RAFT BASE

F

fatmaacil

New Member
Mrb my question is not related to ide, what should be taken into consideration while choosing the raft foundation thickness, apart from the ground values, earthquake zone, building height, can you help? It is generally preferred on floors with qem = 1.5 below. I guess it would be better if I asked what are the factors that determine the raft foundation height?
 
Factors such as soil type, earthquake zone, superstructure rigidity, the most unfavorable column effects, concrete quality, reinforcement quality, and the largest span are effective on the height of the raft flooring.
 
Let me tell you another pre-criteria. If you are laying slabs, consider 10 cm for each slab, and if you are using hollow floor slabs, consider each slab as 7 cm and multiply by the number of floors on the foundation, this will give you approximately how much height you will enter.
 
In the Raft Foundation System, the most basic control that binds the Height is stapling, including 1) increased loads on the columns 2) Concrete quality affects fctd, which in turn affects stapling 3) Staple perimeter; The larger the column, the higher the load it is exposed to, but the stapling circle will grow accordingly. 4) Ground Safety stress. An effect and reaction will occur opposite to a certain amount of vertical load on the ground. This also changes according to the ground safety stress. The expression of the coefficient x 10cm, which is known by everyone, is unrealistic. Because, in 2 buildings on the same square meter, the vertical load carried by the frequently (3 -3.5 m) columns is very different from the vertical load carried by the columns placed at 6-7 m intervals and transferred to the foundation. In other words, 50cm foundation height would be enough for a 6-storey building. In a 3-storey building, 50cm foundation height may not be enough. Stapling control is performed for the foundation in Idestatic, but there is no such control for the continuous foundation, but at least there are TS500 controls such that the continuous foundation height will not be less than one-tenth of the clean span.
 
Dear siromar, I have only mentioned a value for the front dimension here, otherwise it is not a definite criterion. Of course, the load on the soil and the column is an important criterion. Thank you..
 
Does the number and frequency of columns thrown in the system affect the (+) direction or (-) direction, or does the column's own weight and base size increase? I could not fully understand. Sometimes very strong systems are chosen, the columns are thrown extra, so the amount of load transferred by a column to the foundation decreases, but the extra column's own load is transferred to the foundation as an extra. In this case, should the height be too high?
 
Let's assume that we can carry the building load to 10 columns or 5 columns in 2 systems with all the same parameters. (let's say the total load is 500 tons) 50 tons per column in the 1st system, we will carry 100 tons per column in the 2nd system and we will transfer it to the foundation. Since the system is Raft, our punching environment is the same in every column (I assume the column dimensions are the same and I take into account the situation with the necessary console protrusions). will be. ie in system 1, less base height will suffice. I don't think it could be more clear. good work
 
In such matters, it would be better to model different systems and examine their results and make your own interpretation. I think it would be more correct to share the points you could not comment on here (under the Construction>Civil engineering section of the forum). For comparison, you can consider the suggestion of Saridurmus. The simplest way to interpret the results is the reinforcement density. For example, if the reinforcement range you use is very frequent, you may think that there is a problem in the size of the foundation. Good work.
 
Thank you for your explanations..you explained it very clearly. I guess it will be more ida ii if I make an application..
 
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