Good afternoon, dear guests and subscribers of the "Build for myself" channel!
Yesterday I was in a situation and faced a very common delusion of people. A friend chooses a house for the purpose of its further purchase and asked me to drive along with him several properties. We were not alone, there was also an agent from the real estate office who was trying to foist on him almost every house we looked at.
Every time, when inspecting a house, the realtor focused not on the houses as such, but on the foundation: "look what a solid foundation it has been worth for 10 years and at least something" or "wow, such a foundation and a five-story building will stand ". I wonder how he visually determined what the foundation could withstand and what could not, and I had to endlessly tug at it, they say, if you don't know why you are talking nonsense ...
To questions about the depth or width of the foundation, no one, including the owner, could answer us, and even worse, when trying to get away from answers to direct questions - they lied and got confused in the testimony, not understanding what they were talking about, but just to chat without stopping and praise the house, with only one purpose - sell and make money on it ...
"Such a foundation will withstand a five-story building" is a fundamentally erroneous conclusion, since the main function of the foundation is not to keep, but to distribute.
From time immemorial, the main task of the foundation was to transfer the load of a higher structure to the foundation, while not violating the bearing capacity of the foundation itself. And the base is always the continental soil, which lies directly under the foundation. In fact, it is the soil that holds the whole house, but not the foundation.
Therefore, building codes are named exactly that. "Foundations and Foundations".
The main function of the foundation is to tie all the nodes of the structure together in order to uniform LOAD TRANSFER to the ground. And only because of thisfoundations are selected based on the composition of the soil and its characteristics directly at the building site.
For example, we have a house that has a certain own weight and creates a pressure on the base equal to 5 kg / cm 2. We also have soil with a bearing capacity of 3 kg / sq. Cm. (picture below)
We see that the load from the house is greater than the soil can carry and it is quite logical that we need to distribute the rest of the load, otherwise the house will shrink. It is for this purpose that the foundation stands. By increasing the area of its bearing on the ground - we distribute the weight of the house, taking into account the peculiarities of the base (the picture below is an increase in the sole)
Thus, the foundation acts as an intermediary between the structure and the foundation. He perceives and transfers all the load to the bearing soil. Of course, strength requirements are imposed on the foundations so as not to crumble under the weight of the building for one and only goals: to ensure the integrity and safety of the structure. And in order to do this and eliminate deformations at home, you need to ensure:
- no freezing of soil under the base of the foundation;
- correct calculation of the bearing area;
- reinforcement of the concrete structure of the upper and lower belts in case of soil shrinkage or heaving.
That's all, thank you for your attention!
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