Overlapping on the profiled sheet
In this case it is recommended to take a profiled sheet of H-60 or H-75 brand. They have a good load-bearing capacity. The material is mounted so that the pouring formed ribs facing downward. Next, the monolithic floor slab is designed, the reinforcement consists of two parts:
The most common variant, when the ribs are installed one rod with a diameter of 12 or 14 mm. Inventory plastic clamps are suitable for the installation of rods. If you need to cover a large span, a frame of two bars that are connected by a vertical clamp can be installed in the rib.
An anti-shrinkage grid is usually placed at the top of the slab. 5 mm diameter elements are used for its manufacture. Cell dimensions are taken as 100×100 mm.
With what and why reinforce the floor
Steel and composite reinforcement (mostly fiberglass) are used for reinforcement of floor slabs. common is the metal reinforcement A500C (in the design specification may be denoted as S500), 10 and 12 mm diameters are popular. For the main reinforcement of reinforced concrete structures only corrugated reinforcement is used to create high-quality connection of the reinforcement with the concrete. For additional elements that do not affect the load-bearing capacity of the future reinforced concrete structure, you can use smooth reinforcement A1. Modern private construction practices a combination of reinforcement, used to reinforce the monolithic slab simultaneously metal and fiberglass bars.
Regardless of what reinforcement is used, it plays the same role in the concrete gives it the necessary strength to withstand all future tensile, torsional and bending loads.
Creating the openings
To ensure the exit of utilities, the monolithic slab should be equipped with apertures. The process of designing them has much in common with the construction of reinforced concrete structures and includes the following recommendations:
- Make apertures in the grid at the desired location by bending the ends of the bars upwards;
- For large openings (30 cm) the holes are cut out from the top of the slab. and more) will need to make a border of bars, which are placed diagonally to the main direction of the grid;
- Small openings for the monolithic slab do not need to be reinforced.
Note that openings for the calculated communication unit are only made in non-cut slabs.
How to calculate the consumption of reinforcement per cube of concrete
According to SP 52-101-2003 the structure can be called reinforced concrete, if the cross-sectional area of the longitudinal steel bars is at least 0.1 % of the cross-sectional area of concrete. The maximum percentage of steel bars in the concrete is 5, at the junction of, for example, columns, this figure can be up to 10. The recommended range, is 0.5-3% of the reinforcement, of the cross-sectional area of the concrete.
Based on the structural requirements of SP 52-101-2003, the rate of consumption of reinforcement for reinforcement of reinforced concrete structures, ranges from 20 to 430 kg per 1 m 3 of concrete.
Table of valve consumption
This table calculates the weight of reinforcement required for reinforcement of reinforced concrete structures, depending on its quantity as a percentage of the cross-sectional area of concrete.
|Content of rebar, %||Weight of reinforcement per 1 m 3 of concrete, kg|
Calculation calculator of monolithic slab foundation
Using the online slab foundation calculator you can calculate the size, formwork, quantity and diameter of reinforcement, and the amount of concrete required for the arrangement of this type of foundation. Before choosing the type of foundation, be sure to consult with experts, whether this type is suitable for your conditions. Instructions to the calculator.
When working, pay special attention to the units of measurement of the entered data!
Why do we need a wireframe??
This type of building element allows a significant increase in the load per unit surface area. As a rule, such structures use metal of relatively soft density, such as iron rod, channel and other billets.
But it happens that denser and heavier material is also used to reinforce the structure, for example, angles or other rolled metals. According to their physical and construction characteristics, such reinforced concrete structures have a number of classifications, the basis of which is the strength class of reinforced concrete.
So the following classes of reinforced concrete structures are distinguished:
- Hot Rolling Design.
- Manufactured concrete structures with the use of thermal and chemical treatment.
- Thermally reinforced structure.
From these classifications and a number of strengths depend on those or other characteristics assigned to the enormous strength and stability of reinforced concrete structures in construction. For any construction material is a distinguishing characteristic is the GOST, according to which the producers of reinforced concrete structural elements roll out the material.
It is this standard that regulates the use of a particular type or strength class of reinforcement in concrete mortar. Basically, their use is inextricably linked with the concept of reinforced concrete material.
As a rule, a reinforced concrete element, whether it is a slab or a block, consists of some frame of metal reinforcement, on which there is a shell of concrete mortar. As a rule, the question of the use of one or another type of reinforcement, is quite relevant, and often, at all constant among builders and engineers.
The connection between these two specialties is quite simple. Each of them wants the building they have built to stand for as long and as strong as possible. In addition, there are their own laws and regulations established by the state standard of construction. To reinforce the structure being built, reinforcing iron bars of various strengths and thicknesses are used.
Calculation of materials for the foundation slab
Y. the length of the foundation slab X. slab width B. the total height of the foundation slab
Z. mesh length W. cell width D. rebar diameter R. Number of horizontal rows of reinforcement If you do not need to calculate the reinforcement, then leave this field empty.
The required amount of cement to produce one cubic meter of concrete is different in each case. This depends on the cement grade, the desired grade of the resulting concrete, the size and proportions of the fillers.
M. how many bags of cement per cubic metre of concrete K. Weight of one sack of cement in kilograms
T. formwork board thickness H. the width of the board L. board length
Specify the material in your region.
Do not forget to recalculate the of bulk materials in the cost by weight, not by volume. One type of shallow foundation is a monolithic foundation slab. Usually such a foundation is a monolithic concrete slab that is located under the entire area of the house. In order to absorb loads without deformations, spatial reinforcement throughout the entire volume of the slab foundation is always applied. Their construction requires a greater consumption of concrete and reinforcement compared with traditional types of foundations and is therefore somewhat more expensive.
What this program helps to calculate?
Volume of concrete for pouring the slab. The required amount of materials for preparing the concrete. cement, sand, crushed stone. The amount of board required to construct the formwork. The approximate cost of all building materials. The reinforcement of the foundation slab depends on the geological conditions and the project.
When planning the construction one should necessarily take into account the need to purchase timber for the installation of formwork. This is a structure made of boards, designed to give the desired shape to the foundation. You can perform an accurate calculation of the formwork for the monolithic slab foundation with our online calculator.
The initial data for the calculation are, apart from the parameters of the slab, the characteristics of the board to be used. The program will calculate the number and total cubature of boards needed to install the formwork. Thanks to this you can purchase the right amount of timber and determine the cost in advance.
Formwork for the slab foundation Photo from open sources
People have always tried to build their homes on a solid rock base. It was this approach that gave reliability and durability to the buildings built. And it was this that led to the design and construction on slab foundations.
A slab foundation is commonly referred to as a foundation structure for a building, which is a reinforced concrete monolithic slab located within the perimeter of the building, or, more often, slightly exceeding it.
- precast, assembled into a single slab of prefabricated factory blocks or plates;
- monolithic, made directly on the construction site and representing an integral rigid structure of reinforced concrete.
Both types of these foundations have their pros and cons, and are used under different construction conditions.
Online course Calculation of a Monolithic buildingin the LIRA SAPR 2017 software package, PART 1
Prefabricated foundation slab is constructed from prefabricated reinforced concrete slabs produced by the ZZHBI. Reinforced Concrete Products Plant. Slabs of the type may be used for manufacture:
- PD. road slab;
- PDP. road for pavement;
- PDG. road with corrugated surface;
- PDP. road with stressed reinforcement;
- PAG. airfield and mn. et al.
The prefabricated slab foundation is good at supporting the load on dry, firm and non-swelling soils. And they work best on soils with fine or coarse-clastic stone structure. For this type of foundation, it is desirable to have a shallow depth of soil freezing. That is why precast slabs are more often used for construction in the southern regions of the country, where the soil does not freeze or the freezing depth is insignificant.
But as soon as sandy loam, clay, and especially loess soils get a little wet, such as from melting snow, or prolonged autumn rains, sagging of individual plates starts immediately, and then the walls and ceilings of the house crack.
- A precast slab foundation is a huge artificial flat rock of high strength. The compressive strength of monolithic foundation is ensured by using the appropriate grade of concrete, and the bending strength is ensured by its reinforcing frame.
- The structure of the framework is made of reinforcing bars of the required diameter and steel grade, using the data in GOST 5781. It is possible to make a framework of composite materials. glass or carbon fiber. Part of the composite reinforcement is made on the basis of basalt fiber.
- On site, the steel frame is electro-welded or bound with a soft steel wire. Composite frame is only knitted with wire, just like the steel frame.
- A wireframe takes the form of a spatial framework in which the reinforcing bars are arranged in mutually perpendicular directions and form two planes in the form of horizontal grids. Its scheme is determined in the design.
- The mesh size of these meshes is calculated in the design and ranges from 200 x 200. 300 x 300 mm. Reinforcement is used with a diameter of 12. 16 mm.
The frame is installed on plastic “stools”. supports. Their height provides the exact distance from the lower and upper planes of the foundation, and is 50 mm. Frames are mounted so that the distance from their edges to the formwork was the same 50 mm. This gap during concrete pouring and compaction forms a special layer that protects the reinforcement cage from corrosion. After the concrete hardens and sets them to the strength specified by the calculation when designing the monolithic foundation is ready for construction of the building.
Builders have a common opinion that the monolithic slab foundation is suitable for any type of soil. It’s not. After all, for swampy and heavily frosty, and hence porous soils, it is better to use piles. Monolithic foundation slabs withstand weak and medium bulk soils well.