abdulwastecx:



Check out the following books
1. Reinforced concrete: design theory and examples ( first and second edition) by T. J. MACGINLEY and B. S. CHOO

2. Reinforced concrete design to BS8110 - simply explained (A H ALEN)

3. Reinforced concrete designer's handbook (C E reynolds and J C Steadman.

4. Reinforced concrete design ( Bill Mosley, John Bungey and Ray Hulse).

These books were very helpful to me during my undergraduate years on reinforced concrete design.

I will also advice you to get all the BS 8110 for reinforced concrete design, steel table and structural detailing to Bs 8110. You need to also get BS 6399 loadings for building. These codes will make it easy for you to do your design.

Structural design requires lit of simple mathematics unlike structural analysis that requires advanced and vigorous maths. What you need to do is devote more time to it, understand all the steps involved and prepare your mind towards it.

During my undergraduate years, grade (gp) was secondary to me, understanding the design was more important to me. I study these things to be able to do the design, so I use lit of practical examples like working real architectural drawings instead of those simple panels giving in the classrooms.

Very helpful, I thought I am the only one finding the RC design of Oyenuga a bit confusing. I will try to download these if I am able to or just visit a good campus bookshop.

abdulwastecx:


There are beams but these beams are of the same depth as the rib ( the small beam of the waffle). These beams are wider than normal beams in solid slab construction ( width greater than 225mm in most cases).

Thanks for this explanation. Nigerian universities are making these things very difficult for us. Thanks to you guys online helping us with some key points... you can never guess how far they have helped us. You see, it's hard knowing the kind of beams in an architectural drawing. For instance, how do I know a continous beam should be at a slab run? I asked this because, all beams I can get on a plan looks more like simply supported beams. That is, I always want to end a beam between two supports... when do I decide to make the supports several..... thanks

abdulwastecx:


This is a waffle slab with permanent shuttering (former). Waffle slab is a slab with rib beam in two direction (different from ribbed slab with rib only in one direction.
The ribbed are space at a regular distance between each other based on formers, life load and code specifications.

Waffles slab is made up of
1. Topping
2. Series of rib beam accros both the short and long span of the slab.
3. Former ( the bubble above, hollow block, clay block, plastic pod, polystyrene pod etc) which remain part of the construction after the Formwork is removed.

In most cases the waffle slab is designed in such a way that the topping is not consider to contribute to structural strength but only to linked the rib beams together. The topping can also be made of concrete of not necessarily of the same strength as that used in ribs.

The former (polystyrene pod, bubble or clay block) are not consider to contribute to the slab strength in the design calculation most time.

The major advantage of these floor is the reduction in weight achieved by removing part of the concrete section below the neutral axis and replacing that with lighter weight materials. These types of construction are economical for building where there are long spans, over between 5m to 6m with light to moderate life load (1.5 - 3kN/m2), such as residential houses, schools, hospital, hotels etc. They would not be suitable for floors having heavy load like warehouse, production facilities, garage etc

seriously u nor dey give starters hope at all at all.... when do I know all these? lol

talk2riel:

How is this risky?


Civil Engineering is all about strength, durability, serviceability and optimal cost effectiveness in the construction of element.




This construction made use of fire baked bricks site, located in kaduna. Classical clay pot are sometimes use. Wonder why people are so surprised seeing this method of construction.

Please forgive my ignorance. Am just a young engineer.
From this image, so there will be no reinforcements between the block work or are dey just left hanging.

Some other advantages I can add are as follows:

1. The waffle floor construction allows you to have larger beam spans, and hence eliminate or reduce the use of columns (or pillar in lay man's language) especially where open, unobstructed area is desirable e.g churches, halls, etc.

2. In a multi-storey building, the cummulative savings in weight of each floor will reduce the cost of foundation significantly, as the foundation is meant to carry the total weight of the building.

Also, for those wondering if the construction is safe or not, it is a very safe and proven construction method, as long as a qualified structural engineer did the design, and the construction contractor follows the drawings and use the right materials. I first saw the waffle slab it years ago as in one of the auditoriums at the Law School in Victoria Island, Lagos about 18 years ago, and the building has been in existence for decades.

Hope this helps.

Kunlef.

najoe07:
As someone has rightly pointed, it reduces the volume of concrete, it sound proofs, temperature regulation due to the void in the concrete. It is worth to know that this type of slabs are very expensive and they use more reinforcement compared to flat slab. Hollow bricks can be used as well and the result is fantastic! Here is one I supervised. (Waffle slab or I call it insulated ribbed slab)

not advisable to use bricks, because the bricks still adds weight. Unlike the plastic balls that add little or no weight

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