Centrally stretched and centrally compressed elements. General provisions. a - gross section area Gross section

28.03.2020

4.5. The estimated length of the elements should be determined by multiplying their free length by a factor

according to paragraphs 4.21 and 6.25.

4.6. Composite elements on pliable joints, supported by the entire cross section, should be calculated for strength and stability according to formulas (5) and (6), while also being determined as the total areas of all branches. The flexibility of the constituent elements should be determined taking into account the compliance of the joints according to the formula

(11)

		flexibility of the entire element relative to the axis (Fig. 2), calculated from the effective length without compliance;
			flexibility of a separate branch relative to the axis I - I (see Fig. 2), calculated from the estimated length of the branch; with less than seven thicknesses () branches take =0;
			coefficient of reduction of flexibility, determined by the formula

(12)

		width and height cross section element, cm;
			the estimated number of seams in the element, determined by the number of seams over which the mutual shift of the elements is summed up (in Fig. 2, a - 4 seams, in Fig. 2, b - 5 seams);
			estimated length of the element, m;
			the estimated number of cuts of bonds in one seam per 1 m of the element (for several seams with a different number of cuts, the average number of cuts for all seams should be taken);
			the coefficient of compliance of the joints, which should be determined by the formulas of Table 12.

When determining the diameter of nails, no more than 0.1 of the thickness of the connected elements should be taken. If the size of the pinched ends of the nails is less than 4, then the cuts in the seams adjacent to them are not taken into account in the calculation. The value of joints on steel cylindrical dowels should be determined by the thickness of the thinner of the connected elements.

Rice. 2. Components

a - with gaskets; b - without gaskets

Table 12

Connection type	Coefficient at
	central compression	bending compression


2. Steel cylindrical pins:
a) the diameter of the thickness of the connected elements
b) diameter > thickness of connected elements
3. Oak cylindrical dowels
4. Oak lamellar dowels

Note: The diameters of nails and dowels, the thickness of the elements, the width and thickness of the lamellar dowels should be taken in cm.

When determining the diameter of oak cylindrical dowels, no more than 0.25 of the thickness of the thinner of the connected elements should be taken.

Ties in the seams should be spaced evenly along the length of the element. In hinged-supported rectilinear elements, it is allowed to put connections in the middle quarters of the length in half the amount, introducing into the calculation according to formula (12) the value taken for the extreme quarters of the length of the element.

The flexibility of a composite element calculated by formula (11) should be taken no more than the flexibility of individual branches, determined by the formula

(13)

		the sum of the gross moments of inertia of the cross sections of individual branches relative to their own axes parallel to the axis (see Fig. 2);
			gross sectional area of the element;
			Estimated element length.

The flexibility of a composite element relative to the axis passing through the centers of gravity of the sections of all branches (the axis in Fig. 2) should be determined as for a solid element, i.e. without taking into account the compliance of the bonds, if the branches are loaded evenly. In the case of unevenly loaded branches, paragraph 4.7 should be followed.

If the branches of a composite element have a different cross section, then the calculated flexibility of the branch in formula (11) should be taken equal to:

(14)

the definition is given in Fig.2.

4.7. Composite elements on pliable joints, some of the branches of which are not supported at the ends, can be calculated for strength and stability according to formulas (5), (6) subject to the following conditions:

a) the cross-sectional area of \u200b\u200bthe element and should be determined by the cross section of the supported branches;

b) the flexibility of the element relative to the axis (see Fig. 2) is determined by the formula (11); in this case, the moment of inertia is taken taking into account all branches, and the area - only supported ones;

c) when determining the flexibility relative to the axis (see Fig. 2), the moment of inertia should be determined by the formula

moments of inertia of the cross sections of supported and unsupported branches, respectively.

4.8. The calculation for the stability of centrally compressed elements of a section with a variable height should be performed according to the formula

		gross cross-sectional area with maximum dimensions;
		coefficient taking into account the variability of the section height, determined according to Table 1, Appendix 4 (for elements of a constant section);
		buckling coefficient determined according to item 4.3 for flexibility corresponding to the section with maximum dimensions.

Bending elements

4.9. Calculation of bending elements, secured against buckling of the flat form of deformation (see clauses 4.14 and 4.15), for strength under normal stresses should be carried out according to the formula

		calculated bending moment;
		design resistance to bending;
		design modulus of the element's cross section. For solid members for bending components on yielding joints, the calculated modulus of modulus should be taken equal to the net modulus multiplied by the factor ; values for elements composed of identical layers are given in Table 13. When determining the weakening of the sections, located on the section of the element with a length of up to 200 mm, they are taken combined in one section.

Table 13

Coefficient notation	Number of layers per element	The value of the coefficients for the calculation of bending components during spans, m








Note. For intermediate values of the span and the number of layers, the coefficients are determined by interpolation.

4.10. Calculation of bending elements for shearing strength should be performed according to the formula

		design shear force;
		static gross moment of the shifted part of the cross section of the element relative to the neutral axis;
		gross moment of inertia of the cross section of the element relative to the neutral axis;
		calculated width of the section of the element;
		design resistance to shearing in bending.

4.11. The number of cuts , evenly spaced in each seam of a composite element in a section with an unambiguous diagram of transverse forces, must satisfy the condition

(19)

		the calculated bearing capacity of the connection in this seam;
		bending moments in the initial and final sections of the section under consideration.

Note. If there are bonds of different bearing capacity in the seam, but

identical in nature of work (for example, dowels and nails), bearing

their abilities should be summed up.

4.12. The calculation of elements of a solid section for strength in oblique bending should be carried out according to the formula

(20)

	components of the calculated bending moment for the main axes of the section and
	section modulus netto about the main axes of the section and

4.13. Glued curvilinear elements that are bent by a moment that reduces their curvature should be checked for radial tensile stresses according to the formula

(21)

		normal stress in the extreme fiber of the stretched zone;
		normal stress in the intermediate fiber of the section for which the radial tensile stresses are determined;
		the distance between the extreme and considered fibers;
		the radius of curvature of the line passing through the center of gravity of the diagram of normal tensile stresses, enclosed between the extreme and considered fibers;
		calculated wood tensile strength across the fibers, taken according to clause 7 of Table 3.

4.14. Calculation for the stability of the flat form of deformation of bent elements of rectangular section should be carried out according to the formula

		maximum bending moment in the section under consideration
		maximum gross modulus in the area under consideration

The coefficient for bending elements of rectangular cross section, hinged against displacement from the bending plane and fixed against rotation around the longitudinal axis in the reference sections, should be determined by the formula

		the distance between the support sections of the element, and when fixing the compressed edge of the element at intermediate points from displacement from the bending plane - the distance between these points;
		cross section width;
		the maximum height of the cross section on the site;
		coefficient depending on the shape of the curve of bending moments in the section, determined according to tables 2, 3, appendix 4 of these standards.

When calculating bending moments with a height linearly changing along the length and a constant width of the cross section, which do not have fastenings from the plane along the edge stretched from the moment, or with the coefficient according to the formula (23) should be multiplied by an additional coefficient. The values are given in Table 2, Appendix 4. At =1.

When reinforcing from the bending plane at intermediate points of the stretched edge of the element in the section, the coefficient determined by formula (23) should be multiplied by the coefficient:

:= (24)

		the central angle in radians that defines the section of the element of circular shape (for rectilinear elements);
		the number of intermediate reinforced (with the same step) points of the stretched edge on the section (for the value should be taken equal to 1).

4.15. Checking the stability of the flat form of deformation of bending elements of an I-beam or box-shaped cross-section should be carried out in cases where

width of the compressed belt of the cross section.

The calculation should be made according to the formula

		coefficient of longitudinal bending from the plane of bending of the compressed chord of the element, determined according to clause 4.3;
		design compressive strength;
		gross modulus of the cross section; in the case of plywood walls, the reduced modulus of resistance in the bending plane of the element.

Elements subjected to axial force with bending

4.16. Calculation of eccentric-tensioned and tension-bent elements should be made according to the formula

(27)

4.17. Calculation for the strength of eccentrically compressed and compressed-bent elements should be made according to the formula

(28)

Notes: 1. For hinged elements with symmetrical diagrams

bending moments sinusoidal, parabolic, polygonal

and close to them outlines, as well as for console elements should

determine by formula

			coefficient varying from 1 to 0, taking into account the additional moment from the longitudinal force due to the deflection of the element, determined by the formula
		bending moment in the design section without taking into account the additional moment from the longitudinal force;
		coefficient determined by formula (8) p.4.3.

2. In cases where bending moment diagrams in hinged elements have a triangular or rectangular shape, the coefficient according to formula (30) should be multiplied by the correction factor:

(31)

3. With an asymmetric loading of hinged elements, the magnitude of the bending moment should be determined by the formula

(32)

		bending moments in the calculated section of the element from the symmetrical and skew-symmetric components of the load;
		coefficients determined by formula (30) at slenderness values corresponding to symmetrical and oblique buckling forms.

4. For elements of a section variable in height, the area in formula (30) should be taken for the maximum section in height, and the coefficient should be multiplied by the coefficient taken according to Table 1, Appendix 4.

5. When the ratio of stresses from bending to stresses from compression is less than 0.1, the compressively-bent elements should also be checked for stability according to formula (6) without taking into account the bending moment.

4.18. The calculation for the stability of the flat form of deformation of the compressed-bent elements should be carried out according to the formula

(33)

		gross area with the maximum dimensions of the section of the element on the site ;

		for elements without fixing the stretched zone from the deformation plane and for elements having such fixings;
		buckling coefficient determined by formula (8) for the flexibility of the section of the element with the estimated length from the plane of deformation;
		coefficient determined by formula (23).

If there are fastenings in the element in the area from the deformation plane on the side of the edge stretched from the moment, the coefficient should be multiplied by the coefficient determined by the formula (24), and the coefficient - by the coefficient by the formula

(34)

When calculating elements of a section with a variable height that do not have fastenings from the plane along an edge stretched from the moment or at , the coefficients and determined by formulas (8) and (23) should be additionally multiplied, respectively, by the coefficients and given in Tables 1 and 2 appendix .4. At

4.19. In composite compressed-bent elements, the stability of the most stressed branch should be checked, if its estimated length exceeds seven branch thicknesses, according to the formula

(35)

The stability of a compressively-bent composite element from the bending plane should be checked using formula (6) without taking into account the bending moment.

4.20. The number of bond cuts , evenly spaced in each seam of a compressed-bent composite element in a section with an unambiguous diagram of transverse forces when a compressive force is applied over the entire section, must satisfy the condition

where the coefficient is taken from Table 1, Appendix 4.

	gross static moment of the shifted part of the cross section relative to the neutral axis; with hinged ends, as well as with hinged fastening at intermediate points of the element - 1; with one hinged and the other pinched end - 0.8; with one pinched and other free loaded end - 2.2; with both pinched ends - 0.65. In the case of a longitudinal load distributed evenly along the length of the element, the coefficient should be taken equal to: with both hinged ends - 0.73; with one pinched and the other free end - 1.2. The estimated length of intersecting elements connected to each other at the intersection should be taken equal to: when checking stability in the plane of structures - the distance from the center of the node to the point of intersection of the elements; when checking stability from the plane of the structure: a) in case of intersection of two compressed elements - the full length of the element;	Name of structural elements	Ultimate Flexibility

1. Compressed chords, support braces and truss support posts, columns
2. Other compressed elements of trusses and other through structures
3. Compressed link elements
4. Stretched truss belts in the vertical plane
5. Other tension elements of trusses and other through structures
For overhead power lines

The value should be taken at least 0.5;

c) in the case of intersection of a compressed element with a stretched element of equal magnitude - the greatest length of the compressed element, measured from the center of the node to the point of intersection of the elements.

If the intersecting elements have a composite section, then the corresponding slenderness values determined by formula (11) should be substituted into formula (37).

4.22. Flexibility of elements and their individual branches in wooden structures should not exceed the values specified in Table 14.

Features of the calculation of glued elements

plywood with wood

4.23. The calculation of glued elements made of plywood with wood should be carried out according to the reduced cross-section method.

4.24. The strength of the stretched plywood sheathing of slabs (Fig. 3) and panels should be checked according to the formula

moment of section modulus reduced to plywood, which should be determined in accordance with the instructions of clause 4.25.

4.25. The reduced modulus of the cross section of glued plywood boards with wood should be determined by the formula

distance from the center of gravity of the reduced section to the outer edge of the skin;

Fig.3. Cross section of glued plywood and wood boards

static moment of the shifted part of the reduced section relative to the neutral axis;

design chipping resistance of wood along the fibers or plywood along the fibers of the outer layers;

the calculated section width, which should be taken equal to the total width of the frame ribs.

A column is a vertical element of a building's load-bearing structure that transfers loads from higher structures to the foundation.

When calculating steel columns, it is necessary to be guided by SP 16.13330 " Steel structures».

For a steel column, an I-beam, a pipe, a square profile, a composite section of channels, corners, sheets are usually used.

For centrally compressed columns, it is optimal to use a pipe or a square profile - they are economical in terms of metal mass and have a beautiful aesthetic appearance, however, the internal cavities cannot be painted, so this profile must be airtight.

The use of a wide-shelf I-beam for columns is widespread - when the column is pinched in one plane, this type of profile is optimal.

Of great importance is the method of fixing the column in the foundation. The column can be hinged, rigid in one plane and hinged in another, or rigid in 2 planes. The choice of fastening depends on the structure of the building and is more important in the calculation, because. the estimated length of the column depends on the method of fastening.

It is also necessary to take into account the method of fastening the runs, wall panels, beams or trusses on a column, if the load is transferred from the side of the column, then the eccentricity must be taken into account.

When the column is pinched in the foundation and the beam is rigidly attached to the column, the calculated length is 0.5l, but 0.7l is usually considered in the calculation. the beam bends under the action of the load and there is no complete pinching.

In practice, the column is not considered separately, but a frame or a 3-dimensional building model is modeled in the program, it is loaded and the column in the assembly is calculated and the required profile is selected, but in programs it can be difficult to take into account the weakening of the section by bolt holes, so it may be necessary to check the section manually .

To calculate the column, we need to know the maximum compressive / tensile stresses and moments that occur in key sections, for this we build stress diagrams. In this review, we will consider only the strength calculation of the column without plotting.

We calculate the column according to the following parameters:

1. Tensile/compressive strength

2. Stability under central compression (in 2 planes)

3. Strength under the combined action of longitudinal force and bending moments

4. Checking the ultimate flexibility of the rod (in 2 planes)

1. Tensile/compressive strength

According to SP 16.13330 p. 7.1.1 strength calculation of steel elements with standard resistance R yn ≤ 440 N/mm2 in case of central tension or compression by force N should be carried out according to the formula

A n is the cross-sectional area of the net profile, i.e. taking into account the weakening of its holes;

R y is the design resistance of rolled steel (depends on the steel grade, see Table B.5 of SP 16.13330);

γ c is the coefficient of working conditions (see Table 1 of SP 16.13330).

Using this formula, you can calculate the minimum required cross-sectional area of \u200b\u200bthe profile and set the profile. In the future, in the verification calculations, the selection of the section of the column can be done only by the method of selection of the section, so here we can set the starting point, which the section cannot be less than.

2. Stability under central compression

Calculation for stability is carried out in accordance with SP 16.13330 clause 7.1.3 according to the formula

A- the cross-sectional area of the gross profile, i.e. without taking into account the weakening of its holes;

φ is the coefficient of stability under central compression.

As you can see, this formula is very similar to the previous one, but here the coefficient appears φ , in order to calculate it, we first need to calculate the conditional flexibility of the rod λ (denoted with a dash above).

where R y is the design resistance of steel;

E- elastic modulus;

λ - the flexibility of the rod, calculated by the formula:

where l ef is the calculated length of the rod;

i is the radius of inertia of the section.

Effective lengths l ef columns (pillars) of constant cross section or individual sections of stepped columns in accordance with SP 16.13330 clause 10.3.1 should be determined by the formula

where l is the length of the column;

μ - effective length coefficient.

Effective length factors μ columns (pillars) of constant cross section should be determined depending on the conditions for fixing their ends and the type of load. For some cases of fixing the ends and the type of load, the values μ are shown in the following table:

The radius of gyration of the section can be found in the corresponding GOST for the profile, i.e. the profile must be pre-specified and the calculation is reduced to enumerating the sections.

Because radius of gyration in 2 planes for most profiles has different values in 2 planes ( same values only have a pipe and a square profile) and the fixing can be different, and consequently the calculated lengths can also be different, then the calculation for stability must be made for 2 planes.

So now we have all the data to calculate the conditional flexibility.

If the ultimate flexibility is greater than or equal to 0.4, then the stability coefficient φ calculated by the formula:

coefficient value δ should be calculated using the formula:

odds α and β see table

Coefficient values φ , calculated by this formula, should be taken no more than (7.6 / λ 2) at values of conditional flexibility over 3.8; 4.4 and 5.8 for section types a, b and c, respectively.

For values λ < 0,4 для всех типов сечений допускается принимать φ = 1.

Coefficient values φ are given in Appendix D to SP 16.13330.

Now that all the initial data are known, we calculate according to the formula presented at the beginning:

As mentioned above, it is necessary to make 2 calculations for 2 planes. If the calculation does not satisfy the condition, then we select new profile with more great value radius of gyration of the section. It is also possible to change the design scheme, for example, by changing the hinged attachment to a rigid one or by fixing the column in the span with ties, the estimated length of the rod can be reduced.

Compressed elements with solid walls of an open U-shaped section are recommended to be reinforced with planks or gratings. If there are no straps, then the stability should be checked for stability in the bending-torsional form of buckling in accordance with clause 7.1.5 of SP 16.13330.

3. Strength under the combined action of longitudinal force and bending moments

As a rule, the column is loaded not only with an axial compressive load, but also with a bending moment, for example, from the wind. The moment is also formed if the vertical load is applied not in the center of the column, but from the side. In this case, it is necessary to make a verification calculation in accordance with clause 9.1.1 of SP 16.13330 using the formula

where N- longitudinal compressive force;

A n is the net cross-sectional area (taking into account weakening by holes);

R y is the design resistance of steel;

γ c is the coefficient of working conditions (see Table 1 of SP 16.13330);

n, Сx and Сy- coefficients taken according to table E.1 of SP 16.13330

Mx and My- moments relative to axes X-X and Y-Y;

W xn,min and W yn,min - section modulus relative to the X-X and Y-Y axes (can be found in GOST on the profile or in the reference book);

B- bimoment, in SNiP II-23-81 * this parameter was not included in the calculations, this parameter was introduced to account for warping;

Wω,min – sectoral section modulus.

If there should be no questions with the first 3 components, then accounting for the bimoment causes some difficulties.

The bimoment characterizes the changes introduced into the linear zones of the stress distribution of the deformation of the section and, in fact, is a pair of moments directed in opposite directions

It is worth noting that many programs cannot calculate the bimoment, including SCAD does not take it into account.

4. Checking the ultimate flexibility of the rod

Flexibility of compressed elements λ = lef / i, as a rule, should not exceed the limit values λ u given in the table

The coefficient α in this formula is the utilization factor of the profile, according to the calculation of the stability under central compression.

As well as the stability calculation, this calculation must be done for 2 planes.

If the profile does not fit, it is necessary to change the section by increasing the radius of gyration of the section or changing the design scheme (change the fastenings or fix with ties to reduce the estimated length).

If the critical factor is the ultimate flexibility, then the steel grade can be taken as the smallest. the steel grade does not affect the ultimate flexibility. The best option can be calculated by selection.

Posted in Tagged ,

Initially, metal, as the most durable material, served protective purposes - fences, gates, gratings. Then they began to use cast-iron poles and arches. The expanded growth of industrial production required the construction of structures with large spans, which stimulated the appearance of rolled beams and trusses. As a result, the metal frame became a key factor in the development architectural form, as it allowed to free the walls from the function of the supporting structure.

Central tension and central compression steel elements. Calculation of the strength of elements subject to central tension or compression by force N, should be done according to the formula

where is the calculated resistance of steel to tension, compression, bending in terms of yield strength; is the net cross-sectional area, i.e. area minus the weakening of the section; - coefficient of working conditions, taken according to the tables of SNIP N-23-81 * "Steel structures".

Example 3.1. A hole with a diameter of d= = 10 cm (Fig. 3.7). I-beam wall thickness - s- 5.2 mm, gross cross-sectional area - cm2.

It is required to determine the allowable load that can be applied along the longitudinal axis of the weakened I-beam. The design resistance began to take kg / cm2, and.

Decision

We calculate the net cross-sectional area:

where is the gross sectional area, i.e. the total cross-sectional area, excluding weakening, is taken in accordance with GOST 8239–89 "Hot-rolled steel I-beams".

Determine the allowable load:

Determining the absolute elongation of a centrally tensioned steel bar

For a bar with a step change in cross-sectional area and normal force, the total elongation is calculated by algebraic summation of the elongations of each section:

where P - number of plots; i- lot number (i = 1, 2,..., P).

The elongation from the own weight of a rod of constant section is determined by the formula

where γ is the specific gravity of the rod material.

Sustainability calculation

Calculation for the stability of solid-walled elements subject to central compression by force N, should be performed according to the formula

where A is the gross sectional area; φ - coefficient of buckling, taken depending on the flexibility

Rice. 3.7.

and design resistance of steel according to the table in SNIP N-23–81 * "Steel structures"; μ is the length reduction factor; – minimum radius of gyration cross section; Flexibility λ of compressed or tensioned elements should not exceed the values given in SNIP "Steel structures".

The calculation of composite elements from angles, channels (Fig. 3.8), etc., connected closely or through gaskets, should be performed as solid-walled, provided that the largest clear distances in the areas between the welded strips or between the centers of the extreme bolts do not exceed for compressed elements and for stretched elements.

Rice. 3.8.

Bending steel elements

The calculation of beams bent in one of the main planes is performed according to the formula

where M - maximum bending moment; is the net section modulus.

The values of shear stresses τ in the middle of the bending elements must satisfy the condition

where Q- transverse force in section; - static moment of half the section relative to the main axis z;- axial moment of inertia; t– wall thickness; – design shear resistance of steel; - the yield strength of steel, adopted according to state standards and specifications for steel; - reliability factor for the material, adopted according to SNIP 11-23-81 * "Steel structures".

Example 3.2. It is required to select the cross section of a single-span steel beam loaded with a uniformly distributed load q= 16 kN/m, can length l= 4 m, , MPa. The cross section of the beam is rectangular with a height ratio h to width b beams equal to 3 ( h/b = 3).

Calculation of elements of wooden structuresby limit states of the first group

Centrally stretched and centrally compressed elements

6.1 The calculation of centrally tensioned elements should be made according to the formula

where is the calculated longitudinal force;

Estimated wood tensile strength along the fibers;

The same for unidirectional veneer wood (5.7);

The cross-sectional area of the net element.

When determining attenuation, located in a section up to 200 mm long, should be taken combined in one section.

6.2 The calculation of centrally compressed elements of a constant solid section should be made according to the formulas:

a) strength

b) stability

where is the calculated resistance of wood to compression along the fibers;

The same for unidirectional veneer wood;

Buckling coefficient determined according to 6.3;

Net cross-sectional area of the element;

The calculated cross-sectional area of the element, taken equal to:

in the absence of weakening or weakening in dangerous sections that do not extend to the edges (Figure 1, a), if the weakening area does not exceed 25%, where is the gross sectional area; for weakenings that do not extend to the edges, if the weakening area exceeds 25%; with symmetrical weakening that goes to the edges (Figure 1, b),.

a- not facing the edge; b- facing the edge

Picture 1- Loosening compressed elements

6.3 The buckling coefficient should be determined by the formulas:

with element flexibility 70

where the coefficient is 0.8 for wood and 1.0 for plywood;

factor 3000 for wood and 2500 for plywood and unidirectional veneer wood.

6.4 The flexibility of solid section elements is determined by the formula

where is the estimated length of the element;

The radius of gyration of the section of the element with the maximum gross dimensions relative to the axis.

6.5 The estimated length of the element should be determined by multiplying its free length by the coefficient

according to 6.21.

6.6 Composite elements on pliable joints, supported by the entire cross section, should be calculated for strength and stability according to formulas (8) and (9), while they should be determined as the total areas of all branches. The flexibility of the constituent elements should be determined taking into account the compliance of the joints according to the formula

where is the flexibility of the entire element relative to the axis (Figure 2), calculated from the estimated length of the element without taking into account compliance;

* - flexibility of a separate branch relative to the I-I axis (see Figure 2), calculated from the estimated length of the branch; at less than seven thicknesses () of the branch are taken c0*;

The coefficient of reduction of flexibility, determined by the formula

* The formula and its explication correspond to the original. - Database manufacturer's note.

where u is the width and height of the cross section of the element, cm;

Estimated number of seams in an element, determined by the number of seams over which the mutual shift of elements is summed up (in Figure 2, a- 4 seams, in figure 2, b- 5 stitches);

Estimated element length, m;

Estimated number of cuts of bonds in one seam per 1 m of the element (for several seams with a different number of cuts, the average number of cuts for all seams should be taken);

Compliance coefficient of joints, which should be determined using the formulas in Table 15.

a- with gaskets b- without pads

Figure 2- Components

Table 15


Relationship type	Coefficient at
Relationship type	central compression	bending compression
1 Nails, screws
2 Steel cylindrical dowels
a) the diameter of the thickness of the connected elements
b) the diameter of the thickness of the connected elements
3 Glued-in rebars A240-A500
4 Oak cylindrical dowels
5 Oak lamellar dowels

Note - The diameters of nails, screws, dowels and glued rods, the thickness of the elements, the width and thickness of the lamellar dowels should be taken in cm.

When determining the diameter of nails, no more than 0.1 of the thickness of the connected elements should be taken. If the size of the pinched ends of the nails is less, then the cuts in the seams adjacent to them are not taken into account in the calculation. The value of connections on steel cylindrical pins should be determined by the thickness of the thinnest of the connected elements.

When determining the diameter of oak cylindrical dowels, no more than 0.25 of the thickness of the thinner of the connected elements should be taken.

The flexibility of a composite element, calculated by formula (11), should be taken no more than the flexibility of individual branches, determined by the formula:

where is the sum of the gross moments of inertia of the cross sections of individual branches relative to their own axes parallel to the axis (see Figure 2);

Gross section area of the element;

Estimated element length.

The flexibility of a composite element with respect to the axis passing through the centers of gravity of the sections of all branches (the axis in Figure 2) should be determined as for a solid element, i.e. without taking into account the compliance of the bonds, if the branches are loaded evenly. In the case of unevenly loaded branches, one should be guided by 6.7.

If the branches of a composite element have a different cross section, then the calculated flexibility of the branch in formula (11) should be taken equal to

the definition is shown in figure 2.

6.7 Composite elements on pliable joints, some of the branches of which are not supported at the ends, can be calculated for strength and stability according to formulas (5), (6) subject to the following conditions:

a) the cross-sectional area of the element should be determined by the cross section of the supported branches;

b) the flexibility of the element relative to the axis (see Figure 2) is determined by the formula (11); in this case, the moment of inertia is taken taking into account all branches, and the area - only supported ones;

c) when determining the flexibility relative to the axis (see Figure 2), the moment of inertia should be determined by the formula

where u are the moments of inertia of the cross sections of the supported and unsupported branches, respectively.

6.8 The calculation for the stability of centrally compressed elements of a section with a variable height should be performed according to the formula

where is the gross cross-sectional area with maximum dimensions;

Coefficient taking into account the variability of the section height, determined according to Table E.1 of Appendix E (for elements of a constant section1);

The buckling factor determined in accordance with 6.3 for the slenderness corresponding to the section with the maximum dimensions.

total area (gross)- The cross-sectional area of a stone (block) without deducting the areas of voids and protruding parts. [English Russian Dictionary for the Design of Building Structures. MNTKS, Moscow, 2011] Topics building construction EN gross area …

bolt gross area- A - [English Russian Dictionary of Structural Design. MNTKS, Moscow, 2011] Topics building structures Synonyms A EN gross cross section of a bolt … Technical Translator's Handbook

bearing part- 3.10 bearing part: An element of a bridge structure that transfers the load from the superstructure and provides the necessary angular and linear displacements of the supporting nodes of the superstructure. Source: STO GK Transstroy 004 2007: Metal ... ...

GOST R 53628-2009: Metal roller bearings for bridge building. Specifications- Terminology GOST R 53628 2009: Metal roller bearings for bridge building. Specifications original document: 3.2 span length: The distance between the extreme structural elements of the span, measured according to ... Dictionary-reference book of terms of normative and technical documentation

Masonry structures made of natural or artificial stones. NATURAL STONES natural stones masonry from such stones gives the architect more opportunities ... ... Collier Encyclopedia

Terminology 1: : dw Number of the day of the week. "1" corresponds to Monday Term definitions from various documents: dw DUT Difference between Moscow and UTC, expressed as an integer number of hours Term definitions from ... ... Dictionary-reference book of terms of normative and technical documentation

- (USA) (United States of America, USA). I. General information USA is a state in North America. The area is 9.4 million km2. Population 216 million people (1976, est.). Capital city of Washington. Administratively, the territory of the United States ...

GOST R 53636-2009: Pulp, paper, cardboard. Terms and Definitions- Terminology GOST R 53636 2009: Pulp, paper, cardboard. Terms and definitions original document: 3.4.49 absolutely dry mass: The mass of paper, cardboard or pulp after drying at a temperature of (105 ± 2) ° C to constant weight under conditions ... ... Dictionary-reference book of terms of normative and technical documentation

Hydroelectric power station (HPP), a complex of structures and equipment through which the energy of the flow of water is converted into electrical energy. HPP consists of a series circuit hydraulic structures(See Hydraulic engineering ... ... Great Soviet Encyclopedia

- (until 1935 Persia) I. General information I. state in Western Asia. It borders in the north with the USSR, in the west with Turkey and Iraq, in the east with Afghanistan and Pakistan. It is washed in the north by the Caspian Sea, in the south by the Persian and Oman gulfs, in ... ... Great Soviet Encyclopedia

snip-id-9182: Technical specifications for types of work in the construction, reconstruction and repair of roads and artificial structures on them- Terminology snip id 9182: Technical specifications for types of work in construction, reconstruction and repair highways and artificial structures on them: 3. Asphalt distributor. It is used to strengthen asphalt concrete granulate ... ... Dictionary-reference book of terms of normative and technical documentation