RCS 91.040.
Amendment 1
to SR 20.13330.2011 "SNiP 2.01.07-85* Loads and actions
1. Clause "g) other emergency exposures which may cause the structural elements fracture" shall be added to Article 5.5 after clause f). 2. Article 6.5. In the end of the second paragraph, content "short duration loads may be not taken into consideration" shall be deleted, and said paragraph shall be paraphrased as follows: "The lower values of the short duration loads shall be considered in cases when loads are applied in specific combinations, including explosion loads caused by fire, transport impact on the structural parts or other emergency exposures". 3. Article 9.8 shall be reworded as follows: "9.8 For crane loads, the load effect factor shall be taken as equal to γ f = 1.2 under all operational modes, including the local beam web stability check. 4. Article 9.10 shall be deleted. 5. In Article 10.1, formula (10.1) shall be written as:
S 0 = ce ct µ Sg,
(10.1)
6. In Article 10.1, the last paragraph shall be reworded as follows: "Sg - standard weight 2
value for snow cover per 1m of horizontal ground surface taken in accordance with 10.2". 7. Article 10.2 shall be reworded reworded as follows: "standard weight weight value for snow cover Sg per 2
1m of horizontal ground surface shall be taken in accordance with the snow zones of the Russian Federation given in Table 10.1.
1
Table 10. 1
Snow zones
I
II
III
IV
V
VI
VII
VIII
I
II
III
IV
V
VI
VII
VIII
0.6
0.9
1.3
1.8
2.3
2.8
3.4
4.0
(taken by map 1 of Annex G) Snow zones (taken by map 1 of Annex G) Sg , kPa
For mountainous and poorly explored regions indicated on Map 1, Annex G, rugged topography areas, or in cases when the standard weight value for snow cover is determined by the local meteorological station generated data (see 4.4), Sg shall be calculated by formula Sg = 0,7Sg,25 , where Sg,25
- the annual snow cover weight maximum, exceeded once per 25 rears on average
and calculated on the basis of data received from the water supply inspection aimed snow surveys within areas protected from direct wind impacts in accordance with the established procedure". For settlements placed in regions with local terrain height variations over 500m, the weight value of snow cover shall be adjusted according to the height parameter". 8. Article 10.3. The following note shall be added: "Note: For structural diagrams for roofs sensitive to local inequality of snow load distribution (for example, diagrams D.1, D.2, D.5, D.6 of Annex D), consideration of additional snow load distribution diagrams, in which the values of µ coefficients for adjoining spans change at a pitch of ±10%, is advisable." 9. In Article 10.4, note 2 shall be reworded as follows: "2 In cases when the snow load distribution diagrams for coatings have not been provided in
Annex D, for example, for complex geometry shell roofs and roofs for which the minimum typical plan size exceeds 100 m, these diagrams are usually set in special recommendations and developed on the basis of the wind tunnel model test results". 10. In Article 10.4, Note 3 shall be reworded as follows: "3 Standard value for snow load S0 given in Annex D shall be taken with e, t and µ coefficient
values equal to 1". 11. Note 5 shall be added to Article 10.4: "5 When making calculations for roof bearers, the local irregularity of snow deposition shall be considered by adding extra coefficient µ = 1.1 to the rated values of evenly distributed snow load." 2
12. Article 10.5 shall be reworded as follows: "For low-profile roofs (with slope ≤ 12% or f/l ≤ 0.05) of single- or multi-span buildings with no luminaries, designed for utilization in regions with average wind speed V ≥ 4 m/s, as rated during the three coldest months (see diagrams D.1, D.2, D.5 and D.6 of Annex D) and located in an exposed area, the snow drifting coefficient shall be set according to formula (10.2) but no less than 0.5 and no greater than 1.0.
� �,� − �,�√�,� + �,���,
(10.2)
, where k – is taken for types of locality or B (see 11.1.6) according to Table 11.2;
b – typical size of roof in the considered direction of snow drifting, t aken as ≤ 100 m". 13. Clause b) of Article 10.9 shall be reworded as follows: "b) for construction roofs, protected from the direct wind impact by, including: higher neighbouring buildings, continuous structural elements dominating at two or more sides, higher forested areas, as well as for roofs located below surrounding area;" 14. The last paragraph of Article 11 shall be reworded as follows: "Resonant vortex excitation and unstable galloping type aerodynamically-forced vibrations shall be considered for buildings and solid-walled structures, for which λ > 5, where λ has been defined in E.1.15." 15. Article 11.3.1 shall be reworded as follows: "Buildings and structures conforming to the condition of λ > 5, are subject to structural re-calculation for resonant vortex excitation; in this case λ is defined in E.1.15". 16. Annex E. Clause D.8, d). In the end of the clause, the following content shall be added after the formula for b and words "but no greater than 5 h and no greater than 16 m": ",where µ is taken from clause b)". 17. Annex D. Clause D.8, d) shall be reworded as follows:
"e) the values of µ coefficients used for calculations shall not exceed: (where h – in m; S0 – in kPa);
4 – when inner coating serves as the building roof, and l1 ′ and l2′ ≤ 48 m ; 6 – when inner coating serves as the building fore-roof or roof, and l1′ or l2′ > 72 m . Intermediate
values of µ shall be determined by interpolation from the largest value of l1′ or l2′." 18. Annex E. Clause D.8, f) shall be reworded as follows: f) µ1 coefficient shall be accepted as: µ � − � �, at � ′
� and for roofs without guard railing µ ≤ ;
3
,
� � − , − ℎ at , � and ≤ - for roofs with guard railing, where µ is taken from
clause e)b but no less than 0.2
�
′ , – in other cases, where µ is taken from clause e)b but no less than 0.2 ′ ,
19. Note 4 shall be added to clause D.8 in the follo wing wording: "4 In case of presence of continuous guard railing with height h (m) at the point of the outer coating level difference, greater than 0.5 S0 (kPa), m1 can be taken as equal to 0". 20. Annex E. Table E.4. Note 4 shall be added: "4 For horizontal fore-roofs, the two loading alternatives corresponding to diagrams III and IV shall be considered, with α=10°". 21. Annex E. In clause E.1.12, the sixth paragraph and Figure E.18 shall be reworded as follows: "Aerodynamic drag coefficients for sloping elements (Figure E.18) shall be determined by the formula:
cx β = cx sin2 β
where cx – is determined according to the data shown in Figure E.17 ; β – angle between the element axis and the speed of wind V directed along axis x."
22. Annex E. In clause E.1.14, the first paragraph standing after the formula shall be reworded as follows: " xi – the aerodynamic coefficient for i-th structural element, taken for sections as equal to 1.4 ( xi= 1,4) and determined for elements with circular or rectangular sections in accordance with the instructions of E.1.12 and E.1.13 correspondingly; with k λ =1;"
4
23. Indicated misprints have been corrected.
Director, V.A. Kucherenko Central Research Institute of Building and Construction – Scientific Research Centre “Stroitelstvo”, OJSC
Vedyakov I.I.
Executive officer, Chief of Construction Reliability Laboratory
Popov N..
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