The attached picture is from ETABS video regarding sequential construction modeling: https://www.youtube.com/watch?v=oi2rdht_pZY
The left and right images are identical (same structural members and loads), except that the left image is considering the entire structural as a whole; while the...
This should be a quick question for the experienced CMU forks.
In ACI 530, par 3.3.4.1.1, to determine the axial strength, we need the h/r ratio. I tho the r should be the r-net, because usually net sectional properties are used for stress/strain computation, while average sectional properties...
@KootK
The floor system is diaphragm rated plywood sheathing supported by cold form steel c joists spaced @ 16" O.C. Plan dimension is 47ft x 20 ft, 14 ft of the 47 ft is the extension. No sure about the edge angle, I would assume no.
JAE,
Those are some good points.
1) I plan to overlap the diaphragm between the new and existing floor.
2) Chords shall be bond beam and designed for the shear and axial forces due to moment caused by lateral forces.
3) Item 1)
4) When you said "top of CMU wall", you meant on each floor level...
Doing a building extension design for a 4-story building (40ft/12.2m height).
Existing structural is a closed CMU building 33ft x 20ft (10m x 6m) dimension.
Extension is to be done by knocking down one side of the CMU wall and extend into the back yard for 14ft (4.3m). A steel moment frame is...
You are right. I thought the dead load in DL2 would have vertical seismic effect in Beam 1 and 2. Now I think about it, they would only affect the columns and Beam A and B, not 1 and 2. Although, in practice, the floor is probably one piece and Beam 1 and 2 would essentially receive some...
@wonnabeSE
for the 1.2D, the D is the dead load the member is supporting.
for the 0.2SDSD, the D is the dead load that's causing the seismic lateral load.
They DO NOT have to be the same D. If they are not the same D, (1.2 + 0.2SDS)D + ρE + L + 0.2S does not apply.
For a simple example...
The question was: are the D's that appear in the load combination (1.2D and the 0.2SDSD) the same D, or can they be different.
In ASCE 7-10 12.4.2.3, they seem to say that the D should be the same D:
"...the following seismic load combination...shall be used in lieu of the seismic load...
So in another word, we could end up with a situation where:
1.2D1+1.0(pQE + 0.2SDSD2)+L+0.2S
where D1 is the moment frame's self weight dead load; and D2 include the frame's self weight plus the part of the building's dead load that the frame is taking lateral load from.
Interesting.
Load Combination 5 and 7:
1.2D+1.0E+L+0.2S
0.9D+1.0E
where D is defined as simply "dead load" and E = earthquake load, calculated as following:
E = Eh +- Ev = pQE +- 0.2SDSD
where QE is the effect of horizontal seismic effect, and 0.2SDSD is the vertical seismic effect.
Now, suppose designing a...
Hello.
Many masonry buildings in big cities, such as New York, are narrow rectangular shape. The interior floor joists/beams typically runs along the short direction, supported by the wall. So, the long direction wall is a bearing wall + shear wall, while the short direction wall is none load...
Designing the connection between the column and the base plate. The column is modeled as pin connected at the base. The column is designed for primarily gravity load, but need to resist some shear due to lateral loads.
There are a lot of design guides out there about how to design the base...
Designing a T beam subject to flexural load and very small axial compression load.
I calculated the axial capacity of the beam as a whole T beam according to AISC Spec and it's much larger than the load (28kips > 1kip factored load).
But then I'm worried because the beam is connected thru web...
