What is the purpose of reinforcing the slab
Reinforcing frame is a necessary element of the foundation slab. However, many builders neglect this step, believing that the concrete itself can withstand loads. To understand the question of why it is necessary to reinforce the foundation, you need to know what problems this element solves. In particular, we are talking about the following:
- Reinforcing framework makes the base stronger, which allows it to withstand loads more than a slab of ordinary cement.
- Pure concrete is characterized by high compressive strength, but it cannot withstand bending. Metal rods do not allow the concrete slab to bend from the uneven pressure. The result is less risk of uneven shrinkage of the house.
- The reinforcing frame prevents the concrete slab from deforming as a result of soil heave and movement. In addition, the reinforced foundation is not afraid of temperature extremes and groundwater. Consequently, one can draw a conclusion: reinforcement will increase the service life of the foundation and the entire building.
Creating a reinforcing frame is regulated by special documents, which specify the recommended rules and sizes of fittings.
What does the armored belt do??
The foundation slab is subjected mainly to tensile loads from the weight of the building, furniture, tenants, wind and snow. However, there are also compressive forces. Concrete works exclusively in compression, and this material cannot withstand such loads. This is why reinforcing meshes are placed in the bottom of the slab at the bottom edge of the slab to compensate for compression. In the upper part there is a second mesh, which absorbs the tensile forces.
How to Calculate the Reinforcement for a Monolithic Slab.
Peculiarities of foundation reinforcement
In contrast to the reinforcement of the slabs, the laying of reinforcement in the foundation slabs must be carried out in an uneven order. In order to provide maximum reinforcement of the areas under increased load, the bars should be laid taking into account the level of penetration in a particular place of the slab. The exception is a thin foundation (no more than 150 mm), laid under light structures. in such cases, the layout is carried out in the form of a grid.
In residential construction the thickness of the foundation, as a rule, varies in the range of 20-30 cm. and depends on the weight of the structure and the properties of the soil. In order to ensure maximum possible reinforcement, the reinforcement should be laid in two layers, on top of which a protective concrete layer that prevents corrosion should be provided.
| How to calculate the amount of rebar for the foundation. Types of foundations.
How to calculate the amount of reinforcement for the foundation. Foundations types.
The amount of reinforcement for the foundation is calculated on the basis of the type of foundation and its shape. Depending on the calculated loads and the bearing capacity of the soil, the type and size of this foundation is determined.
On a site with soils where groundwater is close, there are waterlogged areas, bogs, potholes, a slab foundation will be optimal. The slab foundation is shallow, any change in the ground for the foundation is distributed
throughout the slab of reinforced concrete, which prevents deformation of the foundation and the walls of the building. The structure will not have cavities or bends during the winter.
Monolithic foundations for buildings serves as a floor for the ground floor. For a one-story building, a slab thickness of 20. 30 cm is enough, for a two-story or three-story. 40. 50 cm. The slab foundation is the most expensive of all options, and is used in extreme cases. But its advantages are the highest load-bearing capacity and ease of construction.
Calculation of the slab foundation, rebar and binding wire.
For plate foundations ( slab foundation armature ) periodic rebars of A3 class are used, if wire-bonding of rods will be used. When using electric welding, it is worth using reinforcement of A500C class. The foundation is reinforced with 10 mm. 12 mm rebars. The diameter of the reinforcement for the foundation affects its quality. The thicker the rebar, the stronger the foundation will be. over, the more is the weight of the building, the stronger should be the foundation. When building a heavy house on a weak soil, the 14mm-16mm metal rebar is needed. In the construction of a wooden, panel house smaller diameters of fittings are used. Reinforcement for construction of the foundation is laid in a grid with window size of 20×20 or 30×30 cm.
Consider the foundation of an 8×12 m building. If the size of the mesh of the reinforcement laid with a spacing of 20 cm, then we calculate as follows:
(8/0,2 1) (12/0,2 1) = 102 bars (41 pcs of 8 cm and 61 pcs of 12 cm).
Т. к. there are two reinforcement belts in the slab foundation: the upper and the lower one, then the resulting number of bars should be multiplied by 2.
The upper mesh is connected to the lower mesh, the longitudinal bars are connected to the transverse. The number of connections is considered as follows:
The distance of the frame to the surface of the slab. 5cm, the slab itself is 20cm thick. To connect the bars, you need a length of bars:
Length of whips to connect: 25010.1 = 250.1 m.
Thus, the total amount of reinforcement needed for the slab foundation of this building is:
How to knit rebar for the foundation. To bind the rebar, use binding wire, folded in half, length 15 or 30 cm (0.15 or 0.3 m). Binding of annealed wire is carried out using special hooks.
The rods are tied twice: the longitudinal rods are joined to the transversal rods and then to the vertical whips. Consider the number of seats on the top chord and the bottom chord = 25012 = 5002 pcs. The total amount of binding wire is determined by the number of joints multiplied by the number of knots in each joint and by the length of the wire section per knot: 500220.3 = 3001.2 m.
The strip footing of the reinforcement. Foundation design.
The strip foundation for the house is a fairly common type of foundation, which is reliable and easy to make. It is used for all kinds of buildings and structures: from wooden country houses and bath houses to monolithic buildings. The strip foundation can be either precast or monolithic. Monolithic. it involves binding the frame made of rebar for the foundation and pouring concrete on it, thus achieving the integrity of the foundation. The prefabricated foundation is made by fixing reinforced concrete blocks, cement and strip foundation reinforcement. Depending on the bearing capacity of the soil and the weight of the building, strip foundations can be shallow and deep. For the building to be more stable, the width of the foundation walls must exceed the width of the building walls by at least 10 cm, and the foundation is made in the form of a trapezoid, widening towards the base.
The work of the armature in the foundation. What kind of rebar is needed for the foundation. In order to reduce transverse loads, to minimize transverse deformation of the foundation, smooth rebars of A1 class may be used as vertical and transverse whips. The longitudinal bars should be corrugated reinforcement, which provides the best adhesion to the concrete. In the construction of a low building mostly 10. 12 mm diameter rebars are used. Longitudinal bars are laid at the top and bottom of the strip foundation at a distance of 5 cm from its surface.
Монолитная плита для дома. Подготовка и заливка-Monolithic slab for home preparation and pouring
Armature for a strip foundation calculation
If the width of the foundation is 40 cm, 4 longitudinal bars, two per strip, are sufficient. If the building is built on movable soil, the weight of the building is greater, or the width of the foundation is needed more, then 3 or 4 bars in each belt are used.
Let’s calculate the foundation of a building of size 68 m with two interior walls. The foundation is 50 cm wide and 180 cm high, the distance between the reinforcing bars is 5 cm from the surface of the foundation. The foundation is reinforced with six longitudinal bars of corrugated reinforcement. Cross and vertical bars shall be installed in 0.5 m increments. Smooth rebar. 6 mm in diameter.
The length of longitudinal rods will be: 426= 252 м.
The length of smooth reinforcement A1 for each joint = (50-5-5)2 (180-5-5)3 = 590 cm = 5.9 m.
Армирование фундаментных плит. Ленточные фундаменты (Reinforcement of monolithic foundation slabs)
Tying rebar for the foundation. The connection has 6 intersections, which require 12 pieces of binding wire. Take 30 cm of wire = 0.3 m.
Total wire will be needed: 120,385 = 306 м
A post foundation for a house is a system of posts located in the corners and at the intersection of walls, under heavy beams and other elements of the building’s heavy load. This foundation is used for buildings with lightweight walls, for deep foundations, in cases where the soil gives a smaller building settlement than in the construction of strip foundations, in cases where you want to avoid the effect of low temperatures on the structure. Design of a pillar foundation. For greater stability of the foundation, for the device supporting part of the basement between the columns is built rover. strapping beams. If the distance between the columns is 1.5. 2.5 m, the column grill is a reinforced lintel. For larger spacings, the foundation rostrum will be represented by a rand beam. a monolithic or prefabricated reinforced concrete beam. Pillar foundation type is erected low-depth and non-depth.To minimize the risk of frost heave, the posts are made with a minimum cross section. When building a pillar foundation of buildings made of stone or brick the walls are erected with an extension to the bottom., Coat the foundation surface with such resins and compounds that reduce the friction of the ground.
Foundation installation reinforcement. Foundation bracing. The columns are reinforced with longitudinal reinforcement of 10 to 12 mm in diameter, placed vertically and encircled with clamps or annealed wire. The vertical struts are made of periodic (corrugated) rebars and the horizontal struts (to link the vertical struts) are made of smooth material. The vertical column consists of 2 to 6 bars and is tied at the height of the column about 50 cm.
Pillar foundation rebar calculation. The calculation of the column foundation.
For the column with a diameter of 50 cm and a length of 2 m taken 4 bars of 12 mm corrugated reinforcement. The bars are tied at a distance of 20cm=0.2m from each other with smooth rebar 6mm at 4 points.Total of 50 columns. Each horizontal bar is attached to 4m vertical.
For the column we need: Fluted rebar = 2m4pc = 8 m; plain rebar = 0.244 = 3.2 m.
How much rebar for the foundation. Thus, to create 50 posts you need: periodic: 8m 50pcs = 400m, smooth rebar: 3.2 m 50pcs = 160m
Tightening the rebar. For tying horizontal bars you need a tying wire (in 30 cm pieces):
0.3m44= 4.8m. For total quantity: 4.8 m 50 studs = 240 m of wire.
Calculating the cost of reinforcing for the foundation
On our site you can easily find your own theoretical weight of one meter of reinforcement and rebar price per ton of corrugated and plain reinforcement. Practically the weight of the rolled product may be different from the tabulated data. Determining what kind of reinforcement for the foundation you will use, our managers will help you to calculate the reinforcement for the foundation price per one stick, reinforcement price per meter and the total cost of required quantity. By yourself you can calculate the approximate calculation of rebar for the foundation reinforcement by the following formula:
(amount of reinforcement in meters weight of one meter long weight of one meter long weight of one ton of reinforcement)/1000kg.
Monolithic slab foundation
A monolithic slab foundation is nothing more than a slab of concrete that has a flat or ribbed shape, containing reinforcement inside, which is called reinforcement. This type of foundation is most often used on weak eroded soils for the construction of not very heavy buildings or the construction of heavy stoves and fireplaces, as well as under heavy stationary equipment
This calculator allows you to calculate for monolithic solid foundation:
- Concrete volume for pouring the slab.
- Necessary amount of materials for concrete.
- The amount of planking needed to make the formwork.
- The approximate cost of all building materials.
- The reinforcement of the foundation slab depends on the geological conditions and the design.
Material calculator for monolithic foundation slab
Online calculator to calculate the approximate cost and the required amount of materials for the monolithic foundation slab.
The main advantages of the monolithic slab foundation are:
- high load-bearing capacity;
- the ability to resist shifting and swelling of the ground;
- simplicity of construction;
- Good ability to resist ground and melt (surface) water;
- the possibility of building a basement protected from meltwater;
The main advantages of the monolithic slab foundation:
- high load-bearing capacity;
- ability to resist ground displacement and swelling
- ease of construction;
- good ability to resist ground and melt (surface) water;
- the ability to build a basement protected from melt water;
Plate foundations are good when construction is carried out on sandy pads or highly compressible, heaving soils. Due to the fact that the monolithic slab covers the entire area of the building, such a foundation is not subject to ground displacement. slab foundation. a kind of shallow deepened strip foundation. is either a monolithic slab or a reinforced concrete grid for the entire area of the building. This foundation is used to build a cottage (especially of cellular concrete blocks), On heavy heaving, bulk and weakly bearing soils it is possible to arrange so-called floating foundations of solid or lattice monolithic reinforced concrete slabs.
The disadvantage of a slab solid foundation:
A monolithic solid foundation, especially a sunk foundation, can add up to 30 to 50% of the cost of the house box. If the raft foundation is shallow, the cost of concrete and fittings is compensated by the ease of construction, if the raft foundation is embedded, then in addition to having a large mass of concrete will have to bring a significant amount of sand and gravel for construction of the pillow and backfill, hire of equipment for the construction of excavation and other costs often exceed a reasonable proportion (20% of total cost of the box).
Synonyms: slab foundation, slab foundation, monolithic slab foundation, foundation
Online calculator of the slab foundation
The calculator allows you to roughly calculate the amount of building materials for the slab foundation of reinforcement, concrete, boards for lining, waterproofing, sand and gravel for the cushion, to compare with the construction estimate or quickly calculate how many to order materials if you build without a project. Do not have any illusions that by using the online calculator you can calculate the foundations according to the loads, to do this you need at least to make a geological survey and have the project of your house in hand. For such calculations, please contact the designers.
the material of the house the choice of material does not affect the calculation, but only displays in the calculation table the recommended mesh pitch of the slab reinforcement. In any case, the cell pitch must be calculated by the designer of the house, this value is given for reference.
Working armature diameter is the diameter of the main working armature (mesh) of the foundation from your design.
Working armature cell spacing The distance between the rows of working armature.
The diameter of the cross bars is the diameter of the rebar that separates the lower and the upper layers of the foundation (spider reinforcement).
The recommended diameter of the working armature depends on the greater value of the length and width of the slab. From 0 to 3 meters, the recommended diameter = 10 mm, from 3 to 10 meters diameter = 12 mm, from 10 to 20 meters diameter = 14 mm. The value is for reference purposes only.
Recommended diameter of cross bars if the height of the slab is less than 30 cm, diameter = 8 mm, if the height of the slab is greater than 30 cm, diameter = 10 mm. The value is for reference only.
The recommended mesh size of the working reinforcement depends on the house material. For reference purposes only.
If the height of the slab is less or equal to 15 cm, the number of layers (meshes) = 1, if the height of the slab is greater than 15 cm, the number of layers of reinforcing bars = 2.
Minimum lap of working rebar, when joined in a single row = 40 multiplied by the diameter of the working rebar.
The length of the reinforcement is calculated by taking into account the reinforcement under the walls, one row of reinforcement is added on the edges of the foundation (the cell pitch is half of the given one), the reinforcement under the internal walls must be taken into account.
The number of stands is calculated at a density of 2 pieces per m². Reinforcements for buttressing are U-shaped braces for buttressing (see picture below). figure below):
Here you specify only the height (width) of boards for the formwork itself and for vertical supports with a spacing of 0.5 m. The length of all boards is assumed to be 6 m. The thickness of the boards of the formwork is taken equal to 40 mm, the thickness of boards for supports is taken 50 mm. The length of the spacers is not calculated, i.e.к. not all are used.
Release of the pillow for the foundation pillow is always slightly wider than the slab, usually 20-30 cm, sometimes the pillow is made immediately under the blind area about 1 meter wider than the slab.
The cost does not include concrete for the underlayment, geotextile and waterproofing, as these elements are not strictly mandatory in the construction of a slab foundation, and not everyone does them.
If you notice an error in the calculator’s work, write about it in the Комментарии и мнения владельцев, we will try to fix it as soon as possible. If something is not clear how it is calculated also please contact.
A poured foundation is a monolithic foundation that gives your building stability and durability. Reinforced concrete slab, which is laid under the entire area of the building, serves as a reliable support for a residential house or farm building. Minimum amount of excavation work, low coefficient of pressure on the ground, and ease of arrangement are the objective advantages of the monolithic slab, the key element of the foundation of this category. Professional reinforcement of the foundation slab guarantees the foundation durability and resistance to solid mechanical loads. Competent calculation of slab foundation will help you to quickly and accurately perform the online foundation calculator of cast-in-place slab foundation.
The advantages of the online calculator for the slab foundation
- Calculates the foundation slab, taking into account all the technical and performance characteristics of the concrete, formwork and reinforcement cage.
- Saves you time and effort in developing a successful construction strategy as well as in drawing up an estimate for the arrangement of a slab foundation.
- 2D and 3D visualization options allow you to visually evaluate the adequacy of calculation operations in real time, and if necessary make appropriate corrections to the project.
How to Calculate Quantity of Steel in slab.
Calculation of reinforcement for a monolithic slab
- Definition of the minimum diameter of reinforcement mesh elements, which must comply with the SNiP rules.
- Calculation of the minimum allowable cross-section of the vertical reinforcement cage bars.
- Specifying the average mesh size of the reinforcement mesh, as well as determining the size of the overlap.
- Calculation of the number of rows, the diameter of the collars, as well as determining the total weight of the reinforcing cage, taking into account the overlap.
Additional functions of the online calculator
- Calculating the number, length and thickness of formwork boards in accordance with GOST R. 52086-2003.
- Determining the metric characteristics of the plate, its sole and sides to calculate the amount of insulation.
- Calculation of the proportion of sand, cement and crushed stone in the handmade concrete that will be needed to form a slab foundation.
Maximally simplify the process of calculation and measurement operations today. Use the free online slab foundation calculator right now!
Rules for choosing reinforcement
Before selecting the material, it is important to find out the level of the planned load. For this, the foundation is selected and the soil is analyzed.
Next, the calculation of the reinforcement section. For monolithic slab choose the diameter of the rods over 10 mm. It is important to keep in mind the degree of load on the ground.
If the soil is weak, thicker reinforcing bars are used, for example, from 12 mm. As for the corners of the structure, then rebar up to 16 mm can also be used here.
Reinforcement comes in several types depending on the features:
- Longitudinal reinforcement prevents the structure from stretching and vertical cracks. When exposed, the reinforcing bar takes some of the load and distributes it evenly across the entire surface of the slab.
- Transverse reinforcement protects against the appearance of cracks when stresses are applied to the supports.
The foundation, made in the form of a monolithic slab (foundation slab), is the most expensive of all types of foundations. But despite the high price, due to the significant cost of the concrete mixture and insulation materials, this type of construction is one of the most popular among private builders. Monolithic foundation has the highest performance indicators, it is suitable for complex soils, it is not afraid of high groundwater level, frost heave forces and can withstand loads from houses made of heavy building blocks.
KALK service.PRO offers you an easy and efficient online foundation slab calculation calculator for free. You’ll get a detailed bill of materials (rebar, concrete, crushed stone, cement, formwork) and the cost of the entire structure. We plan to add foundation drawings and adaptive 3D-model shortly. Add our site to bookmarks!
The correct calculation of the foundation directly affects the longevity of your building, so it is important to use only reliable calculation programs. Our service uses only current regulatory and reference data, the algorithm of work is based on the position of SNiP 52-01-2003 Concrete and reinforced concrete structures, SNiP 3.03.01-87 Bearing and enclosing structures and GOST R 52086-2003 Shuttering. Terms and Definitions
Our calculator to calculate the slab foundation will help to calculate the necessary amount of materials and costs for future construction quickly, easily and accurately!