Solid Slab 10m span 1

[Ahmed A. Alamin]

Hellow engineers, i'm designing a leture halls building. The spans in one direction are 10m and 6m respectively and in the other direction are 5m. As my first option" attempt" i tried solid slab with a thickness of 20cm and beams are 70cm deep by 35cm width. Honestly, i didn't expect this choice would succeed but to my suprise elements did good, even the long term deflection was within the allowable limits. This made me question my design.Any sugessrion? Do experienced engineers find slab and beam cross-section reasonable?..i'm using CSi Etabs and Safe
"Live load = 4KN/m2, finishes 1.5 KN/m2, and partions are 18 KN/m..

 

[JAE]

Are these multiple continuous spans or one single simple span?

From ACI 318 here are the minimum thicknesses required assuming you don't check deflections:

Simple Spans
L/20 - for a 10m span this results in a thickness of 50cm
L/20 - for a 6m span this results in a thickness of 30cm

One end continuous
L/24 - for a 10m span this results in a thickness of 42cm
L/20 - for a 6m span this results in a thickness of 25cm

Both ends continuous
L/28 - for a 10m span this results in a thickness of 36cm
L/20 - for a 6m span this results in a thickness of 22cm

 

[Agent666]

I'm surprised the deflections work, are you sure you've allowed for the effective stiffness due to cracking and tension stiffening effects.

 

[Guest262653]

We need a sketch with the spans and the position of beams.

From what you wrote, I assume you have 2 way solid slabs fully supported on beams on all directions, with short spans of 5m and long spans of 10m. If that's the case, the short span governs and 20cm thick seems ok.

 

[ooox]

Where are the partition loads applied? 18kN/m is significant, I hope its supported on the beams.

A sketch showing the framing arrangement and application of loads would be helpful

 

[Ahmed A. Alamin]

Yes partion loads are supported on Beams.

 

[Settingsun]

Prestressed?

 

[r13]

Is this a slab panel surrounded by beams, or this is a T beam design? You need to provide a floor plan for people to correctly understand your problems and concerns.