams/trusses supporting the roof. There's no fireproofing on the beams. Sections of the roof need to be replaced and the client wants to go with LVLs and (now) wood joists. The space...
Is there any kind of code stipulation that prevents supporting secondary non-combustible framing members on primary combustible member? For example supporting C-joist roof framing on an LVL middle girder that's further supported on steel columns?
Further, is there code stipulation that prevents...
Does anyone have a quick reference to where in the ACI it states that minimum thickness of a concrete slab should be 2.5 times the largest aggregate in the mix?
A 6'-6" deep 24'x12' pit needs to be excavated in an existing basement. The clearance from slab to 1st floor joists is 9.5' so only a small minim excavator can be brought in. Is wood sheeting/lagging the only way to go or is there anything else that can be installed by hand or a small machine?
Why was it over-excavated to begin with? Have you not been around your share of fly-by-night contractors who have no idea what they're doing?
In all seriousness, in this particular case, it probably will have to be underpinned. I appreciate the input and I do understand all the details.
However...
Thanks for the answers.
But what is the theory on just putting the soil back? Let's say, hypothetically, that the final excavation does not need to be lower than the footing. Is there a problem with putting the over-excavated soil back and compacting?
I was called to a row house with party-line common walls where a contractor has over-excavated the basement, undercutting the foundation walls/footings by about a foot. Naturally, he got a stop work order from the inspector. The bottom of new slab isn't going to be below the existing footing...
So the contractor built the form but is unable to pour for a while due to some unforseen conditions. Is there a code stipulation as to how long the form release agent can be on the forms before pouring the concrete?
Thanks JAE. I swear I've been looking at this damn table every now and then for years and was never able to come up with a satisfying answer. I'm glad I'm not the only one that thinks it doesn't really make sense.
I suppose I didn't phrase my question clearly. Let me try again. ACI 530.1 Table 2 has 3 columns. The first column lists various psi block (1,900 2,800 3,750 4,800) combined with type M or type S. The second column lists DIFFERENT various psi block (1,900 2,125 3,050 4,050 5,250) combined with...
ACI 530.1-05 Table 2
Why are there different strength units listed under Type M or S and Type N mortar?
What does this mean? That 2150 psi units can only be used with type N mortar?
