Resistance of Sections

This mode enables to determine the load-bearing capacity of any cross-section available in the application. In the general case, the analyses are performed for a longitudinal force, bending moments and shear forces acting in the principal axes of inertia. The whole set of checks for strength, stability and slenderness is implemented in compliance with the selected design code, with the following exceptions:

bars in tension are not checked for strength by the design resistance, as members which can be used even after the yield point is reached;
the calculation of the effective slenderness values for lattice bars are performed according to more accurate formulas from Table 13 of the Guide to SNiP II-23-81*;
when calculating the φ_b coefficient, it is assumed that the load is uniformly distributed and applied to the compressed chord which is not restrained in its span against buckling. However, a special dialog box can be invoked by clicking the button $image\kristall_74.jpg$ , where you can select one of the rules for calculating this factor provided by the codes (the user is responsible for the consequences of this selection), or use the Default button to return to the standard behavior of the program (described above).

The set of checks depends on the type of the member cross-section and the set of loads it is subjected to.

Check	SNiP II-23-81*	SNiP RK5.04-23-2002	SP 53-102-2004	SP 16.13330	DBN B.2.6-163:2010	DBN B.2.6-198:2014	ShNK 2.03.05-13
Strength under axial tension/compression	Sec. 5.1	Sec. 5.1	Sec. 8.1.1	Sec. 7.1.1	Sec. 1.4.1.3	Sec. 8.1.3	Sec. 7.1
Excessive deformations of the tension fiber	Sec. 5.28	Sec. 5.28	Sec. 10.1.3	Sec. 9.1.3	Sec. 1.6.1.3	Sec. 10.1.3	Sec. 7.28
Strength under action of bending moment M_y	Sec. 5.12	Sec. 5.12	Sec. 9.2.1	Sec. 8.2.1	Sec. 1.5.2.1	Sec. 9.2.1	Sec. 7.12
Strength under action of bending moment M_z	Sec. 5.12	Sec. 5.12	Sec. 9.2.1	Sec. 8.2.1	Sec. 1.5.2.1	Sec. 9.2.1	Sec. 7.12
Strength under action of lateral force Q_y	Sec. 5.12, 5.18*	Sec. 5.12, 5.18	Sec. 9.2.1, 10.1.1	Sec. 8.2.1	Sec. 1.5.2.1	Sec. 9.2.1	Sec. 7.12, 7.18
Strength under action of lateral force Q_z	Sec. 5.12, 5.18*	Sec. 5.12, 5.18	Sec. 9.2.1, 10.1.1	Sec. 8.2.1	Sec. 1.5.2.1	Sec. 9.2.1	Sec. 7.12, 7.18
Strength under combined action of longitudinal force and bending moments	Sec. 5.24, 5.25	Sec. 5.24, 5.25	Sec. 10.1.1	Sec. 9.1.1	Sec. 1.6.1.1	Sec. 10.1.1	Sec. 7.24, 7.25
Strength under combined action of longitudinal force and bending moments, allowing for plasticity	Sec. 5.24, 5.25	Sec. 5.24, 5.25	Sec. 10.1.1	Sec. 9.1.1	Sec. 1.6.1.1	Sec. 10.1.1	Sec. 7.24, 7.25
Strength under combined action of longitudinal force and bending moments, no plasticity	Sec. 5.24, 5.25	Sec. 5.24, 5.25	Sec. 10.1.1	Sec. 9.1.1	Sec. 1.6.1.1	Sec. 10.1.1	Sec. 7.24, 7.25
Strength for reduced stresses at the simultaneous action of the bending moment and the lateral force	Sec. 5.14*	Sec. 5.14	Sec. 9.2.1	Sec. 8.2.1	Sec. 1.5.2.1	Sec. 9.2.1	Sec. 7.14
Stability under compression in XoY (XoU) plane	Sec. 5.3	Sec. 5.3	Sec. 8.1.3	Sec. 7.1.3	Sec. 1.4.1.3	Sec. 8.1.3	Sec. 9.4
Stability under compression in XoY (XoU) plane (post-buckling behavior)	Sec. 5.3, 7.20*	Sec. 5.3, 7.30	Sec. 8.1.3, 8.3.5	Sec. 7.1.3, 7.3.6	Sec. 1.4.1.3, 1.4.3.5	Sec. 8.1.3, 8.3.5	Sec. 9.4, 9.20
Stability under compression in XoZ (XoV) plane	Sec. 5.3	Sec. 5.3	Sec. 8.1.3	Sec. 7.1.3	Sec. 1.4.1.3	Sec. 8.1.3	Sec. 7.3
Stability under compression in XoZ (XoV) plane (post-buckling behavior)	Sec. 5.3, 7.20*	Sec. 5.3, 7.30	Sec. 8.1.3, 8.3.5	Sec. 7.1.3, 7.3.6	Sec. 1.4.1.3, 1.4.3.5	Sec. 8.1.3, 8.3.5	Sec. 7.3, 9.20
Stability in compression of angle	Sec. 5.3	Sec. 5.3	Sec. 8.1.3	Sec. 7.1.3	Sec. 1.4.1.3	Sec. 8.1.3	Sec. 7.3
Stability in the moment M_y plane under eccentric compression	Sec. 5.27*	Sec. 5.37	Sec. 10.2.9, 10.2.10	Sec. 9.2.9, 9.2.10	Sec. 1.6.2.9, 1.6.2.10	Sec. 10.2.9, 10.2.10	Sec. 7.27
Stability in the moment M_y plane under eccentric compression (post-buckling behavior)	Sec. 5.27, 7.20*	Sec. 5.27, 7.30	Sec. 10.2.9, 10.2.10, 10.4.6	Sec. 9.2.2, 9.2.10, 9.4.6	Sec. 1.6.2.2, 1.6.2.10, 1.6.4.5	Sec. 10.2.2, 10.2.10, 10.4.5	Sec. 7.27, 9.20
Stability in the moment M_z plane under eccentric compression	Sec. 5.27*	Sec. 5.27	Sec. 10.2.9, 10.2.10, 10.3.1, 10.3.2	Sec. 9.2.9, 9.2.10, 9.3.1, 9.3.2	Sec. 1.6.2.9, 1.6.2.10, 1.6.3.1, 1.6.3.2	Sec. 10.2.9, 10.2.10, 10.3.1, 10.3.2	Sec. 7.27
Stability in the moment M_z plane under eccentric compression (post-buckling behavior)	Sec. 5.27, 7.20*	Sec. 5.27, 7.30	Sec. 10.2.9, 10.2.10, 10.3.1, 10.3.2, 10.4.6	Sec. 9.2.8, 9.2.10, 9.3.1, 9.3.2, 9.4.6	Sec. 1.6.2.8, 1.6.2.10, 1.6.3.1, 1.6.3.2, 1.6.4.5	Sec. 10.2.8, 10.2.10, 10.3.1, 10.3.2, 10.4.5	Sec. 7.27, 9.20
Stability under compression and bending in two planes	Sec. 5.34	Sec. 5.35	Sec. 10.2.9	Sec. 9.2.9	Sec. 1.6.2.9	Sec. 10.2.9	Sec. 7.34
Stability under compression and bending in two planes (post-buckling behavior)	Sec. 5.34, 7.20*	Sec. 5.35, 7.30	Sec. 10.2.9, 10.4.6	Sec. 9.2.9, 9.2.10, 9.4.6	Sec. 1.6.2.9, 1.6.2.10, 1.6.4.5	Sec. 10.2.9, 10.2.10, 10.4.5	Sec. 7.34, 9.20
Stability out of the moment M_y plane under eccentric compression	Sec. 5.30-5.32	Sec. 5.30-5.32	Sec. 10.2.4, 10.2.5, 10.2.8	Sec. 9.2.4, 9.2.5, 9.2.8	Sec. 1.6.2.4, 1.6.2.5, 1.6.2.8	Sec. 10.2.4, 10.2.5, 10.2.8	Sec. 7.30-7.32
Stability out of the moment M_y plane under eccentric compression (post-buckling behavior)	Sec. 5.30-5.32, 7.20*	Sec. 5.30-5.32, 7.30	Sec. 10.2.4, 10.2.5, 10.2.8, 10.4.6	Sec. 9.2.4, 9.2.5, 9.2.8, 9.2.10, 9.4.6	Sec. 1.6.2.4, 1.6.2.5, 1.6.2.8, 1.6.4.5	Sec. 10.2.4, 10.2.5, 10.2.8, 10.4.5	Sec. 7.30-7.32, 9.20
Stability out of the moment M_z plane under eccentric compression (sections of the following types , , , ,, , are not checked)	Sec. 5.27*,5.30-5.32	Sec. 5.27, 5.30-5.32	Sec. 10.2.4, 10.2.5, 10.2.8, 10.3.1, 10.3.2	Sec. 9.2.4, 9.2.5, 9.2.8, 9.3.1, 9.3.2	Sec. 1.6.2.4, 1.6.2.5, 1.6.2.8, 1.6.3.1, 1.6.3.2	Sec. 10.2.4, 10.2.5, 10.2.8, 10.3.1, 10.3.2	Sec. 7.27, 7.30-7.32
Stability out of the moment M_z plane under eccentric compression (post-buckling behavior)	Sec. 5.27, 5.30-5.32, 7.20	Sec. 5.27, 5.30-5.32, 7.30	Sec. 10.2.4,10.2.5,10.2.8, 10.3.1, 10.3.2, 10.4.6	Sec. 9.2.4, 9.2.5, 9.2.8, 9.2.10, 9.3.1, 9.3.2, 9.4.6	Sec. 1.6.2.4, 1.6.2.5, 1.6.2.8, 1.6.3.1, 1.6.3.2, 1.6.4.5	Sec. 10.2.4, 10.2.5, 10.2.8, 10.3.1, 10.3.2, 10.4.5	Sec. 7.27, 7.30-7.32, 9.20
Stability of in-plane bending (sections of the following types , , , , , , , are not checked)	Sec. 5.15	Sec. 5.15	Sec. 9.4.1	Sec. 8.4.1	Sec. 1.5.4.1	Sec. 9.4.1	Sec. 7.15
Lateral-torsional buckling taking into account plastic deformation			Sec. 9.4.6	Sec. 8.4.6	Sec. 1.5.4.6	Sec. 9.4.6	–
Web slenderness based on local stability constraint	Sec. 7.1. 7.2, 7.3, 7.4–7.6, 7.9, 7.10; Sec. 7.14, 7.16, 7.17, 7.18, Table 27*	Sec. 7.1. 7.2, 7.3, 7.4–7.6, 7.9, 7.10; 7.23, 7.26, 7.27, 7.28	Sec. 8.3.2, Table 8; Sec. 8.3.10; Sec. 9.5.1–9.5.9; Sec. 10.4.2, Table 20; Sec. 10.4.3; Sec. 10.4.9	Sec. 7.3.2, Table 9; Sec. 7.3.11; Sec. 8.5.1–8.5.9; Sec. 9.4.2, Table 22; Sec. 9.4.3; Sec. 9.4.9	Sec. 1.4.3.2, Table 1.4.3; Sec. 1.5.5.1–1.5.5.9; Sec. 1.6.4.2, Table 1.6.3; Sec. 1.6.4.5	Sec. 8.3.2, Table 8.3; Sec. 9.5.1–9.5.9; Sec. 10.4.2, Table 10.3; Sec. 10.4.5	Sec. 9.1 –9.7, 9.10,9.11; Sec. 9.15, 9.16, 9.17, 9.18
Flange overhang (flange plate) slenderness based on local stability constraint	Sec. 7.22, 7.23, Table 29, Sec. 7.24, Table 30; Sec. 7.27	Sec. 7.32, 7.33, 7.34, 7.37	Sec. 8.3.7, Table 9; Sec. 8.3.10; Sec. 9.5.14; Sec. 10.4.7, Table 21; Sec. 10.4.9	Sec. 7.3.8, Table 10; Sec. 7.3.11; Sec. 8.5.18; Sec. 9.4.7, Table 23; Sec. 9.4.9	Sec. 1.4.3.7, Table 1.4.4; Sec. 1.5.5.14; Sec. 1.6.4.8, Table 1.6.4; Sec. 1.6.4.7	Sec. 8.3.7, Table 8.4; Sec. 9.5.14; Sec. 10.4.8, Table 10.4; Sec. 10.4.7	Sec. 9.22, 9.23, 9.24, 9.27
Pipe radius to thickness ratio based on local stability constraint	Sec. 8.6	Sec. 8.6	Sec. 12.2.2	Sec. 11.2.2	Sec. 1.10.2.2	Sec. 14.2.2	Sec. 10.6
Local stability of the pipe wall based on closed circular cylindric shell calculation	Sec. 8.5-8.13	Sec. 8.5-8.13	Sec. 12.2.1-12.2.8	Sec. 11.2.1-11.2.9	Sec. 1.10.2.1-1.10.2.9	Sec. 14.2.1-14.2.9	Sec. 10.5-10.13
Beam web height to thickness ratio	Sec. 7.4*	Sec. 7.4	Sec. 9.5.3	Sec. 8.5.3	Sec. 1.5.5.3	Sec. 9.5.3	Sec. 9.5
General stability of a built-up member under axial compression in XoY plane	Sec. 5.3-5.6	Sec. 5.3-5.6	Sec. 8.1.3-8.1.5, 8.2.2	Sec. 7.1.3-7.1.5, 7.2.2	Sec. 1.4.1.3, 1.4.1.5, 1.4.2.2, 1.4.2.5	Sec. 8.1.3, 8.1.5, 8.2.2, 8.2.5	Sec. 7.3-7.6
General stability of a built-up member under axial compression in XoZ plane	Sec. 5.3-5.6	Sec. 5.3-5.6	Sec. 8.1.3-8.1.5, 8.2.2	Sec. 7.1.3-7.1.5, 7.2.2	Sec. 1.4.1.3, 1.4.1.5, 1.4.2.2, 1.4.2.5	Sec. 8.1.3, 8.1.5, 8.2.2, 8.2.5	Sec. 7.3-7.6
Stability out of the moment M_z plane	Sec. 5.30-5.32	Sec. 5.27, 5.30-5.32	Sec. 10.2.4,10.2.5,10.2.8	Sec. 9.2.4,9.2.5,9.2.8	Sec. 1.6.2.4, 1.6.2.5, 1.6.2.8	Sec. 10.2.4, 10.2.5, 10.2.8	Sec. 7.27*, 7.30-7.32
Resistance of a batten to bending	Sec. 5.8, 5.9, 5.36	Sec. 5.8, 5.9, 5.38	Sec. 8.2.7, 8.2.8, 10.3.7	Sec. 7.2.7, 7.2.8, 9.3.7	Sec. 1.4.2.7, 1.4.2.8, 1.6.3.7	Sec. 8.2.7, 8.2.8, 10.3.7	Sec. 7.8, 7.9, 7.36
Strength of chord under bending moment M_y	Sec. 5.12	Sec. 5.12	Sec. 9.2.1	Sec. 8.2.1	Sec. 1.5.2.1	Sec. 9.2.1	Sec. 7.12
Strength of chord under bending moment M_z	Sec. 5.12	Sec. 5.12	Sec. 9.2.1	Sec. 8.2.1	Sec. 1.5.2.1	Sec. 9.2.1	Sec. 7.12
Strength of chord under lateral force Q_y	Sec. 5.12, 5.18*	Sec. 5.12, 5.18*	Sec. 9.2.1, 9.2.3	Sec. 8.2.1, 8.2.3	Sec. 1.5.2.1, 1.5.2.3	Sec. 9.2.1, 9.2.3	Sec. 7.12, 7.18
Strength of chord under lateral force Q_z	Sec. 5.12, 5.18*	Sec. 5.12, 5.18	Sec. 9.2.1, 9.2.3	Sec. 8.2.1, 8.2.3	Sec. 1.5.2.1, 1.5.2.3	Sec. 9.2.1, 9.2.3	Sec. 7.12, 7.18
Strength of chord under combined action of longitudinal force and bending moments	Sec. 5.24, 5.25, 5.33	Sec. 5.24, 5.25, 5.33	Sec. 10.1.1, 10.3.3	Sec. 9.1.1, 9.3.3	Sec. 1.6.1.1, 1.6.3.3	Sec. 10.1.1, 10.3.3	Sec. 7.24, 7.25, 7.33
Strength of chord under combined action of longitudinal force and bending moments, allowing for plasticity	Sec. 5.24, 5.25, 5.33	Sec. 5.24, 5.25, 5.33	Sec. 10.1.1, 10.3.3	Sec. 9.1.1, 9.3.3	Sec. 1.6.1.1, 1.6.3.3	Sec. 10.1.1, 10.3.3	Sec. 7.24, 7.25, 7.33
Strength of chord under combined action of longitudinal force and bending moments, no plasticity	Sec. 5.24, 5.25, 5.33	Sec. 5.24, 5.25, 5.33	Sec. 10.1.1, 10.3.3	Sec. 9.1.1, 9.3.3	Sec. 1.6.1.1, 1.6.3.3	Sec. 10.1.1, 10.3.3	Sec. 7.24, 7.25, 7.33
Stability of chord under compression in XoY plane	Sec. 5.3, 5.6	Sec. 5.3, 5.6	Sec. 8.1.3, 8.2.3-8.2.5	Sec. 7.1.3, 7.2.3-7.2.5	Sec. 1.4.1.3, 1.4.2.3, 1.4.2.4	Sec. 8.1.3, 8.2.3, 8.2.4	Sec. 7.3, 7.6
Stability of chord under compression in XoY plane (post-buckling behavior)	Sec. 5.3, 5.6, 7.20*	Sec. 5.3, 5.6, 7.30	Sec. 8.1.3, 8.2.3-8.2.5, 8.3.5	Sec. 7.1.3, 7.2.3-7.2.5, 7.3.6	Sec. 1.4.1.3, 1.4.2.3, 1.4.2.4, 1.4.3.5	Sec. 8.1.3, 8.2.3, 8.2.4, 8.3.5	Sec. 7.3, 7.6, 9.20
Stability of chord under compression in XoZ plane	Sec. 5.3, 5.6	Sec. 5.3, 5.6	Sec. 8.1.3, 8.2.3-8.2.5	Sec. 7.1.3, 7.2.3-7.2.5	Sec. 1.4.1.3, 1.4.2.3, 1.4.2.4	Sec. 8.1.3, 8.2.3, 8.2.4	Sec. 7.3, 7.6
Stability of chord under compression in XoZ plane (post-buckling behavior)	Sec. 5.3, 5.6, 7.20*	Sec. 5.3, 5.6, 7.30	Sec. 8.1.3, 8.2.3-8.2.5, 8.3.5	Sec. 7.1.3, 7.2.3-7.2.5, 7.3.6	Sec. 1.4.1.3, 1.4.2.3, 1.4.2.4, 1.4.3.5	Sec. 8.1.3, 8.2.3, 8.2.4, 8.3.5	Sec. 7.3, 7.6, 9.20
Stability of chord in the moment M_y plane under eccentric compression	Sec. 5.27*, 5.33, 5.35	Sec. 5.27*, 5.33, 5.35	Sec. 10.2.9, 10.3.3, 10.3.4, 10.3.6	Sec. 9.2.9, 9.3.3, 9.3.4, 9.3.6	Sec. 1.6.2.9, 1.6.3.3-1.6.3.5	Sec. 10.2.9, 10.3.3-10.3.5	Sec. 7.27, 7.33, 7.35
Stability of chord in the moment M_y plane under eccentric compression (post-buckling behavior)	Sec. 5.27, 5.33, 5.35, 7.20	Sec. 5.27, 5.33, 5.37, 7.30	Sec. 10.2.9, 10.2.10, 10.3.3, 10.3.4, 10.3.6, 10.4.6	Sec. 9.2.2, 9.2.10, 9.3.3, 9.3.4, 9.3.6, 9.4.6	Sec. 1.6.2.2, 1.6.2.10, 1.6.3.3-1.6.3.5, 1.6.4.5	Sec. 10.2.2, 10.2.10, 10.3.3-10.3.5, 10.4.5	Sec. 7.27, 7.33, 7.35, 9.20
Stability of chord in the moment M_z plane under eccentric compression	Sec. 5.27*, 5.33, 5.35	Sec. 5.27, 5.33, 5.37	Sec. 10.2.9, 10.3.3, 10.3.4, 10.3.6	Sec. 9.2.9, 9.3.1, 9.3.3, 9.3.4, 9.3.6	Sec. 1.6.2.9, 1.6.3.3-1.6.3.5	Sec. 10.2.9, 10.3.3-10.3.5	Sec. 7.27, 7.33, 7.35
Stability of chord in the moment M_z plane under eccentric compression (post-buckling behavior)	Sec. 5.27, 5.33, 5.35, 7.20	Sec. 5.27, 5.33, 5.37, 7.30	Sec. 10.2.9, 10.2.10, 10.3.2-10.3.4, 10.3.6, 10.4.6	Sec. 9.2.8, 9.2.10, 9.3.1-9.3.2, 9.3.4, 9.3.6, 9.4.6	Sec. 1.6.2.8, 1.6.2.10, 1.6.3.2-1.6.3.5, 1.6.4.5	Sec. 10.2.8, 10.2.10, 10.3.2-10.3.5, 10.4.5	Sec. 7.27, 7.33, 7.35, 9.20
Bending of chord in two principal planes	Sec. 5.24,5.25	Sec. 5.24, 5.25	Sec. 10.1.1	Sec. 9.1.1	Sec. 1.6.1.1	Sec. 10.1.1	Sec. 7.24, 7.25
Stability of chord out of the moment My plane under eccentric compression	Sec. 5.27*, 5.30-5.33, 5.35	Sec. 5.27, 5.30-5.33, 5.37	Sec. 10.2.4, 10.2.5, 10.2.8, 10.3.3, 10.3.4, 10.3.6	Sec. 9.2.4, 9.2.5, 9.2.8, 9.3.1, 9.3.3, 9.3.4, 9.3.6	Sec. 1.6.2.4, 1.6.2.5, 1.6.2.8, 1.6.3.3-1.6.3.5	Sec. 10.2.4, 10.2.5, 10.2.8, 10.3.3-10.3.5	Sec. 7.27, 7.30-7.33, 7.35
Stability of chord out of the moment My plane under eccentric compression (post-buckling behavior)	Sec. 5.27, 5.30-5.33, 5.35, 7.20	Sec. 5.27, 5.30-5.33, 5.37, 7.30	Sec. 10.2.4, 10.2.5, 10.2.8, 10.3.3, 10.3.4, 10.3.6, 10.4.6	Sec. 9.2.4, 9.2.5, 9.2.8, 9.2.10, 9.3.1, 9.3.3, 9.3.4, 9.3.6, 9.4.6	Sec. 1.6.2.4, 1.6.2.5, 1.6.2.8, 1.6.3.3-1.6.3.5, 1.6.4.5	Sec. 10.2.4, 10.2.5, 10.2.8, 10.3.3-10.3.5, 10.4.5	Sec. 7.27, 7.30-7.33, 7.35, 9.20
Stability of chord out of the moment Mz plane under eccentric compression	Sec. 5.27*, 5.30-5.33, 5.35	Sec. 5.27, 5.30-5.33, 5.37	Sec. 10.2.4, 10.2.5, 10.2.8, 10.3.3, 10.3.4, 10.3.6	Sec. 9.2.4, 9.2.5, 9.2.8, 9.3.1, 9.3.3, 9.3.4, 9.3.6	Sec. 1.6.2.4, 1.6.2.5, 1.6.2.8, 1.6.3.3-1.6.3.5	Sec. 10.2.4, 10.2.5, 10.2.8, 10.3.3-10.3.5	Sec. 7.27, 7.30-7.33, 7.35
Stability of chord out of the moment Mz plane under eccentric compression (post-buckling behavior)	Sec. 5.27, 5.30-5.33, 5.35, 7.20	Sec. 5.27, 5.30-5.33, 5.37, 7.30	Sec. 10.2.4, 10.2.5, 10.2.8, 10.3.3, 10.3.4, 10.3.6, 10.4.6	Sec. 9.2.4, 9.2.5, 9.2.8, 9.2.10, 9.3.1, 9.3.3, 9.3.4, 9.3.6, 9.4.6	Sec. 1.6.2.4, 1.6.2.5, 1.6.2.8, 1.6.3.3-1.6.3.5, 1.6.4.5	Sec. 10.2.4, 10.2.5, 10.2.8, 10.3.3-10.3.5, 10.4.5	Sec. 7.27, 7.30-7.33, 7.35, 9.20
Strength of chord under tension	Sec. 5.1, 5.6	Sec. 5.1, 5.6	Sec. 8.1.1, 8.2.1	Sec. 7.1.1, 7.2.1	Sec. 1.4.1.3, 1.4.2.1	Sec. 8.1.3, 8.2.1	Sec. 7.1, 7.6
Stability of chord under compression	Sec. 5.3, 5.6	Sec. 5.3, 5.6	Sec. 8.1.3, 8.2.3-8.2.5	Sec. 7.1.3, 7.2.3-7.2.5	Sec. 1.4.1.3, 1.4.2.3-1.4.2.4	Sec. 8.1.3, 8.2.3-8.2.4	Sec. 7.3, 7.6
Stability of chord under compression (post-buckling behavior)	Sec. 5.3, 5.6, 7.20*	Sec. 5.3, 5.6, 7.30	Sec. 8.1.3, 8.2.3-8.2.5, 8.3.5	Sec. 7.1.3, 7.2.3-7.2.5, 7.3.6	Sec. 1.4.1.3, 1.4.2.3-1.4.2.4, 1.4.3.5	Sec. 8.1.3, 8.2.3-8.2.4, 8.3.5	Sec. 7.3, 7.6, 9.20
Excessive deformations of the tension chord fiber	Sec. 5.28	Sec. 5.28	Sec. 10.1.3	Sec. 9.1.3	Sec. 1.6.1.3	Sec. 10.1.3	Sec. 7.28
Stability of in-plane bending of the chord	Sec. 5.15	Sec. 5.15	Sec. 9.4.1	Sec. 8.4.1	Sec. 1.5.4.1	Sec. 9.4.1	Sec. 7.15
Chord web slenderness based on local stability constraint	Sec. 7.1. 7.2, 7.3, 7.4–7.6, 7.9,7.10; Sec. 7.14, 7.16, 7.17, 7.18, Table 27*	Sec. 7.1. 7.2, 7.3, 7.4–7.6, 7.9,7.10; 7.23, 7.26, 7.27, 7.28	Sec. 8.3.2, Table 8; Sec. 8.3.10; Sec. 9.5.1–9.5.9; Sec. 10.4.2, Table 20; Sec. 10.4.3; Sec. 10.4.9	Sec. 7.3.2, Table 9; Sec. 7.3.11; Sec. 8.5.1–8.5.9; Sec. 9.4.2, Table 22; Sec. 9.4.3; Sec. 9.4.9	Sec. 1.4.3.2, Table 1.4.3; Sec. 1.5.5.1–1.5.5.9; Sec. 1.6.4.2, Table 1.6.3; Sec. 1.6.4.5	Sec. 8.3.2, Table 8.3; Sec. 9.5.1–9.5.9; Sec. 10.4.2, Table 10.3; Sec. 10.4.5	Sec. 9.1 – 9.7, 9.10, 9.11; Sec. 9.15, 9.16, 9.17, 9.18
Chord flange slenderness based on local stability constraint	Sec. 7.22, 7.23, Table 29, Sec. 7.24, Table 30; Sec. 7.27	Sec. 7.32, 7.33, 7.34, 7.37	Sec. 8.3.7, Table 9; Sec. 8.3.10; Sec. 9.5.14; Sec. 10.4.7, Table 21; Sec. 10.4.9	Sec. 7.3.8, Table 10; Sec. 7.3.11; Sec. 8.5.18; Sec. 9.4.7, Table 23; Sec. 9.4.9	Sec. 1.4.3.7, Table 1.4.4; Sec. 1.5.5.14; Sec. 1.6.4.8, Table 1.6.4; Sec. 1.6.4.7	Sec. 8.3.7, Table 8.4; Sec. 9.5.14; Sec. 10.4.8, Table 10.4; Sec. 10.4.7	Sec. 9.22, 9.23, 9.24, 9.27
Strength of lattice posts	Sec. 5.8*, 5.10	Sec. 5.8, 5.10	Sec. 8.2.7, 8.2.9	Sec. 7.2.7, 7.2.9	Sec. 1.4.2.7, 1.4.2.9	Sec. 8.2.7, 8.2.9	Sec. 7.8, 7.10
Strength of lattice struts	Sec. 5.8*, 5.10	Sec. 5.8, 5.10	Sec. 8.2.7, 8.2.9	Sec. 7.2.7, 7.2.9	Sec. 1.4.2.7, 1.4.2.9	Sec. 8.2.7, 8.2.9	Sec. 7.8, 7.10
Stability of lattice posts under compression	Sec. 5.8*, 5.10, 5.3	Sec. 5.8, 5.10, 5.3	Sec. 8.2.7, 8.2.9, 8.1.3	Sec. 7.2.7, 7.2.9, 7.1.3	Sec. 1.4.2.7, 1.4.2.9, 1.4.1.3	Sec. 8.2.7, 8.2.9, 8.1.3	Sec. 7.3, 7.8, 7.10
Stability of lattice struts under compression	Sec. 5.8*, 5.10, 5.3	Sec. 5.8, 5.10, 5.3	Sec. 8.2.7, 8.2.9, 8.1.3	Sec. 7.2.7, 7.2.9, 7.1.3	Sec. 1.4.2.7, 1.4.2.9, 1.4.1.3	Sec. 8.2.7, 8.2.9, 8.1.3	Sec. 7.3, 7.8, 7.10
Limit slenderness in XoY plane	Sec. 6.15, 6.16	Sec. 6.14, 6.15	Sec. 11.4.1	Sec. 10.4.1	Sec. 1.9.4.1	Sec. 13.4.1	Sec. 8.18
Limit slenderness in XoZ plane	Sec. 6.15, 6.16	Sec. 6.14, 6.15	Sec. 11.4.1	Sec. 10.4.1	Sec. 1.9.4.1	Sec. 13.4.1	Sec. 8.18

Flexibility checks use the values specified in the Limit Slenderness mode.

Only the cross-section of the element is checked.

The following checks are not performed:

of the weakened sections with holes for bolts;
of the analysis of the battens and lattices, except for the Columns mode;
of the local stress in the beam web from the concentrated force, except for the Beams and Local Stability modes;
of local web buckling for I-sections and box cross-sections taking into account longitudinal stiffeners;
of the strength of continuous and clamped beams allowing for the redistribution of forces in the plastic stage.

Peculiarities of the implementation

SNiP does not consider the problem of stability for a bar under tension and bending, but it would be unwise not to check it for stability at all, because even a relatively small tension can cause the buckling of the bar (in an elastic bar this would occur when some fibers were in compression, while in an elastoplastic bar this boundary would be harder to locate). Since design codes do not define a boundary for such a "relatively small tension", we assumed it equal to zero, hence a simply bent bar is considered.
Since design codes do not provide a general recommendation for checking the stability of in-plane bending for a structure with arbitrary restraints and arbitrary positioning of the loads, a check based on an assumption that there are no intermediate bracings of the member is implemented, i.e. the effective length of the member in the respective formula is taken as its geometric length.
When determining the relative eccentricity of eccentrically loaded bars the design codes recommend taking the design moment as the moment in the section, which is located in a particular area of the bar. This area is determined depending on the boundary conditions of the bar, on which the program has no information. Therefore, the value of the moment maximal along the length of the element is used.
Technically the codes do not require to check the axial compression stability of structures under eccentric compression (for example, under the action of N,M_y,M_z). However, without checking that the axial compression stability is ensured, other checks may become meaningless. For example, the value of the limit slenderness of the 180-60α type can become negative (the value of a coincides with the axial compression stability factor). Therefore, the axial compression stability factors are always calculated.
The recommendations of the codes for determining the section shape factor η for a welded unequal I-beam are provided only for the case when the ratio of the area of the smaller flange to the area of the larger flange is 0.5. If this ratio exceeds 0.5, the software performs a linear interpolation between the values of η calculated for an equal I-beam and the values of η calculated for an unequal I-beam with the ratio of the area of the smaller flange to the area of the larger flange equal to 0,5. This approach is recommended in Modification No.1 to DBN B.2.6-198:2014.

There is no separate strength analysis of members bending in two principal planes. This check is included in the strength check under the combined action of the longitudinal force and bending moments as a particular case at N = 0.

The dialog box of this mode contains six tabs: Materials, Section, Forces, Effective Length in the XoY Plane, Effective Length in the XoZ Plane, Interaction Curves. The first five tabs are used to enter the initial data, and the sixth one to analyze the results of the calculation.

The Materials tab contains buttons for accessing the reference modes Steel — $image\kristall_74.jpg$ , Service Factor — $image\kristall_73.jpg$ , and Limit Slenderness — $image\kristall_70.jpg$ . Properties selected in the reference modes are transferred to the respective fields, and can be modified only by accessing the same modes again.

Importance factors — $image\kristall_73.jpg$ — are specified in the Material tab of the Application Settings dialog box. This tab is also used in cases when the properties of steel or values of the factors have to be assigned values different from those defined by the design codes.

For members carrying the longitudinal force and the bending moment, design standards for steel structures suggest two possible strength checks:

taking into account the possible elastoplastic behavior;
in the absence of the inelastic behavior.

The possibility of the elastoplastic behavior is limited by a number of conditions, such as the absence of the direct action of dynamic loads.

In the case where there is a direct action of dynamic loads, as well as in cases when the user for some other reasons does not want to go beyond the elastic behavior, he can use the Inelasticity is not allowed checkbox provided on this tab.

The Web instability is forbidden checkbox is used to perform the check of the section taking into account its post-buckling behavior (after the local buckling of the web). The checked checkbox enables to reject the post-buckling behavior of the section if the check indicates local buckling of the web.

The Section tab contains eighteen buttons clicking which enables you to set the desired cross-section type. The selected section can be saved in the Custom Sections catalogue the access to which is provided by the button $image\kristall_71.jpg$ .

The length between restraints out of the bending plane has to be specified (this value will be used in the analysis of stability of in-plane bending).

If the transverse stiffeners can be installed for the given cross-sections, you can use the Stiffeners checkbox, thus indicating that the stiffeners are installed, and specify their spacing. If this spacing is greater than the length of the element, the local stability analysis of the web is performed as for a web without stiffeners. If the web has such a slenderness that the element can be classified as an element with a flexible web, the application outputs the Ratio between height and width of the web factor with a value greater than 1,0. The calculation of elements with a flexible web is not implemented in the program due to the extremely limited scope of the method for calculating such structures (only for continuous beams bearing the static load).

This mode enables to perform the checks taking into account the corrosion. To do it, check the respective checkbox, specify the corrosion layer thickness or use the button $image\calc.png$ to calculate the corrosion layer thickness. In the Corrosion layer thickness dialog box you should specify the data on the properties of corrosive medium, conditions of placement, its working life, and the direction of the axes of inertia. As a result, a prediction of corrosion will be generated. The analysis is based on the assumption that the thickness of the corrosion layer is the same along the whole perimeter of the section.

The button $image\ebx_1370862028.jpg$ can be used to access an archive of custom sections created by Section Builder, Consul, and Tonus.

It should be noted that any section generated by Section Builder is treated as a custom section (one different from a standard section). This rule also applies to the cases when the created section has a "standard" shape (for example, it may be just a rolled or welded I-beam, channel etc.). The application provides a lot of other capabilities for creating standard shapes.

Since SNiP, SP, and DBN do not provide any recommendations for the determination of some parameters for the analysis of custom sections (section shape factor η, coefficients α and β according to Table 10 of SNiP, etc.), the analysis uses the most unfavorable values of these parameters, and the check for the stability of in-plane bending is not performed at all due to the assumption that the possibility for this mode of buckling to occur is excluded by the appropriate restraints. Moreover, different results will be obtained by the analysis of the section behavior under shear forces. The matter is that calculation of the tangential stresses according to the design codes is based on the assumption that the shear force is resisted only by those parts of the section which are “oriented” along the force direction. For example, the shear force Q_z is transferred only to the web of an I-beam, only the flanges of an I-beam resist the shear force Q_y simultaneously. If the section is a custom one, there are no concepts of web and flange, and the application assumes that the shear is resisted by the whole section.

This is the reason for the difference between the results of the analysis of two identical sections: one section created with "standard tools" and the other – by Section Builder.

The Forces tab is used to specify forces acting in the cross-section of the member. It displays a cross-section with the principal axes of inertia and the positive directions of forces. The tab contains a table for specifying the forces acting in the section from one or more load cases. The number of rows in the table corresponds to the number of the load cases and can be increased by clicking the Add button. To delete the selected rows, click the Delete button.

The Seismic checkbox can be checked for some loadings. In this case, requirements of the respective code (selected in the main window) on the use of the additional service factor at the construction in seismic regions will be automatically taken into account. Moreover, a special table will appear in this dialog box where you can specify the coefficients allowing for seismic action at the strength and stability analysis. If zero values are specified, the values are taken in accordance with the respective seismic codes by default. Having specified, for example, these two coefficients equal to 0.9, you can take into account the standard requirements for the calculation of steel structures operating in unheated rooms or in the open air at the design temperature below minus 40 ° C.

If the calculation is performed according to SP 16.13330, then the Special checkbox can be checked for a certain loading (a special non-seismic loading). In this case you will be able to specify a service factor in accordance with Annex B of SP 296.1325800.2017 in the special table (moreover, the importance factor γ_n = 1.0 in accordance with Sec. 5.5 of SP 296.1325800.2017 will be used for such loadings). Furthermore, an additional service factor which reduces the design strength and is considered in Sec. 5.11 and Annex C of SP 296.1325800.2017 can be taken into account.

Note that there is a discrepancy between SP 296.1325800 and SP 385.1325800. SP 296.1325800 introduces a service factor for ductile steels equal to 1.1, but at the same time it speaks of the need for calculations based on the requirements for calculations for progressive collapse (SP 385.1325800). Change No. 1 to SP 385.1325800 provides a service factor of 1.2. The program uses a value of 1.2.

The table can be also filled by importing the data from SCAD which describe the design combinations of forces (DCF). A file with the .rsu extension is created in the Element Information mode of the SCAD software and then can be imported into Kristall by clicking the button $image\ebx_1647931852.jpg$ above the table. Note that when using sections created by Section Builder the forces must be specified in the principal axes, U, V. M_y should be assigned the value of M_u (a moment with respect to the axis of the maximum moment of inertia), M_z should be replaced by the value of M_v, and so on.

To change the plane of loading, use the respective button. This will transfer the values of M_y and Q_y to the respective columns of the table for M_z and Q_z, and vice versa.

The Effective Length in the XoY (XoZ) Plane tabs are the exact replicas of the Effective Lengths tab for the case of Separate columns and posts from the Effective Lengths mode, and they suggest 25 possible conditions of end support in the respective planes of loading for a compressed bar member, which differ from one another in combinations of the boundary conditions (free end, hinge, elastic support, elastic clamping, clamped).

Unlike the Effective Lengths mode, this dialog has the Effective length factor specified by user button, . Clicking this button will enable you to enter any desired values for the effective length factor and confirm your choice by clicking the Apply button. In all other cases this field is inaccessible.

Once you have entered the initial data, you can click the Calculate button, and the K_max field located at the bottom of the dialog will display the maximum (i.e. the most dangerous) value of the checked utilization factors of restrictions and the type of the check (strength, stability, local stability etc.) in which this maximum took place. You can browse interactively the values of all the other utilization factors of restrictions. To do it, use the Factors button which becomes available once the analysis is completed. The Factors Diagram dialog box displays the respective factors numerically and graphically.

Moreover, the curves enclosing an area of the section load-bearing capacity under various pairs of forces which can arise in the considered section are plotted in the Interaction Curves tab.

Click the Show button to generate such a curve. A drop-down list serves to select a pair of forces, and clicking the button $image\show_hide_grid.png$ displays a grid in the display field. The curves surround the coordinate origin by a closed line inside which there are points with conditionally acceptable pairs of the considered forces. A pair of forces is deemed acceptable when K_max ≤ 1. All other forces are taken as values specified in the Fixed values group.

Using your mouse pointer, you can explore the area of the forces variation shown in the graph. Every position of the pointer corresponds to a pair of numerical values of the acting forces; their values are displayed in the respective fields.

Since the slenderness factors do not depend on the forces, they are NOT calculated when plotting the interaction curves.

The dialog also displays the maximum value of the utilization factor of restrictions that corresponds to these forces and the type of check in which it takes place. When the pointer is placed over a point where K_max > 1, a warning sign is displayed $image\kristall_68.jpg$ .

Clicking the right mouse button will display the list of performed checks and values of the factors for the set of forces corresponding to the position of the pointer in the plot area of the interaction curve.

The dialog box also contains three buttons: , which enable to perform the following operations:

— if the forces are specified, clicking this button will draw the points the coordinates of which in the area of the load-bearing capacity correspond to these forces;

— drawing a convex hull of the points specified above, i.e. an entire set of points which may result from a linear combination of specified forces, including their incomplete values;

— saving the forces that can lead to K_max=1 in a text file (this file can be imported into other programs for further analysis).