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Is it possible to cast a beam under an already casted slab? Is there another method to correct an already casted slab with a large method to prevent it from deflecting?

Is it possible to cast a beam under an already casted slab? Is there another method to correct an already casted slab with a large method to prevent it from deflecting?

Is it possible to cast a beam under an already casted slab? Is there another method to correct an already casted slab with a large method to prevent it from deflecting?

johnson232:
u can use 9inch block. if the sketch u posted was followed. have u done the partition already?

Thank you sir. About to start.

johnson232:
my brother what is the problem?
the structural design look okay..

can I use 9" block to partition the slab?

The rough structural members

This is a rough diagram of the slab.

opalu:
1. I couldn't see the pictured properly so I do not really know what to say. Maybe if you send me pictures taken of the under of the slab and the columns I can say the corrections better.
2. Buildings do not always collapse due to such things except they are serious issues. However such negligence on the part of the artisans or the owner will definitely shorten the effective lifespan of the building and also result in cracks over time. But like I said it is when I get a clearer view of other structural elements that I can say categorically.
3. Secret beam is not efficient when the span is too long. I have explained before using a ruler as example. If you bend the ruler holding it when it is flat it bends easily. But Try to bend the ruler when held at the edge side and you find that it is not easy to bend.
What it means is that the secret/hidden beam and normal beam all require depth. The deeper the beam (effective depth), the stronger.
It is for this fact that secret beams are used when the span is short. Those who use secret/hidden/inner beams for long spans do not really have the grasp of the engineering behind it. With all due respects.

You want to demarcate the slab on top of the slab or under the slab? If it up, it will depend on the grade of concrete you used. The mix ratio. If it's standard 1:2:4, then you would have used 175mm or 200mm thick concrete to be on a safer side especially if you are using mallams to do the casting.
With a strong mix and proper casting, you can use 9 inches blocks to partition.

From my experience, i discovered that each case is different and the problems and solutions are different.

Thanks a lot. Is it possible to increase the strength of a slab after it has been casted?

opalu:
You and Hajji M have already given the right explanations. The Poker Vi.brat.or should be used in every concrete work. So many builders don't like to use it for columns and slabs and lintels. That is not good. Usually the intersection btw columns and beam and slabs have internal gaps that tapping or any other primitive method won't solve

Thank you very much.
1) Please how can one correct the errors in the images I sent?
2) Can it lead to the collapse of the building?
3) Can a slab with a very large area be partitioned with 9" blocks? The slab has Ly = 8.5 and Lx = 4.6. The slab was designed with Y12@ 200mm c/c both ways with a 150mm heigh. The contractor passed two internal beams(2Y16 T&B) at d middle of the Ly and Lx sides.
Will it hold if 9" blocks are used to partition rooms on it with a passage at one side?

Other pictures

opalu:
Correct explanations
Thanks.

Thank you for your quick response. God bless you. The reason I asked is that a decking was cast without vibrating machine. I came to the site after it was casted. I noticed the carpenter, iron bender, electrician nd caster did a very bad job.
The images I took are attached. I would like to know what can be done to correct this error. Also, I want to know if this can lead to the collapse of the building?

jejeman:
Pls does a room size of 3.35m by 4.23m needs a beam across it centre apart from the beam on the surrounding wall?

No you don't. Let the beams be designed properly and adequate reinforcement provided.

What are the dangers of not using a vibrating machine.
The decking has no much beams. Beams are not more than 3m with Y16 top and bottom. Is it safe to cast it without the vibrating machine? Will there be risk of collapse?