How to calculate the cubic capacity of concrete, firewood, logs?

Sometimes you have to remember school lessons in our adult life. It comes to geometry. Such concepts as “volume”, “surface area” are often recalled during repair or summer house construction.

Recall how to calculate the cubic capacity of various building structures or materials so as not to overpay for excess material on the one hand and not to stop the construction process for delivering the missing amount on the other. In fact, there is nothing complicated in calculating the volume of basic geometric shapes. There are peculiarities in calculating the volume of bulk materials, building materials such as gravel, gravel, as well as chopped firewood and firewood in logs or logs. But first things first.

How to calculate the cubature of a flat building structure?

The formula for calculating the volume is universal:

V = H ∙ L ∙ B, m ³

Where:

H is the height of the concrete layer (thickness), m;

L is the length of the structure, m;

B - width, m.

The procedure for calculating the volume of the box is shown in the figure.

To get started, take a simple example. It is necessary to fill in a concrete porch of known sizes, consisting of two rectangular steps. How to calculate the cubic capacity of concrete needed to make this structure?

For ease of calculation, it is convenient to divide the structure into two parts 1 and 2. Both of them are nothing but parallelepipeds with known sizes. The width of both parts is the same and is 1 m, the thickness is also equivalent - 0.2 m. The length of the first (lower) step is 1.2 m, the upper one - 0.8 m

Volume of the upper stage:

V ₁ = H ₁ ∙ L ₁ ∙ B ₁ = 0.2 ∙ 0.8 ∙ 1.0 = 0.16 m ³

Volume of the lower stage:

V ₂ = H ₂ ∙ L ₂ ∙ B ₂ = 0.2 ∙ 1.2 ∙ 1.0 = 0.24 m ³

The volume of the entire structure

V = V ₁ + V ₂ = 0.40 m ³

The shape of some building structures at first glance seems very complicated. But do not despair, because all of them, even the most complex forms, can be divided in a similar way into simple geometric shapes, find the cubature of each separately and then summarize.

Foundations

The main types of foundations used in private construction:

• tape;
• pile;
• pile with grillage;
• plate.

A slab foundation is, as the name implies, a slab - a parallelepiped, the volume of which was calculated above. Recently, it has been steadily gaining popularity, with proper construction it is characterized by phenomenal stability on complex clay soils and loams.

Consider how to calculate the cubature of the foundation of the tape. The calculation algorithm is as follows: first, the perimeter of the foundation is calculated, which is multiplied with the width and height of the tape. An example of a strip foundation for a small building with dimensions in the plan of 5 by 3 m in the figure.

Foundation perimeter:

P = 5 ∙ 2 + 3 ∙ 2 = 16 m

Then the volume of the structure:

V = 16 ∙ 0.4 ∙ 1.5 = 9.6 m ³

And how to calculate the cubic capacity of the base, consisting of cylindrical piles? We calculate the volume of one cylindrical pile, shown in the figure, 2.1 m long and 0.26 m in diameter. So, the cylinder volume is:

V = π ∙ R ² ∙ H,

Where:

π is a universal number equal to 3.14;

R is the radius of the circle, equal to half the diameter;

H is the height of the pile.

In our example:

V = π ∙ R ² ∙ H = 3.14 ∙ (0.26 / 2) ² ∙ 2.1 = 0.111 m ³

Since the foundation consists of several piles, the obtained value of the volume of one must be multiplied by their number.

The pile foundation with grillage is a symbiosis of the two types discussed above. The grillage is nothing more than a tape, below which piles are located. It is necessary to calculate the cubic capacity of grillage (tapes), then the volume of the pile foundation and the obtained values ​​to summarize.

And how much do you need to buy?

However, the owner is not so much concerned about the exact volume of a building structure, but how many and what materials need to be purchased. How to calculate the cubic volume of crushed stone, sand and cement, necessary for filling the mold, if its volume is known? The special tables developed by builders will help with this.

The composition of the components for the preparation of concrete grade 300 (foundation):

However, at a construction site, as a rule, they do not use weights, the following table is designed specifically for working with a concrete mixer:

Lumber

Such widespread timber from timber as timber, board, lath have a geometric parallelepiped shape, and the volume of each product separately can be easily calculated. This applies to calculating the need for material for the construction of a greenhouse or frame arbor.

However, it is difficult to imagine what the calculation of the required number of floorboards in the cottage will turn into if we calculate the location of each piece of wood and its volume. But then how? Calculate the cubature of the board by a simple formula:

V = S ∙ h ∙ 1.05 / 1000

Where:

S - floor area of ​​the finished premises, m ² ;

h is the selected thickness of the floorboard, mm;

1.05 - coefficient of cutting.

Log houses

Despite the rapid development of the construction industry, the annual appearance of the latest materials with first-class strength, heat-insulating and other properties does not even think of giving up wooden log cabins. On the contrary, the construction of houses and baths made of wood is only gaining popularity. Let’s figure out how to calculate the cubic capacity of a log needed to build a log house.

Before the calculation, as a rule, the plan of the perimeter of the building is known, and therefore the length of the logs. In order to calculate their number, you need to know the number of crowns, which depends on the height of the wall and the diameter of the round timber. In construction, not the entire height of the log is used, part of it “eats” the groove. This is clearly seen in the diagram.

Further, knowing the number of logs and their diameter, the calculation is done similarly to the calculation of the cubic capacity of cylindrical piles.

Firewood

Although pipeline gas is slowly coming to the most remote corners of the country, wood heating will most likely not soon lose its relevance. Lately most often, firewood has been brought ready, that is, sawn and chopped. But if they were brought in a cubic meter box per meter per meter, this does not mean that the customer must pay for a cubic meter of fuel. The calculation is made for the volume of the tree, not air. Consider how to calculate the cubic capacity of firewood purchased and delivered to the customer.

In fact, it is impossible to calculate exactly the cubic capacity of firewood, you can only roughly estimate how much fuel is in the body, stack, etc. For this, the geometric volume in which the stored or dumped heating oil is located needs to be multiplied by a correction factor.

If the firewood is tightly stacked, this coefficient is 0.71-0.85, but chopped, thrown in bulk in the body occupy only 0.29-0.35 of the total volume.

Firewood trailer

But firewood is not carried in the correct containers. How to calculate the cubic capacity of fuel delivered to the site in conventional transport. This is usually a body or trailer with a slide. Well, let's calculate the volume of this slide. Imagine that the firewood is in the body of a rectangular car, dimensions in the plan L to B and height H. Above the sides of the body stands a slide of height h.

The formula for determining the net volume of firewood in the body will look like this:

V = k ∙ L ∙ B ∙ (H + h / 3), m ³

L - body length, m,

B - body width, m;

H is the height of the sides, m;

h - the height of the "hill", towering above the sides, m;

k is the volume coefficient.