Steel

This mode is used to select a steel grade for the designed structure. The choice is made for four groups of structures according to

• Table 50* of SNiP II-23-81*;
• ShNK 2.03.05-13;
• Annex C of SP 53-102-2004;
• Annex C of SP 16.13330;
• Annex F of DBN B.2.6-163:2010;
• Annex D of DBN B.2.6-198:2014.

The procedure for classifying a structure into a certain group is described in the paper by Gildergorn & Perelmuter and in DBN B.2.6-163:2010.

The Application Conditions tab contains six groups of data.

In the Importance class according to GOST 27751 group you should select one of the four cases defined in the codes, keeping in mind that the importance factor, γ_n, for unique projects is, as a rule, defined individually for each particular project by an institution which gives an approval of the design. To implement this procedure, use the Application Settings dialog box. The default value for the objects of the said type is γ_n = 1.2.

The Possible consequences of achieving the limit state group enables to select one of the three importance classes of the considered structural member. The paper of Gildergorn & Perelmuter provides recommendations on how to classify some structures into these classes (Classes A, B, and C correspond to three grades in the considered group). This rating is accurate for DBN but can be used in other cases as well.

Necessary extracts from these recommendations are given below.

Structures of service platforms and decks:

• main and secondary beams, girders of frames — A;
• metal sheeting — B.

Columns of industrial buildings and open crane trestles:

• columns of service platforms and decks — A;
• main members of the cross-section — A;
• main vertical bracings between columns — A;
• bracings with the stress below 0.4R_y — C.

Roofing structures:

• trusses, girders — A;
• skylight panels, roof panels, purlins, longitudinal bracings — B;
• other bracings — C.

Framework structures:

• girders under brick walls and above gates — A;
• columns, end and wind trusses — B;
• other members — C.

Auxiliary structures:

• stringers — A;
• landings, imposts, window and skylight casements — C.

Conveyor galleries:

• span structures, column bracings — A;
• other bracings, roof beams, framework members — B.

Supports of power transmission lines and structures of outdoor switch-gears (OSG):

• supports of power transmission lines, pylons for OSG switches — A;
• pylons for other OSG equipment — B.

Aerial equipment:

• trunks of masts and towers — A;
• diaphragms of towers, stairways, landings — B.

Vents and chimneys:

• chords and lattices of towers, shell of a separate pipe — A;
• flue-gas stacks, pipe shells with bracings — B;
• decks, mantles, stiffeners — C.

Cooling towers, water towers:

• chords of lattice towers, lattices — A;
• framework, decks, covering of cooling towers — C.

Bunkers, silos — A.

Other groups serve to characterize the stressed state (Presence of tension under design load and Tensile stresses caused by dynamic loads), and to indicate the temperature mode of operation (Climatic region according to GOST 16350-80). The latter group requires that you indicate whether there is welding in the tension area (Welding in places of tension that exceeds 30% of the design strength).

Once you have filled all data in the first tab, click on the Structural Steels and Plates or Pipes tab to open the respective tab of the dialog box.

Tabs contain a reference to a group of structures according to

• Table 50* of SNiP II-23-81*;
• Annex C of SP 53-102-2004;
• Annex C of SP 16.13330;
• Annex C of DBN B.2.6-163:2010;
• Annex A of DBN B.2.6-198:2014,

which conforms to operating conditions specified on the previous tab, a list of steel grades recommended for this group according to GOST 27772-88, and a list of steel grades according to other standards or codes which can be used instead of the recommended steel. This tab also provides reference data on the design strength based on the yield strength (R_y) and on the ultimate strength (R_u).

Steels are selected from one of the following groups: structural steels and plates and steels for hot rolled pipes selected according to the Table 51* of SNiP II-23-81* or according to the Table C6 of SP 53-102-2004, SP 16.13330, Table F.1 of DBN B.2.6-163:2010, Table D.1 of DBN B.2.6-198:2014.

A certain group of structures may require steel of a better grade than that recommended by SNiP or SP. Therefore the user can increase (by no means decrease!) the group of structures by selecting its number from the respective drop-down list. Obviously, the list of recommended steel grades will change as well.

The Apply button is used to transfer the properties of the selected steel grade to the active design mode (from which the Steel mode has been invoked). These properties will be used to assess the load-bearing capacity, and they can be modified in the Application Settings dialog box.

It should be noted that the application does not list all the details which are obligatory to include in the order on steel, such as in notes to Tables 50* and 51, b of SNiP II-23-81* and notes to text and tables of the Annex C of SP 53-102-2004 or SP 16.13330 and Annex F of DBN B.2.6-163:2010 and D of DBN B.2.6-198:2014. Primary regulatory codes and specifications should be used to create an order.