I have a two story building as the provided sketch. The ground floor will be completely open car park (no wind pressure) with only a stair case.
I can have vertical bracing along the 17 meters direction. In the short direction I am limited to using moment frames.
The problem is that I have a...
Concrete column buckling load (Pc) decreases significantly as the rigidity (EI) increases. The rigidity (EI) increases as the section stiffness (Ig) increases and as the reinforcement moment of inertia about the centroidal cross section (Ise) increases.
My question is, how to calculate the...
In reinforced concrete continuous beams with unequal spans similar to the attached sketch. Under gravity loading Column (A) has an uplift reaction. How would you detail the beam to column joint to transfer this uplift force ?
Also since this uplift force causes an increase in the reaction at...
In situations similar to the attached sketch, where one of the stories is higher than the other stories. Looking at the elevator columns. As a concept, I am wondering whether adding concrete beams connecting all of the columns in the middle of the floor height, would be sufficient in reducing...
I am interested in billboard signs design and I got my hands on the structural plans of one. The Billboard sign dimensions are 12 meters x 4 meters with a total height of 40 meter form the top of the footing to the billboard sign center. I added a sketch for reference. The footing dimension are...
In Multi-story precast concrete buildings, where the columns are cast on site, while the beams and the slabs are precast. The beams simply rest on the corbels, so the columns are not restrained by the beams or the slab, therefore what K factor should be used ?
Also. What height should we...
My contractor friend shared with me 4 borehole reports for a two storied building with an area 40x50 meters. I attached the soil report. I am not involved in this project but curious as how to deal with this situation
The columns spacing is approximately 10 meters so each column load is in the...
While working on CSI safe, I often find the software showing additional bottom reinforcement required near the columns. I cant really understand why is that especially that there will beams at those location with sufficient bottom reinforcement. For reference, I attached the plan I am working on...
I have a column supporting a transfer girder as shown in the attached sketch. The column has a transfer girder framing into it's weak axis, however the strong axis is not framing into a slab or a beam and hangs freely, I intend to use K =2 for the column around the strong axis. Still with K=2.0...
From my understanding, Voided slabs are essentially waffle slabs with a thin slab at the bottom. However, from most of the designs I have reviewed of voided slabs, I rarely see stirrups provided even at significantly high depth. Even with the voided slab rib depth being between ( 40 - 70 ) cm no...
Voided slabs are heavily marketed, and I really can't understand the hype, since most buildings are more so rectangular, biaxial bending is not really required. A famous voided slabs systems' Facebook page claims they used a 40 cm thick voided flat slab to support a 31 meter by 13 meters spaced...
In the attached file, over the highlighted joints, the beams show weird-looking moment diagrams. Is the software assuming continuity between the beam and the slab sections? I have found the same with trying different models that have similar joints. I don't find this reasonable, and is there a...
I was reading reinforced concrete mechanics by MacGregor about shear walls. The book says that a possible solution to decrease foundation size is to " Attach the base of the wall to the ground-floor diaphragm and basement floor to provide a horizontal force couple to react to the moment at the...
I am learning waffle slab design, and I am trying to find ways to simplify the modelling of depressions in waffle slabs. A conservative approach I came up with is to model depression as an opening. Then manually distribute the depressed slab's own weight and the design loads to the edges of the...
When modelling a simple story in CSI safe subject to uniform gravity loads only (Z-direction), I get columns reaction in the (X&Y directions). Why is that?
Sidenote, To determine the column moments, I usually assume the columns restraint is fixed at the top and the bottom similar to the...
If soldier piles and lagging are used during the excavation of the basement. Would you design the basement walls as a pinned cantilever? Or do you assume the soldier piles will be sufficient to resist the soil pressures on the long term?
Quoting the practical yield line design book published by the concrete center, " flat slabs on a rectangular grid of columns are essentially one-way continuous slabs in two directions and as such are analyzed and designed separately in both directions. "
I found their example a bit confusing...
I have an irregular mat footing similar to the attached sketch with light and heavily loaded columns. The lightly loaded columns are around the elevator opening.
For sketch,
https://files.engineering.com/getfile.aspx?folder=77acef45-7fc6-4b57-b781-2b5178e997ea&file=Review.pdf
I modeled it...
I am designing a steel beam bearing connection on 20X50 cm columns, the beam reaction is 140 kn. similar to the attached sketch.
https://files.engineering.com/getfile.aspx?folder=4e612d98-b134-42d0-a447-181b20510f45&file=sketch.pdf
Following the AISC manual section J8, the 50 cm length of...
I am doing a new steel residential 3-story building, but the client wants the columns to be concrete
( This is because of his unshakeable belief that concrete columns are safer )
Are there any references or tips to design the connection between the concrete columns and steel beams?
The...
