OPTIMIZATION OF A RC SLAB(CONCEALED)BEAM

[D.Jaya]

Dear Structural Engineers

In a residential building of a footprint of 18m x 10 m , the Architect want to introduce a Slab beam (sometimes refers to as concealed beam/band beam) at the 1st floor and roof terrace slab at AB and CD(ref:Fig 1 ). Clear span to be 7.68 meters. I done some preliminary calculations and found that the slab to be at least 175mm thick at this section of the structure & other sections ,125 mm floor slab is sufficient.
I want to have an idea about the following:
1. For economy, can we arrange the slab beam reinforcement (as a conventional beam) as indicated in Figure 2?

2. If the shear force(v) at the location E on slab beam CD , and if vc< v <0.8(fcu)^0.5 (according to BS8110 ) -then is it enough to design shear reinforcement (links)or is there any other factors to be checked ?(like deflection)how to check deflection of a slab beam ?

3. The shear links to be provided at location E to be 2T12@75mm c/c and it seems the RF congested at this location. Any idea to solve this….
Your valuable comments are highly welcome please

 

[HTURKAK]

The title of the thread is (OPTIMIZATION OF A RC SLAB(CONCEALED)BEAM )..

Just by looking to the sketch provided, i would say;

- The concealed beam depth (175 mm) with span 7.68 m is not reasonable..

- Apparently the beam C-D will not satisfy deflection criteria..

- I would suggest , increase the beam dimensions to around ( 350h X 800 w) or change the slab system ( say one way slab with beam +infill blocks )

You may post the plan sketches to get better responds.






I cannot give you the formula for success, but I can give you the formula for failure..It is: Try to please everybody.

 

[D.Jaya]

Dear HTURKAK
In plan the other side dimensions(Y direction) are 3m for each side. This will give a proposed slab beam located at the longer side of a one way slab
Thanks for your comments.