STRUCTURAL ENGINEERING FORUM OF INDIA [SEFI]

ramu_se · SEFI Regulars Joined: 30 Oct 2017 Posts: 36

Dear All,

How to design the two way slab when the wall load in coming on the slab?

I have attached the image of the slab.

Please guide me how to design this kind of slab.

Regards,
Ramu.

renju mathew · SEFI Member Joined: 18 Feb 2016 Posts: 15

Dear ramu,

This slab spans much bigger. So, if the slab is discontinuous on all four edges, then the thickness of slab will be 150mm and rebars - 12 mm dia Bars at 175 mm C/C on towards both directions. This design is uneconomical in my point of view. so you might consider splitting this slab into two by providing a beam under that wall which comes over the slab.

You can provide concealed beams under the walls if the distance between the wall and the support is less than 2 m. in this case, i think its not possible.

es_jayakumar · Posted: Sun Sep 27, 2020 5:45 am Post subject:

As pointed out by Er.Renju Mathew, you have to provide sufficient depth to the slab, considering its large span (4.8m). As advised by him, try to introduce a beam below the proposed wall. If there is no door opening in the wall, you can choose to make the beam up-standing also, should you want to avoid the unsightliness of the beam projection beneath. If you cannot try light weight partitions (wooden, aluminium, AAC block etc.) for the wall, use half-brick wall. If the supporting beam has to be done away with, you have to analyse the two-way slab using "Pigeaud"s Curves". A worthy worked out example for a similar case can be found in the book "Design of Reinforced concrete Structures" by Ashok Kumar Gupta (Galgotia Publications). I think, this book is out of print now. You can analyse the slab using STAAD also, by modeling the it using plate elements. Don't forget to check the deflection of the slab.

E S Jayakumar

ramu_se · SEFI Regulars Joined: 30 Oct 2017 Posts: 36

Thank you Renju sir and Jayakumar sir.

ramu_se · SEFI Regulars Joined: 30 Oct 2017 Posts: 36

Dear Jayakumar sir,

I have done staad model for the slab and got maximum deflection as 5.4mm.I have converted the wall load as nodal load and applied on the plate nodes.
Attached the loading details for your reference. Please correct me if anything wrong.

Regards,
Ramu.

es_jayakumar · Posted: Sun Sep 27, 2020 2:12 pm Post subject:

Please post the STAAD file.

ramu_se · SEFI Regulars Joined: 30 Oct 2017 Posts: 36

Sir,Please find the staad file.

badamsundararao · Posted: Sun Sep 27, 2020 5:15 pm Post subject: BRICK WALL ON SLAB

Design a beam to a width of 100mm+2x depth of slab,sothat,the wall load will be disbursed@45degrees ,with depth of beam from minimum depth as per deflection consideration,so that the beam depth may not affect much from Ambiance point of view. Use AAC blocks to reduce the Dead load.

es_jayakumar · Posted: Mon Sep 28, 2020 2:12 am Post subject:

ramu_se · SEFI Regulars Joined: 30 Oct 2017 Posts: 36

I have analysed the beam in staad.

Beam size 400 width(100+2xdepth of slab)and 150mm depth since i have considered 150mm slab thickness

wall load - 3.15 kN/m
wall thickness- 150mm,AACblocks

We have to design this beam and provide reinforcement for 400mm wide beam inside the slab?

Please find the attached file.

Regards,
Ramu.