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4.4. Recommendations about calculation reinforced-concrete ploskonaprjazhennyh korrozionno the damaged designs of integral sectional view with cracks

The carried out experimental and numerical researches allow to formulate some offers on designing of new types of reinforced-concrete integral designs and constructive systems, with such designs, at various sorts and weighting modes.

Besides now there is a necessity of calculation of constructive systems not only on traditionally accepted limiting conditions I and II groups, but also a so-called other-wordly condition caused by special impacts [193].

Recommendations and offers on designing of reinforced-concrete integral designs and constructive systems:

1. The sizes of characteristic elements of a seam of contact of an integral design are accepted equal to width of an interface and depend on properties of materials forming contact. The interface sizes are defined under the formula:

(4-27)

Where - making parts of an interface of the contacting

Concrete (fig. 4.10).

Drawing 4.10 - To definition of width of an interface ∆b

For integral designs with not reinforced seam of contact the width making parts of an interface of one of contacting concrete is defined under the formula:

Where - the relation bolshego to smaller elastic moduluses

The materials forming contact, is accepted no more: 1,7 - for heavy concrete and 3,5 - for easy concrete; h - length of an interface; p - the factor accepted for a concrete of high specific weight п=1, for a lightweight-aggregate concrete n=0,5.

For integral designs with a reinforced seam of contact the width making parts of an interface of one of contacting concrete is accepted equal to two diameters of a reinforcing bar.

2. Durability of concrete on a seam of contact of an integral design is accepted equal durability of one of contacting concrete having smaller a class on durability with the lowering factor depending on the selected constructive decisions. Lowering

At durability appointment (Rbi, Rbt ∣, Eb,) concrete of a characteristic element of a seam of contact it is necessary to accept factor:

For designs with a monolithic seam of contact (fig. 4.11а) equal 0,4;

For designs with a monolithic reinforced seam (fig. 4.11) equal 1,0;

For designs with a pliable reinforced seam (fig. 4.116) equal 0,7;

Drawing 4.11 - Constructive decisions of a seam of contact of an integral design: a monolithic seam (), a monolithic seam with a transverse reinforcement (), a pliable seam with a transverse reinforcement ()

3. Check treshchinostojkosti and durabilities of characteristic elements is carried out by means of criteria crack NOSTOJ bones and durabilities in the form of elliptic curved lines (fig. 4.12) expressed through the main efforts in ploskonaprjazhennom a characteristic element (N ∣, N2) enclosed on level of a median surface:

Drawing 4.12 - the strength condition Schedule korrozionno the damaged concrete at a flat stress condition

At check greshinostojkosti characteristic elements of a seam of contact durability of concrete of these elements is accepted according to point 2 of the present recommendations.

4. The is intense-deformed condition of characteristic elements is defined, using modified inkrementalnuju I.I.Karpenko's model according to which communication between normal both tangent lines forces and deformations registers in a sort:

Where - relative deformations, - normal and

Force tangent lines, - nonlinear factors of a symmetric negative mould of a pliability of ferro-concrete.

For characteristic elements of a seam of contact after formation of a longitudinal crack along seam Tr. 1 (fig. 4.13) negative mould factors
Pliability [C ', J on increments of pressure and deformations is defined according to the following system of the equations:

For characteristic elements of a seam of contact to a longitudinal crack along seam Tr. 1 and a crack from main stretching stresses Тр.2 (fig. 4.12) factors of a negative mould of a pliability [Q] on increments of pressure and deformations are defined according to the following system of the equations:

Where Al, А2, AZ, Bl B2, VZ - the factors of the equations defined under formulas (2.87) - the average module of deformations of armature of a direction

At, defined under formulas (2.88); η - the factor considering the raised pliability of reinforcing bars to tangential movings in concrete at a crack η ≈ 16.

For other characteristic elements of an integral design before formation in them of cracks Тр.2, Tr. Z (fig. 4.13) factors of a symmetric negative mould of a pliability [With, at] are defined according to settlement model N of I.Karpenko [94].

Drawing 4.13 - General lay-outs of characteristic elements at various sorts of cracks in an integral design: only a horizontal crack in a contact seam (), crossed cracks of a seam of contact and slope (), slope and normal cracks ()

5. Definition of parametres of characteristic elements korrozionno the damaged reinforced concrete construction (R*bi, R*bti, E*b,) the being

Under the influence of an excited environment during the considered period of time t it is carried out on the following sequence:

1) depth of advancement in time of front of neutralisation of an excited environment in concrete is defined at sredovyh and power impacts:

2) check of characteristic elements on sectional view height, taking into account level and a stress condition sign, for definition of completely neutralised elements and elements in which there passes neutralisation border in time t is carried out.

3) factors of a chemical durability of a material for each characteristic element are calculated:

Where factors and and b the equations (4.36) pay off on test results using following formulas

Chemical durability and time of trials in і th series of samples; p - number of series of samples.

4) values of limiting durability on compression and a tensioning and the module of deformations for korrozionno the damaged characteristic elements under formulas are calculated:

For completely neutralised elements:

For partially neutralised elements:

- The area of the neutralised concrete in an element, - the area of "healthy" concrete in an element, St

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A source: Gubanova Maria Sergeevna. LONG WARPING PLOSKONAPRJAZHENNYH KORROZIONNO of the DAMAGED INTEGRAL REINFORCED CONCRETE CONSTRUCTIONS. The dissertation on competition of a scientific degree of a Cand.Tech.Sci. Kursk - 2018. 2018

More on topic 4.4. Recommendations about calculation reinforced-concrete ploskonaprjazhennyh korrozionno the damaged designs of integral sectional view with cracks:

  1. the Basic approaches and techniques to calculation reinforced-concrete ploskonaprjazhennyh designs of integral sectional view
  2. Construction of physical parities in inkrementalnoj to the form for reinforced-concrete integral designs with cracks in a working area of contact of two concrete at the scheme of crossed cracks
  3. Gubanova Maria Sergeevna. LONG WARPING PLOSKONAPRJAZHENNYH KORROZIONNO of the DAMAGED INTEGRAL REINFORCED CONCRETE CONSTRUCTIONS. The dissertation on competition of a scientific degree of a Cand.Tech.Sci. Kursk - 2018, 2018
  4. Physical models of a warping of reinforced concrete constructions of integral sectional view
  5. Construction of physical parities in inkrementalnoj to the form for reinforced-concrete integral designs with cracks in a working area of contact of two concrete at a flat stress condition
  6. a warping Model korrozionno the damaged reinforced-concrete element in inkrementalnoj to the form
  7. 2.3 Long warping korrozionno the damaged reinforced-concrete element on the basis of an anisotropic model
  8. the Analysis of experimentally-theoretical researches by definition of the resulted rigidness of reinforced-concrete integral designs on shear
  9. SECTION 4 SETTLEMENT MODELS AND NUMERICAL ANALYSIS KORROZIONNO DAMAGED REINFORCED-CONCRETE SOSTAVIYH КОНСТРУКЦІIИ
  10. SECTION 2. SETTLEMENT MODELS OF THE LONG WARPING OF REINFORCED-CONCRETE INTEGRAL DESIGNS AT SIMULTANEOUS DISPLAY POWER AND SREDOVYH IMPACTS
  11. Criterion treshinostojkosti loaded and korrozionno damaged concrete at a flat stress condition
  12. 4.3. The settlement analysis of a reinforced-concrete integral beam head panelnoyoramnogo a framing of a many-storeyed building at special impact
  13. the Strength condition loaded and korrozionno damaged concrete at a flat stress condition
  14. the Strength condition korrozionno damaged concrete at a flat stress condition
  15. Algorithms of definition of the is intense-deformed condition ferro-concrete sing integral ploskonaprjazhennoj designs with corrosion damages