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Foundation

August 12, 2017 18:06

The calculation for the foundation reinforcement

Calculation of reinforcement for the foundation - an important stage in its design, so it should be carried out taking into account the requirements of SNIP 52-01-2003 selectable valve class section and the required number.

To begin to understand why in a monolithic concrete foundation necessary metal fittings.Concrete industrial strength after they set different high compressive strength, and a much lower tensile strength.Not reinforced concrete base with heave susceptible to cracking, which can lead to deformation of the walls and even the destruction of the entire building.

The calculation for the foundation reinforcement

reinforcement calculation for the foundation

reinforcement calculation for the foundation slab

slab foundation is often used in the construction of cottages and country houses, and other buildings without a basement.It is a concrete slab, reinforced rod in both perpendicular directions, at a thickness of more than 20 cm foundation mesh is performed in the upper and lower layer.

Prior to the calculation necessary to determine the brand of rebar.For a slab foundation, performed on solid ground nepuchinistyh where the horizontal shift is negligible probability of building, may be used ribbed rebars class A-I with a diameter of 10 mm.If the ground is weak, heaving a building stands on a slope - bar must be selected at least 14 mm in diameter.For vertical connections between upper and lower reinforcing mesh sufficiently smooth rod with a diameter of 6 mm class A-I.

Wall material is also important, as the load of a building is significantly different from the frame or wooden houses and buildings made of bricks or concrete blocks.In general, for small lightweight structures may be used 12.10 mm diameter rod, for the brick or block - valves 14-16 mm in diameter.

distances between the bars in the grid are typically 20 cm in both longitudinal and transverse direction.This means that a 1 meter length of the house is necessary to lay 5 rebars.Between a perpendicular intersecting rods connect the soft annealed wire with a hook for knitting or knitting gun.

The sample is installed rebar for the foundation

Sample installed rebar for the foundation

Calculation example:

house of concrete blocks, mounted on a foundation slab 40 cm thick on srednepuchinistyh loam.Dimensions Home - 9h6 meters.

  1. Since the thickness of the foundation is significant, requires two meshes, as well as vertical links.Horizontal grid structure to block is performed on the ground srednepuchinistom reinforced rod with a diameter of 16 mm, the vertical - of smooth 6 mm diameter rod.
  2. number of bars of longitudinal reinforcement is calculated as follows: length of most of the foundation is divided into lattice spacing: 9 / 0.2 = 45 longitudinal reinforcement bars 6 meters long, and the total number of rods equal to 45 · 6 = 270 m Similarly
  3. find the number of rods.for cross-linking: 6 / 0.2 = 30 bars;. 30 · 9 = 270 m
  4. Total rod into two reinforcing mesh is:. (270 + 270) · 2 = 1080 m
  5. vertical connection has a length equal to the height of the foundation.Their number is found by the number of intersections of the longitudinal and transverse reinforcement rods 45 · 30 = 1,350 units.Their total length is 1350 · 0.4 = 540 meters.
  6. Thus, the need to perform a foundation:
  7. 1,080 meters rod class A-III D16;
  8. 540 meters rod class A-I D6.
  9. to GOST 2590 find its mass.Running meter rod D16 weighs 1.58 kg;meter bar D6 - 0,222 kg.Calculate the total weight of 1080 · 1.58 = 1706.4 kg;540 · 0.222 = 119.88 kg.

    The total cross-sectional area of reinforcement rod

    sumarno sectional area of ​​the valve stem

  10. calculation binding wire depends on the tool used.When knitting crochet average consumption of wire is 40 cm per connection.The number of connections in the same row is equal to 1350 in two - wire 2700. Consumption will be 2700 · 0.4 = 1,080 meters.Weight of 1 meter diameter wire d = 1,0 mm is 6.12 g for reinforcement knitted foundation required 1080 · 6610 = 6,12 g = 6,6 kg of wire.

reinforcement calculation for strip foundation

in strip foundation the main burden falls on the gap along the belt, that is directed longitudinally.Therefore, for the selected longitudinal reinforcement bars with a thickness of 12-16 mm depending on the type of ground and the wall material, while the transverse and vertical links are allowed to take a smaller diameter rod - from 6 to 10 mm.In general, the calculation principle is similar to the calculation of reinforcement of the foundation slab, but a step of reinforcing lattice selected 10-15 cm, as the efforts to strip foundation gap can be much larger.

Sample installation fittings for strip foundation

fixture shall sample for strip foundation

Calculation example:

Strip foundation of wooden houses, the width of the foundation 0.4 m, height - 1 meter.Dimensions house 6x12 meters.The soil - sandy loam distending.

  1. to perform strip foundation is required to arrange two meshes.Lower mesh reinforcement prevents tear tape when the foundation subsidence, the upper - with its swelling.
  2. grid spacing of 20 cm is selected. For the foundation tape device must be 0.4 / 0.2 = 2 longitudinal rods in each layer of reinforcement.
  3. diameter longitudinal rod to the wooden house - 12 mm.To perform the two-layer reinforcement of the two long sides of the foundation must be 2 · 12 · 2 · 2 bar = 96 m.For
  4. short sides 6 · 2 · 2 · 2 = 48 m.
  5. For crosslinking select bars with diameter of 10 mm.. Step styling - 0.5 m
  6. calculate the perimeter of the tape base (6 + 12) = 2 · 36 meters.The resulting perimeter divided by stacking step: 36 / 0.5 = 72 cross-bar.Their length is equal to the width of the foundation, therefore, the total number of 72 · 0.4 = 28.2 m.
  7. to vertical links also use a rod D10.The height of the vertical reinforcement is equal to the height of the basement - 1 m number is determined by the number of crossings by multiplying the number of transverse bars on the number of longitudinal:. 72 · 4 = 288 pieces.With a length of 1 m total length will be 288 m
  8. Thus, to perform the reinforcement strip foundation needed:
  • 144 meters rod class A-III D12;.
  • 316,2 meters rod class A-I D10.
  • to GOST 2590 find its mass.Running meter rod D16 weighs 0.888 kg;meter bar D6 - 0,617 kg.Calculate the total weight: 144 · 0.88 = 126.72 kg;316.2 · 0.617 = 193.51 kg.

calculation binding wire: the number of connections can be calculated by the number of vertical reinforcement by multiplying it by 2 - 288 · 2 = 576 connections.Consumption of wire per connection accept 0.4 meters.Consumption of wire will be 576 · 0.4 = 230.4 meters.Weight of 1 meter diameter wire d = 1,0 mm is 6.12 g for reinforcement knitted foundation required 6,12 · 230.4 = 1410 g = 1,4 kg of wire.