Good afternoon, dear guests and subscribers of the "Build for Myself" channel!
Six months ago, on my channel, I told a story about how my neighbor was nearly ruined his house. With equal diagonals, the corners of the foundation of the house were not straight, and the opposite sides differed from each other by 11 cm. (If you are interested, the article HERE).
In fact, most people are used to thinking that when building the axes of a house, equal diagonals are characteristic only of rectangular quadrangles, but unfortunately this is not the case. Therefore, some builders are confused, not understanding how it happened, the diagonals are equal, and the layout of the brick does not work.
An uneven foundation can lead to the consequences indicated in the figure when the vertical the plane of the brick wall does not coincide with the plane of the foundation, and it is not possible to align the structure in another way comes out.
Hence the problems with the plinth lining, and most importantly, with the performance characteristics. buildings, in case the wall hangs from the basement more than permissible for the used wall material.
Therefore, it is better to measure 7 times and dig out once! :-)
I will give several examples of non-rectangular quadrangles with equal diagonals and I will mark the borders of the rectangle with a dotted line in order to see the deviation of the sides and angles for clarity. These include:
1. Isosceles trapezoid
This option is most often obtained. Deceiving by the fact that the sides and diagonals are equal. Therefore, no one thinks that it can be a different figure than a rectangle. Indeed, on the ground, on a large territory, this is not visible without control measurements.
2. Irregular quadrilateral
Neither angles nor sides are equal, but diagonals are equal!
And there are a great many similar geometrical figures similar to figure # 2. Take two identical matches, cross them and move them like two identical diagonals and you will get many shapes ...
Why can both options take place on a construction site?
It is corny, but this is not only ignorance of geometry, but even an experienced builder can be inattentive.. The person could be distracted. It usually happens like this:
With the help of laces, a rectangle is built exactly with the design dimensions. Stakes are hammered in the corners. Since all sides are built and equal to the design data, we proceed to check the diagonals. By measuring, we obtain the inequality of the diagonals with a deviation of, say, 7 cm. Of course, it is impossible to make the correct figure on the ground the first time. We begin to level the corners to achieve equal diagonals. Done! The diagonals are equal!
It's hot outside, stood in the shade, sipped some water, called his wife, and had lunch. - What are the diagonals are equal? - Equal! -Aah, well, then we do the castoff and dig!
Anyway, there are a lot of factors to bring down the builder. Already the master flew out of his head that he was achieving equal diagonals and shifting the corner stakes even by 1-2 cm. we have already obtained the inequality of the sides, which corresponds to any of the variants of the figures.
Of course one can say "rave"one might say "yes, all builders know the Egyptian triangle 3-4-5", but the fact remains that thousands of houses have been built and will still be built with huge deviations due to carelessness. This also includes cases using Chinese tape measures that stretch 1 cm. with a length of 3 m.
The second, very common moment, when all measurements are made with an accuracy of a centimeter, and as a result, an uneven foundation is obtained - work outside the horizontal plane. The surface of the earth has a slope, and even if the axes are built and the laces seem to be stretched evenly, then when projecting onto a horizontal plane, we get the wrong result.
Personally, I was faced with a situation when excavators, throwing the soil out of the trench, knocked down a stretched lace, thereby moving the axis by 3.5 cm. Hit the thread, moved the wall border, and dug it out incorrectly. And this was noticed only during the installation of the formwork.
Therefore, I always recommend carry out control measurements!
That's all, I think you liked the article! Thanks for attention!
Concrete in the ground. Does cement laitance leave concrete and how does the reaction of cement and water take place?
The load from the house on the ground is almost the same as the load of a person on the ground (Interesting fact)
Houses with the same usable area: one-story 12x12 and two-story 9x9. Which one is cheaper to build?