Cn dynamic loads. Regulations. Machine foundations with dynamic

Below are examples of calculations of massive foundations for periodic (harmonic) and shock loads and an example of calculation of a frame foundation for harmonic loads. Examples of machine foundation calculations can be found in the Design Guide for Machine Foundations with Dynamic Loads.

Example 9.1. Calculate the foundation of the sawmill frame. The calculation of the foundations of sawmill frames is carried out as for machines with crank mechanisms according to the chapter SNiP "Foundations of machines with dynamic loads". The purpose of the calculation is to determine the dimensions of the foundation that meet the requirements of efficiency and provide an acceptable level of fluctuations.

Initial data: car brand RD 76/6; machine weight 15 tons; weight of the drive motor 2 t; drive motor power 90 kW; motor speed 720 min -1 ; main shaft speed n r= 320 min -1 . The calculated dynamic loads, the coordinates of their application points, the coordinates of the center of gravity of the machine, the dimensions of the upper part of the foundation, the diameter, design and binding of anchor bolts and other initial data for design are specified in the construction assignment of the machine manufacturer for the foundation. The scheme of loads acting on the foundation is shown in fig. 9.1. Permissible amplitudes of horizontal and vertical oscillations of the foundation for the 1st harmonic should be no more than 0.19 mm.

Solution. The design of the foundation of the sawmill is taken as massive from monolithic reinforced concrete. The foundation consists of a lower rectangular slab 6 × 7.5 m in size and 2 m high, taken from the conditions for the location of the drive motor, symmetry requirements and the optimal weight of the foundation, and the upper sloping part, adopted according to technological conditions. The soil filling mark is at the level of the top of the rectangular slab. The foundation material is M200 grade concrete, the reinforcement is hot-rolled, round and periodic profile, respectively, classes A-I and A-II.

The diagram of the masses of the elementary volumes of the foundation and the machine with their binding to the axes of the foundation passing through the center of gravity of the base of the foundation is shown in Fig. 9.1. Mass of sawmill m 1 = 15 t; mass of the beveled part of the foundation m 2 = 22.25 t; mass of the rectangular part of the foundation m 3 = 216 t; weight of the electric motor with a foot m 4 \u003d 2 + 18 \u003d 20 tons.

Total weight of foundation

m f\u003d 22.25 + 216 + 18 \u003d 256.25 tons.

Weight of sawmill and drive motor

m m\u003d 15 + 2 \u003d 17 tons.

Weight of the entire installation

m = m f + m m\u003d 256.25 + 17 \u003d 273.25 tons.

We find the coordinates of the center of gravity of the installation along the axis Z. The static mass moments of the installation elements relative to the axis passing through the base of the foundation will be:

S 1 = 15 5.95 = 89.25 t m; S 2 = 22.25 2.65 = 58.96 t m;

S 3 = 216 1 = 216 t m; S 4 = 20 2.5 = 50 t m;

Distance from the center of gravity of the installation to the base of the foundation

Rice. 9.1.

Finding axis coordinates X. Distance to the center of gravity of the installation along the axis X"

The coordinate of the center of gravity of the installation along the axis Y not determined, since the eccentricity to the axis Y very small (<< 3 % стороны фундамента), а расчет фундамента па колебания должен производиться только в направлении оси X(in the direction of action of dynamic forces).

Sands of medium size lie at the base of the foundation, medium density low-moisture with design resistance R= 350 kPa and modulus of deformation E= 3 10 4 kPa. We check condition (9.1) for γ c 0 = 1 and γ c 1 = 1. Average pressure p = Q/A, where Q = mg, then

kPa< 1·1·350 = 350 кПа.

Calculation of the strength of a massive reinforced concrete foundation is not required. Reinforcement of the foundation is carried out constructively.

The calculation of vibrations of the sawmill foundation is carried out in the following order.

We determine the elastic characteristics of the sandy soil of the base using formulas (9.6) and (9.7):

kN / m 3;

Cφ \u003d 2 44 140 \u003d 88 280 kN / m 3;

C x\u003d 0.7 44 140 \u003d 30,900 kN / m 3.

The stiffness coefficients for the natural foundation are found by formulas (9.8), (9.9) in (9.10), where Iφ \u003d 6 7.5 3 / 12 \u003d 210.94 m 4

kz= 44 140 6 7.5 = 1 986 400 kN/m;

k x= 30,900 6 7.5 = 1,390,000 kN/m;

kφ \u003d 88,280 210.94 \u003d 18,623,000 kN / m.

The values of the relative damping coefficients are determined by formulas (9.13) and (9.15):

; .

The calculated dynamic loads (for the first harmonic of disturbing forces and moments) are determined as follows:

M = F v e + F h e 1 ,

then at F v= 208 kN, F h= 39 kN, e= 0.173 - 0.08 = 0.093 m and e 1 \u003d 5.95 - 1.516 \u003d 4.434 m

M= 208 0.093 + 39 4.434 = 19.4 + 173 = 192.4 kN m.

The amplitudes of the horizontal-rotational and vertical oscillations of the foundation are determined by the formulas:

;

To calculate the amplitudes using these formulas, it is necessary to determine the additional parameters included in them:

here the value θ = 1614.4 t m 2 is obtained by breaking down the foundation and the machine into elementary bodies, calculating their own moments of inertia for them and adding portable moments of inertia equal to the product of the masses of elementary bodies by the squares of distances from their own centers of gravity to the common center of gravity installations;

;

BUILDING REGULATIONS

FOUNDATIONS OF MACHINES WITH DYNAMIC

SNiP 2.02.05-87

USSR STATE CONSTRUCTION COMMITTEE

MOSCOW 1988

DEVELOPED VNIIOSP them. Gersevanova of the State Construction Committee of the USSR (Doctor of Engineering Sciences, Prof. V.A. Ilyichev - leader of the topic, Doctor of Engineering Sciences, Professor D.D. Barkan, Candidates of Engineering Sciences O.Ya. Shakhter, M.N. Golubtsova), Leningrad Promstroyproekt of the State Construction Committee of the USSR (candidates of technical sciences V.M. Pyatetsky, B.K. Aleksandrov, S.K. Shaevich), VNIIG im. B.E. Vedeneeva of the Ministry of Energy of the USSR (Doctors of Technical Sciences, Professors O.A. Savinov, I.S. Sheinin, Candidate of Technical Sciences G.G. Construction Institute of the Ministry of Higher Education of the Ukrainian SSR (candidates of technical sciences N.S. Shvarts, V.L. Sedin), Kharkov Promstroyniiproekt of the State Construction Committee of the USSR (candidate of technical sciences I.M. Balkarei) with the participation of Donetsk Promstroyproekt, NIIZhB, TsNIISK im. Kucherenko and the Central Research Institute of Industrial Buildings of the Gosstroy of the USSR, ENIMS of the USSR Minstankoprom, Gipromez of the USSR Minchermet.

INTRODUCED VNIIOPS them. Gersevanov Gosstroy of the USSR.

PREPARED FOR APPROVAL by the Department of Standardization and Technical Norms in Construction of the USSR State Construction Committee (O.N. Silnitskaya).

With the introduction of SNiP 2.02.05-87 "Foundations of machines with dynamic loads" from July 1, 1988, the chapter of SNiP II-19-79 "Foundations of machines with dynamic loads" becomes invalid.

When using a regulatory document, approved changes to building codes and state standards should be taken into account, published in the journal "bulletin of construction equipment", "Collection of changes to building codes and regulations" of the USSR State Construction Committee and the information index "State Standards of the USSR" of the State Standard of the USSR.

State

building committee of the USSR

Building regulations

SNiP 2.02.05-87

(Gosstroy of the USSR)

Machine foundations with dynamic loads

Instead of a head

SNiP II-19-79

These standards apply to the design of foundations for machines with dynamic loads, including foundations for: machines with rotating parts, machines with crank mechanisms, forging hammers, molding machines for foundry production, molding machines for the production of precast concrete, punching equipment for slaughter sites, crushing , rolling, pressing equipment, mill installations, machine tools and rotary kilns.

Foundations of machines with dynamic loads, designed for construction in areas with difficult engineering and geological conditions, in seismic areas, in undermined territories, at enterprises with systematic exposure to elevated (more than 50 0 C) process temperatures, aggressive environments and in others special conditions, should be designed taking into account the requirements of the relevant regulatory documents.

1. GENERAL PROVISIONS

INITIAL DATA

FOR FOUNDATION DESIGN

1.1. The composition of the initial data for the design of foundations for machines with dynamic loads should include:

technical characteristics of the machine (name, type, number of revolutions per minute, power, total mass and mass of moving parts, kinematic diagram of equipment with binding of moving masses, speed of impacting parts, etc.);

data on the values, places of application and directions of action of static loads, as well as on amplitudes, frequencies, phases, the law of change in time, places of application and directions of action of dynamic loads in normal operation, as well as in emergency modes, including loads acting on foundation bolts: dimensions of load transfer areas; information on the presence of factory vibration isolation for machines, indicating the dynamic loads transferred to the foundations, taking into account this vibration isolation;

data on the limiting values of deformations of foundations and their bases (settlement, roll, deflection of the foundation and its elements, vibration amplitude, etc.), if such restrictions are caused by the conditions of the production technology, the operation of the machine or nearby high-precision and vibration-sensitive equipment; requirements for limiting mutual deformations of individual parts of the machine;

data on the conditions for placing a machine (equipment) on foundations: separate foundations for each machine (unit) or their group installation on a common foundation; data on the characteristics of the base plates (frames) of the aggregated equipment, data on the type of their connection with the foundation;

drawings of the dimensions of the foundation within the location of the machine, its fastening elements, as well as auxiliary equipment and communications, indicating the location and dimensions of recesses, channels and holes, dimensions of the grout, etc., drawings of the location of foundation bolts, indicating their type and diameter, embedded parts, flanging etc.;

Data on the binding of the designed foundation to the structures of the building (structure), in particular, to its foundations, data on the features of the building (structure), including the type and location of the equipment and communications available in it;

data on the engineering and geological conditions of the construction site and the physical and mechanical properties of the foundation soils to the depth of the compressible thickness, determined in accordance with the requirements of SNiP 2.02.01-83; data on the characteristics of vibrocreep of soils in cases of limited foundation deformations; data on the stiffness coefficients of foundation soils and the bearing capacity of piles under static and dynamic loads;

special requirements for the protection of the foundation and its pits from groundwater, exposure to aggressive environments and industrial effluents, temperature effects;

data on the use of machines over time for foundations built on permafrost.

In addition to the data listed above, the relevant sections provide additional initial data for design, arising from the specifics of each type of machine.

GENERAL REQUIREMENTS FOR THE DESIGN OF FOUNDATIONS

1.2. The foundations of machines with dynamic loads must meet the requirements for calculating strength and suitability for normal operation, and for foundations with workplaces located on them, also the requirements of labor safety standards in terms of permissible vibration levels.

Foundation fluctuations should not indicate a harmful effect on technological processes, equipment and instruments located on the foundation or outside it, as well as on those located near the structure of buildings and structures.

When designing the foundations of machines with dynamic loads, the requirements of SNiP 2.02.01-83, SNiP 2.02.03-85, SNiP 2.03.01-84, SNiP II-23-81, etc.

1.3. The foundations of machines with dynamic loads can be concrete or reinforced concrete monolithic, precast-monolithic and prefabricated, and with appropriate justification - metal.

Monolithic foundations should be designed for all types of machines with dynamic loads, and precast-monolithic and prefabricated ones, as a rule, for batch machines (with rotating parts, with crank mechanisms, etc.).

1.4. The concrete compressive strength class for monolithic and precast-monolithic foundations must be at least B12.5, and for prefabricated foundations - at least B15. For non-reinforced foundations of machine tools, it is allowed to use concrete of class B7.5. In the case of simultaneous exposure to the foundation of a dynamic load and elevated process temperatures, the concrete class must be at least B15.

1.5. The foundations of machines can be designed separately for each machine (unit) or common for several machines (aggregates).

The foundations of machines, as a rule, must be separated by a through seam from the adjacent foundations of the building, structure and equipment, as well as from the floor.

Note. The connection of the foundations of machines with the foundations of the building or the support of the building structures on them is allowed in individual cases specified in the individual relevant sections.

1.6. In order to reduce vibrations of the foundations of machines with dynamic loads, it is recommended to provide for their vibration isolation with appropriate justification.

1.7. The construction of foundations for machines with dynamic loads, with the exception of foundations for turbine sets with a capacity of 25 thousand kW or more, is allowed on bulk soils, if such soils do not contain organic impurities that cause uneven soil settlements during compression. In this case, the base of bulk soils must be compacted (by heavy rammers, vibration or other methods) in accordance with the requirements of SNiP 2.02.01-83.

Note. The foundations of machines of non-impulsive (non-impact) action with engines with a power of less than 500 kW with an average pressure under the base of the foundation from design static loads 1 of less than 70 kPa (0.7 kgf / cm 2) may be erected on bulk soils without artificial compaction, if the age of the embankment is made of sandy soils for at least two years and from silty clay soils for at least five years.

1.8. When designing machine foundations on a natural foundation, one should strive to combine on the same vertical the center of gravity of the area of the foundation sole and the lines of action of the resultant static loads from the weight of the machine, the foundation and the soil on the edges and ledges of the foundation, and for pile foundations - the center of gravity of the pile plan and lines of action resultant static loads from the weight of the machine and grillage. In this case, the eccentricity, as a rule, should not exceed (except as specified in remote sections) for soils with design resistance R0 150 kPa (1.5 kgf / cm 2) 3%, and for soils with design resistance R0> 150 kPa (1.5 kgf / cm 2), as well as pile foundations from hanging piles - 5% of the size of the side of the base of the foundation, in the direction of which the center of gravity is shifted. Meaning R0 should be determined according to the tabular data of SNiP 2.02.01-83; for foundations of turbine sets, the eccentricity should not exceed 3% of the specified size, regardless of the value R0. For foundations made of rocky soils, as well as pile foundations from pile-racks, the eccentricity value is not standardized.

1.9. The foundations of machines with dynamic loads should be designed:

massive in the form of a block or slab with the necessary pits, wells and holes for placing parts of the machine, auxiliary equipment, communications, etc.;

wall-mounted, consisting of a lower foundation slab (or grillage), a wall system and an upper slab (or frame) on which the equipment is located;

frame, which is a spatial structure, consisting, as a rule, of an upper slab or a system of beams resting through a series of racks on the lower foundation slab;

lightweight of various constructive types, including non-grilled pile.

1.10. Equipment with rotating parts, crank mechanisms and machine equipment aggregated on reinforced concrete base plates may be installed without foundations on the underlying floor layer industrial buildings when substantiated by calculation, as well as in the cases specified in the relevant sections.

1.11. The sole of the foundations of machines, as a rule, should be provided rectangular shape in plan and placed on the same mark.

The height of the foundations of machines should be set to the minimum of the conditions for placing technological equipment, excavations and shafts, as well as the depth of embedding foundation bolts.

1.12. When designing frame foundations, it is recommended:

observe the symmetry of the foundation both according to the general geometric scheme and the shape of the elements;

to arrange the crossbars of the transverse frames symmetrically with respect to the axes of the uprights;

avoid transferring loads to crossbars and beams with eccentricity;

design the top of the foundations without ledges in height;

assign departures of all consoles of the minimum possible dimensions, and the height of the support section of the console, in the absence of appropriate calculations, should be taken at least 0.75 of its departure.

1.13. The height of the lower foundation slab in wall and frame foundations should be taken according to the calculation, but not less than 0.4 m and not less than the thickness of the wall or larger pillars.

The upper reinforced concrete slab (frame) of the wall foundation must be rigidly connected to the walls. The lower surface of the plate is recommended to be done at one mark.

Walls should be placed, as a rule, along the action of horizontal dynamic loads.

1.14. Types of foundation bolts, methods of their installation, as well as material and setting parameters should be assigned in accordance with the requirements of SNiP 2.09.03-85.

For shock loading, as well as for dynamic loads requiring the installation of bolts with a diameter of at least 42 mm, removable foundation bolts should be used.

The distance from the lower ends of the bolts to the bottom of the foundation must be at least 100 mm.

1.15. Structural reinforcement of massive foundations provides for general reinforcement along the sole and local reinforcement under the machine beds and in places of a sharp change in the dimensions of the foundation section.

When reinforcing the soles of foundations, the diameters of the longitudinal and transverse rods should be taken at least 10 mm with a side of the sole less than 3 m and not less than 12 mm with a larger size with a rod spacing of 200 mm.

In case of local reinforcement under the beds of non-impact machines, the diameter of the rods should be taken depending on the diameter of the bolts that fasten the equipment to the foundations, according to Table. 1. In this case, the size of the meshes should exceed the size of the machine bed in terms of, as a rule, by 300 - 600 mm, depending on the diameter of the reinforcement, equal to 10 - 20 mm, respectively. The recommended rod spacing is 200 mm.

Local reinforcement under the beds of machines with impact loads should be made in accordance with the instructions of the relevant sections.

To reinforce sections of foundations that perceive shock loads, knitted reinforcement should, as a rule, be used. In this case, the protective layer of concrete should be taken at least 30 mm.

Equipment Bolt Diameter , mm
Rod diameter , mm

Note. In massive foundations of non-impact machines with a volume of 20 m 3 or less, general reinforcement along the sole may not be provided.

1.16. Reinforcement of elements of wall and frame foundations is carried out according to the calculation in accordance with the requirements of SNiP 2.03.01-84, taking into account the following additional instructions ;

beam reinforcement , crossbars and racks must have closed clamps or rods , welded to the longitudinal rods along the perimeter of the cross section of the structure ;

racks should be reinforced with symmetrical longitudinal reinforcement with a step of no more than 300 mm ;

on the side faces of beams and crossbars, at least every 300 mm along the height of the section, intermediate rods with a diameter of at least 12 mm should be installed ;

for structural reinforcement of the walls of the wall foundation, the diameter of the vertical rods must be at least 12 mm , and horizontal - at least 10 mm. The step of the rods in both directions should be taken equal to 200 mm.

1.17. Thermal shrinkage joints in foundations should be , as a rule , foresee at distances :

for monolithic concrete foundations 20 m ;

for reinforced concrete monolithic foundations 40 m , precast-monolithic 50m.

These distances may be increased with appropriate justification. In this case, the seams should be positioned in such a way so that on separate sections of the foundation separated by seams , place equipment , not rigidly connected to each other.

To reduce temperature deformations, it is allowed to arrange temporary temperature-shrinkage seams.

When limiting the deflection of the foundation according to technological requirements, instead of temperature-shrinkage joints, measures should be taken to control the temperature regime when laying concrete. In this case, the device of temporary temperature-shrinkage joints is not allowed.

1.18. For foundations or their individual sections exposed to aggressive environments , measures should be taken to protect them in accordance with the requirements of SNiP 2.03.11-85.

GENERAL INSTRUCTIONS FOR THE CALCULATION OF GROUNDS

AND FOUNDATIONS

1.19. Calculation of the foundations of machines and their bases includes :

determination of oscillation amplitudes a foundations or their individual elements ;

checking the average static pressure under the base of the foundation on a natural base R or bearing capacity of piles ;

calculation of the strength of foundation structural elements.

If there are technological requirements in the building for the design limiting movements and deformations of the foundation , their static calculation should be performed from the condition of joint deformation of the base and foundation.

table 2

	Maximum permissible oscillation amplitude a u , mm
With rotating parts at speed , rpm :	Horizontal	vertical

from 500 to 750
from 750 to 1000
from 1000 to 1500

With crank mechanisms at a speed of rotation , rpm :	For the first harmonic	For the second harmonic

from 200 to 400
from 400 to 600

Crushers cone and jaw
Hammer crushers	As for machines with rotating parts
Blacksmith hammers	1, 2 (0, 8*)
	0, 25
Forming machines	0, 5 or in accordance with GOST 12.1.012-78 (when located on the foundations of workplaces)
mills	0, 1**

* When building foundations on all water-saturated sands , as well as on fine and silty, low-moisture and wet sands.

** Root-mean-square value of oscillation amplitude.

Notes : 1. For intermediate speeds, the maximum allowable amplitude is determined by interpolation.

2. For machines with a rotation speed of 200 rpm or less, with a foundation height of more than 5 m, the maximum allowable amplitude increases by 20%.

1.20. The amplitudes of forced and free vibrations of the foundation or its individual elements should be determined for various types of machines in accordance with the instructions in the relevant sections. The oscillation amplitudes are determined separately in directions and corresponding oscillation frequencies.

The vibration amplitudes of the foundation must satisfy the condition

where a- the largest amplitude of foundation oscillations determined by calculation ;

au- maximum allowable amplitude of vibrations of the foundation, set by the design assignment , and in its absence in the task taken according to the table. 2.

When calculating vibrations of machine foundations, it is allowed :

consider the base as elastic-viscous linearly deformable , whose properties are determined by the coefficients of elastic uniform and non-uniform compression , elastic uniform and non-uniform shear and coefficients , characterizing the damping ;

do not take into account the eccentricity in the mass distribution of the foundation , if it does not exceed the values specified in clause 1.8 ;

with elastic uneven compression (rotation of the base of the foundation relative to the horizontal axis passing through the center of gravity of the base of the foundation perpendicular to the plane of vibrations) it is allowed to take that the plane of oscillation is parallel to the line of action of the disturbing force or the plane of action of the disturbing moment.

When several disturbing forces act on the foundation of the machine at the same time and there is no data on their phase relationship, options for in-phase and anti-phase action of forces are considered , causing the most unfavorable modes of vibration.

1.21. Average static pressure under the base of the foundation on a natural base R for all types of machines listed in Table. 3 , must satisfy the condition

R £ g with 0 g with 1 R, (2)

where R- average static pressure under the base of the foundation;

g with 0 - coefficient of working conditions, taken according to table. 3;

g with 1 - coefficient of working conditions of foundation soils, taken for fine and silty water-saturated sands and silty-clayey soils of fluid consistency equal to 0.7 (when designing foundations with a mass of falling parts of more than 10 tons, the value of the coefficient g with 1 \u003d 0.7 is also accepted for low-moisture and wet fine and silty sands and water-saturated sands of medium and large sizes); for all other types and conditions of soils g with 1 =1;

R - design resistance base soil, determined in accordance with the requirements of SNiP 2.02.01-83.

Table 3

	Working conditions coefficient g with 0
With crank mechanisms, presses, machine tools, rotary kilns, rolling equipment
With rotating parts, crushers, mill plants
Forging hammers, molding machines, equipment for fighting sites, for which the foundations are made in the form of a box

1.22. It is allowed to calculate the strength of structural elements of foundations of various types of machines for the static action of the calculated dynamic loads determined by formula (3). Calculation of massive foundations for strength, with the exception of weakened sections, cantilever sections, etc., as a rule, is not performed.

1.23. When determining the calculated static loads, which include the weight of the foundation, the weight of the soil on the edges of the foundation, the weight of the machine and the weight of auxiliary equipment, the load safety factor g f taken in accordance with the requirements of SNiP 2.01.07-85 when calculating the strength and equal to 1 when checking the average static pressure under the base of the foundation.

Estimated dynamic loads F d from the dynamic impact of moving parts of the machine or load, representing any special type of force (for example, the moment of short circuit, breakage of the hammer of the mill, etc.), are determined by:

when calculating oscillations, the product of the value of the standard dynamic load F n, corresponding to the normal operating mode of the machine and taken according to the instructions of the relevant sections or according to the design assignment, and the load safety factor g f =1;

when calculating the strength of foundation structural elements according to the formula

F d=g f h F n, (3)

where g f and h - coefficients, respectively, of reliability for load and dynamism, taken according to table. four;

F n - normative value dynamic load, corresponding to the normal operating mode of the machine or a special force effect and accepted according to the relevant sections or according to the design assignment.

Table 4

	Reliability factor according to	Dynamic factor h for loads
	load g f	vertical	horizontal
With rotating parts:
a) loads created by the moving parts of the machine, at a speed of rotation, rpm:

from 500 to 1500


b) loads from the moment of short circuit
With crank mechanisms at rotational speed, rpm:


Jaw crushers, cone crushers
Hammer crushers
mills

Rental equipment
Rotary kilns

*For intermediate speeds, the dynamic factor values are determined by interpolation.

**For the extreme supports of the foundation to a horizontal load acting across the axis of the furnace (if the number of supports is more than two).

Notes: 1. For turbomachines with a power of more than 25 thousand kW, the value of the coefficient h should be halved.

2. for machines with rotating parts, which also have reciprocating masses, the load safety factor for dynamic loads created by these masses should be taken g f =1,3.

3. Coefficient values h refer to reinforced concrete foundations. For steel foundations, dynamic analysis should be performed.

4. Table values h take into account the alternating effect of loads.

1.24. When designing foundations for machines with dynamic loads for construction in seismic areas, the calculation of the strength of elements of massive foundations should be carried out without taking into account seismic effects.

When calculating frame, wall and lightweight foundations for seismic effects, a special combination of loads should include design dynamic loads created by machines in normal operating mode, with a load safety factor g f =1.

1.25. The main elastic characteristic of the natural foundations of machine foundations is the coefficient of elastic uniform compression, FROMz, kN / m (tf / m 3), should be determined, as a rule, from the test results.

In the absence of experimental data, the value FROMz for foundations with sole area BUT not more than 200 m is allowed to be determined by the formula

(4)

where b 0 - coefficient, m -1, taken equal to 1 for sandy soils, 1.2 for sandy loams and loams, 1.5 for clays and coarse soils;

E- soil deformation modulus under the base of the foundation, kPa (tf / m 2), determined in accordance with the requirements of SNiP 2.02.01-83;

BUT- area of the base of the foundation, m 2.

For foundations with sole area BUT, exceeding 200 m 2, the value of the coefficient FROMz taken as for foundations with sole area BUT\u003d 200m 2.

1.26. Coefficients of elastic non-uniform compression FROM j kN / m (tf / m 3), elastic uniform shear From h kN / m (tf / m 3), and elastic uneven shear FROM y kN / m (tf / m 3), are taken equal to:

1.27. Stiffness coefficients for natural bases Kz,K j ,K x,K y are determined by the formulas:

under elastic uniform compression - Kz, kN/m (tf/m),

with elastic non-uniform compression (rotation of the base of the foundation relative to the horizontal axis passing through the center of gravity of the base of the foundation perpendicular to the plane of oscillation) - K j , kN m (ts m),

with elastic uniform shear - K x, kN/m (tf/m),

with elastic non-uniform shear (rotation of the base of the foundation relative to the vertical axis passing through the center of gravity of the base of the foundation) - K y , kN m (ts m),

In formulas (9), (11):

I j and I y - respectively, the moment of inertia of the area of the base of the foundation relative to the horizontal axis perpendicular to the plane of oscillations, and the vertical axis of the foundation, passing through the center of gravity of the sole, m 4

1.28. The damping properties of the base must be taken into account by the relative damping x (share of critical damping of oscillations), determined, as a rule, from test results.

In the absence of experimental data, relative damping for vertical oscillations is allowed x z determined by the formulas:

for steady (harmonic) and random oscillations

for unsteady (impulse) oscillations

where R- the same as in paragraph 1.21, kPa (tf / m 2),

E, - the same as in paragraph 1.25.

When calculating foundations, it is allowed to use the damping modulus as a characteristic of damping, FZ, s, determined for harmonic and random oscillations by the formula

For impulse oscillations, the value FZ is doubled.

*Formulas in brackets correspond to the "technical" system of units.

1.29. Relative damping and damping modulus for horizontal and rotational vibrations relative to the horizontal and vertical axes are taken equal to:

1.30. For group installation j machines of the same type on a common foundation values of foundation vibration amplitudes a should be determined when j=2 as the sum of the amplitudes, with j> 2 - according to the formula

where k- coefficient taken for machines of periodic action equal to 1.5, for machines with impulse loads - 0.7, for machines with random dynamic loads - 1;

a i- amplitude of oscillations of the foundation during operation i-th machine;

j- the number of cars.

The calculated values of the amplitudes must satisfy condition (1).

In case of group installation of various types of machines on a common foundation, the foundation vibration amplitude should be determined as the sum of the vibration amplitudes caused by the operation of each of the machines. In this case, in condition (1), the maximum allowable amplitude is taken to be 30% more than the values given in Table. 2 for the machine type and oscillation frequency corresponding to the largest component of the calculated amplitude.

When installing machines with periodic and random loads on separate foundations, the vibration amplitude of each foundation should be determined taking into account the vibrations propagating in the soil during the operation of machines installed on other foundations, in accordance with the instructions of mandatory Appendix 4. In this case, the permissible vibration amplitude of the receiver foundation a u should be taken 30% more than the values of the maximum allowable amplitudes given in Table. 2.

For the foundations of machines with impulse loads installed on separate foundations, the calculation of vibration amplitudes is allowed without taking into account the transmission of vibrations along the ground.

1.31. The calculation of the amplitudes of vertical (horizontal) ground vibrations, respectively, with vertical (horizontal) vibrations of machine foundations should be carried out according to the formula

(19)

where a s- amplitude of vertical (horizontal) ground vibrations on the surface at a point located at a distance r from the axis of the foundation, i.e. source of waves in the ground;

a 0 - amplitude of free or forced vertical (horizontal) oscillations of the foundation, i.e. wave source in the ground at the level of its sole, determined for various types of machines according to the formulas of mandatory applications 1-3, in which h 1 should be replaced with minus h 2 ;

d = r/ r 0 ;

here r- distance from the axis of the foundation-source to a point on the soil surface, for which the oscillation amplitude is determined;

r 0 - reduced radius of the base of the foundation-source,

The frequency of waves propagating in the ground should be taken equal to the vibration frequency of the foundation of the machine.

Note. In order to clarify the amplitudes of oscillations propagating in the ground, it is allowed to predict ground oscillations on the basis of special experimental studies.

1.32. When designing the foundations of buildings and structures that are sensitive to uneven precipitation and perceive dynamic loads transmitted by machines through building construction or soil, the average pressure under the base of the foundation on a natural foundation must satisfy the condition

Condition (20) must be satisfied for the foundations of buildings and structures within the zone where the vibration velocity n s= a w on the ground surface from pulsed sources more than 15 mm/s, from periodic and random sources more than 2 mm/s (here a s- amplitude of ground vibrations, determined by formula (19), w - angular frequency of forced oscillations of the foundation-source for machines with periodic loads or own - for machines with impulse or random loads).

FEATURES OF DESIGNING PILE FOUNDATIONS

1.33. For the foundations of machines with periodic loads, it is possible to use piles of any kind; for the foundations of percussion machines, reinforced concrete piles of a solid section should be used.

The distance between the centers of piles in pile foundations should be taken in accordance with the instructions of SNiP 2.02.03-85, but not more than 10 d(where d- diameter or smaller dimension of the side of the cross section of the piles).

1.34. Calculation of pile foundations of machines with dynamic loads according to the bearing capacity of pile foundation soils should be carried out for the effect of calculated statistical loads in accordance with the requirements of SNiP 2.02.03-85.

In this case, the calculated resistance of the foundation soils on the side surface of the piles and under their lower end should be additionally multiplied by the coefficients of the working conditions of the foundation soil, respectively g cf , f and g cf , R given in Table. 5, and their sum for hanging piles - by the coefficient of working conditions g co , the values of which are given in Table. 3. For pile-racks, the coefficient g co is taken equal to 1.

Table 5

	Coefficients of working conditions of foundation soils
	on the side surface of the pile g cf , f	under the bottom of the pile g cf , R
a) Loose sands of any size and humidity; fine and dusty water-saturated of any density; silty-clayey soils with a fluidity index I L> 0,6
b) Silty sands, fine and medium size of medium density of any humidity, except for those indicated in pos. "a"; silty clay soils with a flow index of 0.25 £ I L £0.6
Other types of soil
Notes: 1. In parentheses are the values of the coefficients for pile foundations with an intermediate cushion. 2. When using piles in subsiding soils, the values of the coefficients g cf , f and g cf , R are accepted as for silty clay soils with a yield index equal to the value at which, in accordance with the instructions of SNiP 2.02.03-85, the calculated soil resistances under the lower end and on the side surface of the pile are determined.

In the case of determining the bearing capacity of piles based on the results of field tests, instead of the coefficients g cf , f and g cf , R the coefficient of working conditions of the foundation soils is introduced g cf , defined as the ratio of the bearing capacity of the pile , by a certain calculation method, taking into account the coefficients g cf , f and g cf , R, to the same bearing capacity without taking into account these coefficients.

In the case of piles resting on soils indicated in pos. "a" tab. 5 , the bearing capacity of piles should be determined based on the results of field tests with long-term dynamic loads. In the absence of such data, with appropriate justification, it is allowed to determine the bearing capacity of piles based on the results of field tests in accordance with the requirements of SNiP 2.02.03-85 with the introduction instead of coefficients g cf , f and g cf , R coefficient g cf =0,25.

1.35. When arranging pile foundations for buildings and structures located near the foundations of machines with dynamic loads , the bearing capacity of piles is determined in accordance with the requirements of SNiP 2.02.03-85, taking into account the additional coefficient of the operating conditions of the foundation soils g cf (or g cf , f and g cf , R), the values of which are determined in accordance with paragraph 1.34. Zone dimensions , for which the specified coefficient is taken into account , should be taken in accordance with the instructions of paragraph 1.32.

1.36. Calculation of vibrations of pile foundations of machines should be carried out according to the same formulas , as for foundations on a natural basis , but when introduced instead of mass values , mass moments of inertia and rigidities m, q j , q j o , q y , TO z , K x , TO j K y their corresponding reduced values m red, q j , red, q j o , red, q y ;

Eb- modulus of elasticity of pile material kPa (tf × /m 2) ;

l- depth of immersion of the pile into the ground , m ;

l about- distance from the base of the grillage to the ground surface , m ; for low grillage l about=0;

A r- cross-sectional area of the pile , m 2 ;

and- perimeter of the cross section of the pile , m ;

The coefficient of elastic uniform compression of the soil at the level of the lower ends of the piles , kN / m 3 (tf / m 3) , determined by formula (4) , in which the area of the base of the foundation BUT taken equal to the area of the largest cross-section of the lower end of the pile , and the value of the coefficient b o for driven piles doubles ;

to* - coefficient , taken equal for piles : 2 - for solid reinforced concrete ; 2, 5 - for hollow reinforced concrete ; 3, 5 - for wooden ;

with p , to - specific elastic soil resistance on the side surface of the pile in k th layer taken according to the table. 6 and 7 ;

s o- coefficient , taken equal to 10000 kN / m 3 (1000 tf / m 3) ;

kl and kl*- soil layer number , measured from the ground surface to the depth , equal respectively l and l* = 0, 2 l;

lk- thickness k-th layer of soil ;

th - hyperbolic tangent.

Note. When the distance between piles decreases from 5 d up to 2 d meaning Toz , red should be halved (for intermediate distances determined by interpolation).

Table 6

Fluidity index of silty clay soils I L	Resistivity with p , kN / m 3 (tf / m 3)
0, 75< I L £1	1, 5× 10 4 -0 , 5× 10 4 (1500-500)
0, 5< I L £ 0 , 75	3× 10 4 -1 , 5× 10 4 (3000-1500)
0, 25< I L £ 0 , 5	4, 5× 10 4 -3 × 10 4 (4500-3000)
0< I L£ 0 , 25	6× 10 4 -4 , 5× 10 4 (6000-4500)
Notes : 1. For intermediate values of I L, the value of c p is determined by interpolation. 2. For subsiding soils, the values of specific elastic resistance c p should be determined as for silty clay soils with flow indices I L corresponding to natural humidity or taking into account possible soaking in accordance with the requirements of SNiP 2.02.03-85.

For horizontal vibrations of pile foundations

9.1. Foundations for machines with dynamic loads.

9.1.1. Machine types.

Batch machines are divided into three subgroups: with uniform rotation (electric motors, motor generators, turbogenerators, rotors, etc.); with uniform rotation and associated reciprocating motion (compressors, pumps, internal combustion engines, sawmills, etc.); with reciprocating motion, ending with continuous blows following one after another (shaking and vibrating-shock machines).

Non-batch machines also divided into three subgroups: with uneven rotation or reciprocating motion (driving electric motors of rolling mills, generators of discontinuous power, etc.); with reciprocating motion, ending with individual blows (forging and stamping hammers, pile drivers, etc.); with pressure causing movement of the processed material and transferring random loads to the foundation (mill installations).

9.1.2. Types of foundations for machines with dynamic loads

1) massive, concrete or reinforced concrete for all types of machines;

2) frame, prefabricated or precast-monolithic, which is a series of transverse frames that rest on the bottom slab or on the grillage and are connected on top of each other by longitudinal beams, or the top slab, which rests on racks embedded in the bottom slab, or on piles columns;

3) wall-mounted in the form of transverse or longitudinal walls, resting on the lower slab or on the grillage and interconnected on top with crossbars or a slab.

Prefabricated-monolithic and prefabricated foundations are allowed to be arranged mainly for intermittent machines, not allowed for machines with impulse shock loads.

9.1.3. Calculation of the foundations of such foundations.

For the first group of limit states, the following is performed:

1) checking the average static pressure under the sole for foundations on a natural foundation or the bearing capacity of the foundation for pile foundations; this check is made for all types of machines without exception

where is the average pressure on the base under the base of the foundation from the calculated static loads (weight of the foundation, soil on its edges, machine and auxiliary equipment with an overload factor n=1); the coefficient of working conditions of the foundation soils, taking into account the nature of the dynamic load and the responsibility of the machine; coefficient of working conditions of foundation soils, taking into account the possibility of long-term deformations under the action of dynamic loads; calculated soil resistance.

where is the bearing capacity of the soils of the base of a single pile; bearing capacity of the pile in static conditions, determined depending on the type of pile and soil conditions; and coefficients of working conditions of the foundation soils, taken depending on the soil conditions;

2) calculation of the strength of individual elements of the foundation structure; the calculation is made for individual elements of frame and wall foundations subjected to dynamic loads (pillars and crossbars of frames, beams, slabs, cantilever ledges), foundations of slab and beam type, as well as individual sections of massive foundations, weakened by holes and recesses (according to SNiP "Concrete and reinforced concrete structures).

Calculation of foundations for the second group of limit states includes:

1) determination of vibration amplitudes of foundations or their individual elements; the calculation is made in accordance with SNiP “Foundations of machines with dynamic loads. Design standards" and is decisive in the design of foundations for machines with dynamic loads

where is the largest amplitude of fluctuations of the upper face of the foundation, calculated for a certain type of foundation for machines; maximum permissible oscillation amplitude, determined according to SNiP 2.02.05-87;

2) determination of settlements and deformations (deflections, heels, etc.) of foundations or their elements; these calculations are performed in some cases for critical structures and in the presence of requirements that limit the movement and deformation of foundations (according to SNiP 2.02.01-83).

9.1.4. Calculation for fluctuations.

When assigning safe distances to objects sensitive to vibrations, the level of vibrations propagating in the ground from the foundations of machines can be approximately estimated by the formula:

where is the amplitude of vertical (horizontal) ground oscillations on the surface at a point located at a distance from the axis of the foundation - the source of waves in the ground; the amplitude of free or forced vertical (horizontal) oscillations of the foundation - the source at the level of its sole; (reduced radius of the base of the foundation - source, m, equal to; area of the base of the foundation - source).

9.1.5. Determination of elastic and damping characteristics of the base for the calculation of foundations.

The main elastic characteristic of the natural foundations of machine foundations - the coefficient of elastic uniform compression, kN / m 3, is determined experimentally. If there are no tests, for foundations with a sole area BUT no more than 200 m 2

where is the coefficient depending on the type of soil; modulus of soil deformation under the base of the foundation; m 2.

Coefficients of elastic non-uniform compression, elastic uniform shear, elastic non-uniform shear:

Stiffness coefficients for natural bases:

with vertical translational oscillations of the foundation (with elastic uniform compression)

with horizontal translational oscillations of the foundation (with elastic uniform shear)

with rotational vibrations about a horizontal axis passing through the base of the foundation (with elastic uneven compression)

with rotational vibrations about the vertical axis passing through the center of gravity of the base of the foundation (with elastic uneven shear)

where is the area of the base of the foundation; moments of inertia of the base of the foundation relative to the horizontal and vertical axes.

These coefficients relate the stresses and moments acting on the base of the foundation, with the corresponding elastic movements caused by them: vertical, horizontal, rotations and relative to the main horizontal and vertical axes of inertia passing through the center of gravity of the base of the foundation

As oscillations propagate in the ground, they are attenuated, which is usually estimated by the relative damping coefficient. Relative damping is the proportion of the critical damping of vibrations. distance from the common center of gravity of the installation to the base of the foundation; vertical and horizontal components of disturbing forces and moment from disturbing forces; angular frequency of rotation of the machine.

Page 4 of 23

GENERAL INSTRUCTIONS FOR THE CALCULATION OF BASES AND FOUNDATIONS

1.19. The calculation of the foundations of machines and their bases includes:

determination of oscillation amplitudes a foundations or their individual elements;

checking the average static pressure under the base of the foundation on a natural base R or bearing capacity of piles;

calculation of the strength of foundation structural elements.

If there are technological requirements in the building for the design that limit the movement and deformation of the foundation, their static calculation should be performed from the condition of joint deformation of the base and foundation.

table 2

Cars	Maximum permissible oscillation amplitude and u, mm
With rotating parts at rotational speed, rpm:	Horizontal	vertical
less than 500	0,2	0,15
from 500 to 750	0,2-0,15	0,15-0,1
from 750 to 1000	0,15-0,1	0,1-0,06
from 1000 to 1500	0,1-0,05	0,06
over 1500	0,05	-
With crank mechanisms at rotational speed, rpm:	For the first harmonic	For the second harmonic
less than 200	0,25	0,15
from 200 to 400	0,25-0,15	0,15-0,1
from 400 to 600	0,15-0,1	0,1-0,05
over 600	0,1	0,05
Crushers cone and jaw	0,3
Hammer crushers	As for machines with rotating parts
Blacksmith hammers	1,2 (0,8*)
Presses	0,25
Forming machines	0.5 or according to GOST 12.1.012-78 (when located on the foundations of workplaces)
mills	0,1**

* When building foundations on all water-saturated sands, as well as on fine and dusty, low-moisture and wet sands.

** Root-mean-square value of oscillation amplitude.

Notes: 1. For intermediate speeds, the maximum allowable amplitude is determined by interpolation.

2. For machines with a rotation speed of 200 rpm or less, with a foundation height of more than 5 m, the maximum allowable amplitude increases by 20%.

The vibration amplitudes of the foundation must satisfy the condition

where a- the largest amplitude of foundation oscillations, determined by calculation;

and u- the maximum permissible amplitude of vibrations of the foundation, established by the design assignment, and in its absence in the assignment, taken according to Table. 2.

When calculating vibrations of machine foundations, it is allowed:

consider the base as elastic-viscous linearly deformable, the properties of which are determined by the coefficients of elastic uniform and non-uniform compression, elastic uniform and non-uniform shear and coefficients characterizing damping;

do not take into account the eccentricity in the mass distribution of the foundation, if it does not exceed the values specified in clause 1.8;

in case of elastic uneven compression (rotation of the base of the foundation relative to the horizontal axis passing through the center of gravity of the base of the foundation perpendicular to the plane of oscillations), it is allowed to assume that the plane of oscillations is parallel to the line of action of the disturbing force or the plane of action of the disturbing moment.

When several disturbing forces act on the foundation of the machine at the same time and there is no data on their phase relationship, variants of in-phase and anti-phase action of forces that cause the most unfavorable vibration modes are considered.

1.21. Average static pressure under the base of the foundation on a natural base R for all types of machines listed in Table. 3 must satisfy the condition

R £ g with 0 g with 1 R, (2)

where R- average static pressure under the base of the foundation;

g with 0 - coefficient of working conditions, taken according to table. 3;

R- design soil resistance of the base, determined in accordance with the requirements of SNiP 2.02.01-83.

Table 3

1.23. When determining the calculated static loads, which include the weight of the foundation, the weight of the soil on the edges of the foundation, the weight of the machine and the weight of auxiliary equipment, the load safety factor g f taken in accordance with the requirements of SNiP 2.01.07-85 when calculating the strength and equal to 1 when checking the average static pressure under the base of the foundation.

when calculating the strength of foundation structural elements according to the formula

F d=g f h F n, (3)

where g f and h- coefficients, respectively, of reliability for load and dynamism, taken according to table. four;

F n- standard value of dynamic load corresponding to the normal operating mode of the machine or a special force effect and taken according to the relevant sections or according to the design assignment.

Table 4

	Reliability factor according to	Dynamic factor h for loads
	load	vertical	horizontal
With rotating parts:
a) loads created by the moving parts of the machine, at a speed of rotation, rpm:
less than 500	4	3	2
from 500 to 1500	4	3-6*	2
1500 2000	4	6-10*	2
St. 2000	4	10	2
b) loads from the moment of short circuit	1	2	-
With crank mechanisms at rotational speed, rpm:
up to 600	2	1	1
St. 600	1	4	2
Jaw crushers, cone crushers	1,3	1,2	1,2
Hammer crushers	4	1	1
mills	1,3	-	1
Presses	1,5	2	2
Rental equipment	1,2	2	2
Rotary kilns	1(2**)	1	1

*For intermediate speeds, the dynamic factor values are determined by interpolation.

**For the extreme supports of the foundation to a horizontal load acting across the axis of the furnace (if the number of supports is more than two).

Notes: 1. For turbomachines with a power of more than 25 thousand kW, the value of the coefficient h should be halved.

2. for machines with rotating parts, which also have reciprocating masses, the load safety factor for dynamic loads created by these masses should be taken g f =1,3.

3. Coefficient values h refer to reinforced concrete foundations. For steel foundations, dynamic analysis should be performed.

4. Table values h take into account the alternating effect of loads.

1.25. The main elastic characteristic of the natural foundations of machine foundations is the coefficient of elastic uniform compression, C z, kN / m (tf / m 3), should be determined, as a rule, from the test results.

In the absence of experimental data, the value C z for foundations with sole area BUT not more than 200 m is allowed to be determined by the formula

(4)

where b 0 - coefficient, m -1, taken equal to 1 for sandy soils, 1.2 for sandy loams and loams, 1.5 for clays and coarse soils;

E- soil deformation modulus under the base of the foundation, kPa (tf / m 2), determined in accordance with the requirements of SNiP 2.02.01-83;

BUT- area of the base of the foundation, m 2.

For foundations with sole area BUT, exceeding 200 m 2, the value of the coefficient C z taken as for foundations with sole area BUT\u003d 200m 2.

1.26. Coefficients of elastic non-uniform compression C j kN / m (tf / m 3), elastic uniform shear From h kN / m (tf / m 3), and elastic uneven shear C y kN / m (tf / m 3), are taken equal to:

1.27. Stiffness coefficients for natural bases Kz, Kj, K x, K y are determined by the formulas:

under elastic uniform compression - Kz, kN/m (tf/m),

with elastic uniform shear - K x, kN/m (tf/m),

with elastic non-uniform shear (rotation of the base of the foundation relative to the vertical axis passing through the center of gravity of the base of the foundation) - K y, kN m (tf m),

In formulas (9), (11):

Ij and I y- respectively, the moment of inertia of the area of the base of the foundation relative to the horizontal axis perpendicular to the plane of oscillations, and the vertical axis of the foundation, passing through the center of gravity of the sole, m 4

1.28. The damping properties of the base must be taken into account by the relative damping x(share of critical damping of oscillations), determined, as a rule, from test results.

In the absence of experimental data, relative damping for vertical oscillations is allowed xz determined by the formulas:

for steady (harmonic) and random oscillations

for unsteady (impulse) oscillations

where R- the same as in paragraph 1.21, kPa (tf / m 2),

E, - the same as in paragraph 1.25.

When calculating foundations, it is allowed to use the damping modulus as a characteristic of damping, F Z, s, determined for harmonic and random oscillations by the formula

For impulse oscillations, the value F Z is doubled.

*Formulas in brackets correspond to the "technical" system of units.

1.29. Relative damping and damping modulus for horizontal and rotational vibrations relative to the horizontal and vertical axes are taken equal to:

where k- coefficient taken for machines of periodic action equal to 1.5, for machines with impulse loads - 0.7, for machines with random dynamic loads - 1;

a i- amplitude of oscillations of the foundation during operation i-th machine;

j- the number of cars.

The calculated values of the amplitudes must satisfy condition (1).

When installing machines with periodic and random loads on separate foundations, the vibration amplitude of each foundation should be determined taking into account the vibrations propagating in the soil during the operation of machines installed on other foundations, in accordance with the instructions of mandatory Appendix 4. In this case, the permissible vibration amplitude of the receiver foundation a u should be taken 30% more than the values of the maximum allowable amplitudes given in Table. 2.

(19)

where a s- amplitude of vertical (horizontal) ground vibrations on the surface at a point located at a distance r from the axis of the foundation, i.e. source of waves in the ground;

d = r / r 0 ;

here r- distance from the axis of the foundation-source to a point on the soil surface, for which the oscillation amplitude is determined;

r 0 - reduced radius of the base of the foundation-source,

The frequency of waves propagating in the ground should be taken equal to the vibration frequency of the foundation of the machine.

Note. In order to clarify the amplitudes of oscillations propagating in the ground, it is allowed to predict ground oscillations on the basis of special experimental studies.

1.32. When designing the foundations of buildings and structures that are sensitive to uneven settlements and perceive dynamic loads transmitted by machines through building structures or soil, the average pressure under the base of the foundation on a natural basis must satisfy the condition

Condition (20) must be satisfied for the foundations of buildings and structures within the zone where the vibration velocity n s= aw on the ground surface from pulsed sources more than 15 mm/s, from periodic and random sources more than 2 mm/s (here a s- amplitude of ground vibrations, determined by formula (19), w- angular frequency of forced oscillations of the foundation-source for machines with periodic loads or own - for machines with impulse or random loads).

DEVELOPED VNIIOSP them. Gersevanova of the State Construction Committee of the USSR (Doctor of Engineering Sciences, Prof. V.A. Ilyichev - Head of the theme, Doctor of Engineering Sciences, Professor D.D. Barkan, Candidates of Engineering Sciences O.Ya. Shekhter, M.N. Golubtsova), Leningrad Promstroyproekt of the State Construction Committee of the USSR (candidates of technical sciences V.M. Pyatetsky, B.K. Aleksandrov, S.K. Lapin; I.I. Fainberg), Fundamentproekt of the USSR Ministry of Installation and Special Construction (candidate of technical sciences V.M. Shaevich), VNIIG im. B.E. Vedeneeva of the Ministry of Energy of the USSR (Doctors of Technical Sciences, Professors O.A. Savinov, I.S. Sheinin, Candidate of Technical Sciences G.G. Construction Institute of the Ministry of Higher Education of the Ukrainian SSR (candidates of technical sciences N.S. Shvets, V.L. Sedin), Kharkov Promstroyniiproject of the USSR State Construction Committee (candidate of technical sciences I.M. Balkarei) with the participation of Donetsk Promstroyniiproekt, NIIZHB, TsNIISK im. Kucherenko and the Central Research Institute of Industrial Buildings of the Gosstroy of the USSR, ENIMS of the USSR Minstankoprom, Gipromez of the USSR Minchermet.

With the entry into force of SNiP 2.02.05-87 "Foundations of machines with dynamic loads" from July 1, 1988, the chapter of SNiP II-19-79 "Foundations of machines with dynamic loads" becomes invalid.

The foundations of machines with dynamic loads intended for construction in areas with difficult engineering and geological conditions, in seismic areas, in undermined territories, at enterprises with systematic exposure to elevated (more than 50 ° C) process temperatures, aggressive environments and in other special conditions, should design in accordance with the requirements of the relevant regulatory documents.

Technical specifications machines (name, type, number of revolutions per minute, power, total mass and mass of moving parts, kinematic diagram of equipment with binding of moving masses, speed of impacting parts, etc.);

Data on the values, places of application and directions of action of static loads, as well as on amplitudes, frequencies, phases, the law of change in time, places of application and directions of action of dynamic loads in normal operation, as well as in emergency modes, including loads acting on foundation bolts; dimensions of the load transfer areas; information on the presence of factory vibration isolation for machines, indicating the dynamic loads transferred to the foundations, taking into account this vibration isolation;

Data on the limiting values of deformations of foundations and their foundations (settlement, roll, deflection of the foundation and its elements, vibration amplitude, etc.), if such limitations are caused by the conditions of the production technology, the operation of the machine or nearby high-precision and vibration-sensitive equipment; requirements for limiting mutual deformations of individual parts of the machine;

Data on the conditions for placing a machine (equipment) on foundations: separate foundations for each machine (unit) or their group installation on a common foundation; data on the characteristics of the base plates (frames) of the aggregated equipment, data on the type of their connection with the foundation;

Drawings of the dimensions of the foundation within the location of the machine, its fastening elements, as well as auxiliary equipment and communications, indicating the location and dimensions of recesses, channels and holes, sizes of grout, etc., drawings of the location of foundation bolts, indicating their type and diameter, embedded parts, flanging etc.;

Data on the engineering and geological conditions of the construction site and the physical and mechanical properties of the foundation soils to the depth of the compressible thickness, determined in accordance with the requirements of SNiP 2.02.01-83; data on the characteristics of vibrocreep of soils in cases of limited foundation deformations; data on the stiffness coefficients of foundation soils and the bearing capacity of piles under static and dynamic loads;

Special requirements for the protection of the foundation and its pits from groundwater, exposure to aggressive environments and industrial effluents, temperature effects;

In addition to the data listed above, the relevant sections provide additional initial data for design, arising from the specifics of each type of machine.

1.3. The foundations of machines with dynamic loads can be concrete or reinforced concrete monolithic, precast-monolithic and prefabricated, and with appropriate justification - metal.

The foundations of machines, as a rule, must be separated by a through seam from the adjacent foundations of the building, structure and equipment, as well as from the floor.

1.6. In order to reduce vibrations of the foundations of machines with dynamic loads, it is recommended to provide for their vibration isolation with appropriate justification.

Note. Foundations of machines of non-impulsive (non-impact) action with engines with a power of less than 500 kW with an average pressure under the base of the foundation from design static loads * less than 70 kPa (0.7)

It is allowed to erect on bulk soils without artificial compaction, if the age of the embankment from sandy soils is at least two years and from silty clay soils is not less than five years.

1.8. When designing machine foundations on a natural foundation, one should strive to combine on the same vertical the center of gravity of the area of the foundation sole and the line of action of the resultant static loads from the weight of the machine, the foundation and the soil on the edges and ledges of the foundation, and for pile foundations - the center of gravity of the pile plan and the line of action resultant static loads from the weight of the machine and grillage. In this case, the eccentricity, as a rule, should not exceed (except as specified in separate sections) for soils with a design resistance of 150 kPa (1.5) 3%, and for soils with a design resistance of >150 kPa (1.5), as well as pile foundations from hanging piles - 5% of the size of the side of the base of the foundation, in the direction of which the center of gravity is shifted. The value should be determined according to the tabular data of SNiP 2.02.01-83; for foundations of turbine sets, the eccentricity should not exceed 3% of the specified size, regardless of the value of . For foundations built of rocky soils, as well as pile foundations from pile-racks, the eccentricity value is not standardized

Cn dynamic loads. Regulations. Machine foundations with dynamic

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