STONE AND ARM-CAMERA KOHCTPUKTII. MATERIALS FOR STONE LAYING

As stone materials from which buildings are erected, they use solid, lightweight and hollow brick, brick blocks and blocks of natural stone. Concrete blocks are used for basement walls. The most common use in construction is ceramic common brick of grades 75-125 and silicate brick of grades 75-250, as well as hollow brick grades 75-150, ceramic hollow and concrete hollow or solid stones from heavy concrete of class 50-200 and on porous aggregates of grades 25 -100, natural stones (limestone, tuffs), rubble stone for the construction of foundations and walls below ground level and soil concrete.

Solutions used to connect individual bricks or stones with each other, ensure their joint work, uniform load transfer over the masonry, and maintenance of the heat and humidity regime of the room in use. By type of binders, the solutions can be clay, lime, cement or composite (for example, clay-cement, cement-lime, etc.). The brand of the solution (compression resistance at 28 days of age) varies between 0.4-20.0 MPa and depends on the age, type of binder and hardening conditions.

The main design characteristics of strength and deformability for natural and artificial stone products and mortar binding solutions are given in table. 1 ÷ 4. '

When determining the design characteristics (Table 1 ÷ 4 ), it is necessary to consider the following ratios of working conditions γс:

a) for pillars and walls with a cross-sectional area of 0.3m2 and less - 0.8;

b) for elements of circular cross-section, not reinforced with mesh reinforcement, made of ordinary bricks -0.6;

c) for masonry compression when the solution hardens for more than a year - 1.15;

g) for laying of silicate bricks on mortars

with the addition of potash -0.85.

For the reinforcement of masonry, reinforcement of classes А-I and Вр-I is used for mesh reinforcement and AI; BP-I and A-II for longitudinal and transverse reinforcement, anchors and connections, and the coefficient of working conditions must be considered depending on the type of reinforcement γcs in accordance with SNiP 2.03.01-84.

Modulus of elasticity (initial strain modulus) for unreinforced masonry

Ео = aRu, (1)

for reinforced masonry

Ea = aa Rshu, (2)

where a and aa are the elastic characteristics of the masonry taken on the table. 3,

Ru - the average tensile strength (temporary resistance) of the masonry in compression

Ru = R, (3)

where R is the calculated resistance of the masonry taking into account the coefficients of the conditions of work of the masonry; k - coefficient equal to 2 for laying of bricks and stones of all kinds (except for large and small blocks of cellular concrete); RSu - the average tensile strength (temporary resistance) to compression of reinforced masonry from brick or ceramic stones, determined by:

For masonry with mesh reinforcement

Rshu = kR + 2 Rsn μ / 100 (4)

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For masonry with longitudinal reinforcement

Rshu = kR + Rsn μ / 100 (5)

μ = As / Ak * 100 (5 a )

where A, Ak -, respectively, the cross-sectional area of reinforcement and masonry;

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Rsn - normative resistance of reinforcement in masonry; μ is the percentage of reinforcement. The percentage of reinforcement for masonry with retina reinforcement is μ = υs / υk × 100, where υs and υk are the volumes of reinforcement and masonry, respectively. For masonry with longitudinal reinforcement μ = As / Ak × 100, where As and Ak are the areas of reinforcement and masonry, respectively. Rsn = 240; 300 and 350 MPa, respectively, for steel classes AI, A-II and Bp-I.

The value of the elastic characteristics for masonry with longitudinal reinforcement is taken as for unreinforced masonry, and for masonry with mesh reinforcement, a sk is determined by the formula

ask = aRu / Rsku (6)

The value of the strain modulus when determining stresses in the masonry in the calculations for the limiting states of the first group E = 0.5 E0 and the limiting states of the second group E = 0.8 E0; masonry shear modulus G = 0.4 E0 (E0 modulus of elasticity in compression).

Table 1. Calculated resistances to compression of all types of brick masonry and ceramic stones with slit-like vertical voids up to 12 mm wide with a height of a row of masonry 50-150 mm on heavy mortars

Brand of brick or stone

Design resistance R, MPa

With a brand of solution

When the strength of the solution

200

150

100

ten

four

0.2

null

300

250

200

150

125

100

3.9

3.6

3.2

2.6

3.6

3.3

3.0

2.4

2.2

2.0

3.3

3.0

2.7

2.2

2.0

1.8

1.5

3.0

2.8

2.5

2.0

1.9

1.7

1.4

1.1

0.9

2.8

2.5

2.2

1.8

1.7

1.5

1,3

1.0

0.8

2.5

2.2

1.8

1.5

1.4

1,3

1.1

0.9

0.7

2.2

1.9

1.6

1,3

1.2

1.0

0.9

0.7

0.6

1.8

1.6

1.4

1.2

1.1

0.9

0.7

0.6

0.45

1.7

1.5

1,3

1.0

0.9

0.8

0.6

0.5

0.4

1.5

1,3

1.0

0.8

0.7

0.6

0.4

0.35

0.25

Notes: 1. The calculated resistance of masonry to compression is taken into account taking into account

coefficients: 0,85-when applying hard (without the addition of clay or lime), and light cement mortars, as well as lime mortars under the age of three months; 0.9-for cement mortars (without lime or clay) with organic plasticizers.

2. The calculated resistance of masonry of ceramic stones with voids more than 12mm wide are taken from experimental data.

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Table 2. Calculated resistances R to compression of masonry from large concrete solid blocks and blocks from natural stone, captured or clean tesky at the height of the masonry row 500-1000mm

Brand of concrete or stone

Design resistance R, MPa

With a brand of solution

At zero strength of the solution

ten

1000

800

600

500

400

300

250

200

150

100

16.5

13.8

11.4

9.8

8.2

6.5

5.7

4.7

3.9

2.7

2.1

1.5

1.1

0.9

15.8

13.3

10.9

9.3

7.7

6.2

5.4

4.3

3.7

2.6

2.0

1.4

1.0

0.8

14.5

12.3

9.9

8.7

7.4

5.7

4.9

4.0

3.4

2.4

1.8

1.2

0.9

0.7

11.3

9.4

7.3

6.3

5.3

4.4

3.8

3.0

2.4

1.7

1,3

0.85

0.6

0.5

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Table 3. Elastic characteristic of masonry a

Type of masonry

Elastic masonry characteristic

With the marks of the solution

When the strength of the solution, MPa

25-200

ten

four

0.2

null

From large blocks made of heavy and coarse-porous concrete on heavy aggregates and heavy natural stone (180kN / m3)

From stones made of heavy natural stones, heavy concrete and buta

From large blocks made of concrete on porous aggregates and porous porous concrete on light aggregates of dense silicate concrete and from light natural stone

From large blocks made of cellular concrete type

BUT………………………………….

B ………………………………… ..

From stones from cellular concrete of a look

BUT………………………………….

B ………………………………… ..

Of ceramic stones

From ceramic brick of plastic extruded full-bodied and hollow, from hollow silicate stones, from stones made of concrete on porous aggregates and porous, from light natural stones

Made of brick silicate corpulent and hollow

From a ceramic brick of semi-dry pressing of corpulent and hollow

1500

1000

750

500

750

500

1200

1000

750

500

1000

100

750

500

350

1000

750

500

750

500

350

200

750

500

350

750

500

350

200

500

350

500

350

500

350

200

350

200

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Table 4. Calculated resistances R to compression of hollow concrete stone masonry at a height of a series of masonry 200-300mm

Brand of stone

Design resistance R, MPa

With a brand of solution

When the strength of the solution

100

ten

four

0.2

null

100

2.0

1.6

1.2

1.8

1.5

1.15

1.0

1.7

1.4

1.1

0.9

0.7

1.6

1,3

1.0

0.8

0.65

1.4

1.1

0.9

0.7

0.55

1,3

1.0

0.8

0.6

0.5

1.1

0.9

0.7

0.55

0.45

0.9

0.7

0.5

0.4

0.3

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Table 5. The coefficients of buckling φ for different values of the elastic characteristics of the masonry a

Flexibility

Elastic masonry characteristics

a h

λ i

1500

1000

750

500

350

200

100

four

five

eight

ten

eleven

sixteen

thirty

104

111

118

125

132

139

146

160

173

187

one

0.99

0.98

0.96

0.95

0.93

0.92

0.90

0.88

0.86

0.85

0.83

0.81

0.79

0.77

0.73

0.69

0.65

0.61

0.57

0.53

0.49

0.44

0.40

0.36

0.33

0.29

0.21

0.17

0.13

one

0.98

0.96

0.94

0.92

0.90

0.88

0.86

0.84

0.81

0.79

0.77

0.74

0.72

0.70

0.65

0.61

0.56

0.52

0.49

0.45

0.42

0.38

0.35

0.31

0.27

0.25

0.18

0.15

0.12

one

0.97

0.95

0.93

0.9

0.87

0.84

0.81

0.79

0.76

0.73

0.7

0.68

0.65

0.63

0.58

0.53

0.49

0.45

0.42

0.39

0.36

0.32

0.29

0.26

0.23

0.21

0.16

0.13

0.1

0.98

0.94

0.91

0.88

0.85

0.82

0.79

0.75

0.72

0.69

0.66

0.63

0.59

0.56

0.53

0.48

0.43

0.39

0.36

0.34

0.32

0.29

0.26

0.24

0.21

0.19

0.17

0.13

0.1

0.08

0.94

0.91

0.88

0.84

0.8

0.76

0.72

0.68

0.64

0.50

0.57

0.55

0.50

0.47

0.45

0.40

0.35

0.32

0.29

0.27

0.25

0.23

0.21

0.19

0.17

0.16

0.14

0.1

0.08

0.06

0.9

0.86

0.81

0.76

0.7

0.65

0.6

0.56

0.51

0.47

0.45

0.40

0.37

0.35

0.32

0.28

0.24

0.22

0.20

0.18

0.17

0.16

0.14

0.13

0.12

0.11

0.09

0.07

0.05

0.04

0.82

0.75

0.68

0.81

0.54

0.48

0.43

0.38

0.34

0.31

0.28

0.25

0.23

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Notes: 1. The coefficient φ at intermediate values of flexibilities is determined by interpolation.

2. The coefficients of φ for ratios λh exceeding the limiting ones should be taken when determining φс in the case of a calculation for an eccentric compression with a large eccentricity.

3. For each masonry with mesh reinforcement, the values of the elastic characteristics determined by formula 6 can be less than 200.

Table 6. The coefficient η for masonry of various stone materials

λ h

λ l

Masonry coefficient η

From ceramic bricks, from stones and large blocks, from heavy concrete, from natural stones of all kinds

From silicate bricks, from stones and large blocks, from light and cellular concrete

With a percentage of longitudinal reinforcement

0.1 or less

0.3 and more

0.1 or less

0.3 and more

ten

sixteen

thirty

104

111

118

125

132

139

0.04

0.08

0.12

0.15

0.20

0.24

0.27

0.31

0.34

0.38

0.42

0.46

0.49

0.53

0.57

0.03

0.07

0.09

0.13

0.16

0.20

0.23

0.26

0.29

0.32

0.35

0.38

0.42

0.45

0.48

0.05

0.09

0.14

0.19

0.24

0.29

0.33

0.38

0.42

0.47

0.52

0.57

0.61

0.66

0.71

0.03

0.08

0.11

0.15

0.19

0.22

0.26

0.30

0.33

0.37

0.41

0.44

0.48

0.52

0.56

Note. For unreinforced masonry, the values of the coefficient η are accepted as for masonry with a reinforcement of 0.1% or less. When the percentage of reinforcement is more than 0.1% and less than 0.3%, the coefficients η are determined by interpolation.

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Table 7. The coefficient of buckling φ with a = 1000

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λhnp

λ i np

Buckling coefficient φ

λhnp

λ i np

Buckling coefficient φ

four

five

eight

ten

eleven

14.0

17.5

21.0

24.5

28.0

31.5

35.0

38.5

42.0

45.5

49.0

52.5

1.00

0.98

0.96

0.94

0.92

0.90

0.88

0.86

0.84

0.81

0.79

0.77

sixteen

thirty

56.0

63.0

70.0

76.0

83.0

90.0

97.0

104.0

111

118

125

132

139

0.74

0.70

0.65

0.61

0.66

0.52

0.49

0.45

0.42

0.38

0.35

0.31

0.27

Table 8. calculated height of walls and pillars

Structural scheme of the building

Type of construction and method of support

Estimated height

Tough

Articulated bearing

Partial clamping on supports

Bearing on the wall of precast concrete floor

Relying on the wall of the monolithic overlap on four sides

0,8N

0.9N

0,8N

Elastic

Multi-span building

Single span building

1.25H

1.5N

Free-standing construction

2.0H

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Note. The value of H with reinforced concrete precast or monolithic ceilings embedded in masonry, is equal to the height of the floor minus the thickness of the reinforced concrete flooring slab or floor panel. In other cases, the value of H is equal to the height of the floor.

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Table 9. The coefficient ω

Type of masonry

Ω value for sections

Arbitrary shape

Rectangular section

For all types of masonry, except those specified in paragraph 2

From stones and large blocks made of cellular and large-pore concrete, from natural stones (including rubble), from ceramic stones with large voids

1+ e 0/2 y≤1.45

one

1+ e 0 / h≤1.45

one

Note. If 2y <h, then when determining the coefficient ω take the value of h instead of 2y.

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STONE AND ARM-CAMERA KOHCTPUKTII. MATERIALS FOR STONE LAYING

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