钢结构截面强度验算

Verification of steel cross-sections is carried out for two cases of load:

1. for the maximum value of bending moment and the corresponding shear force (M_max + Q)
2. for the maximum shear force and the corresponding bending moment (Q_max + M)

In both cases, the load enters to the assessment with an influence of normal force, which is defined separately. Its value is identical for both of load cases. Internal forces are, prior to analysis, pre-multiplied by the reduction coefficient of bearing capacity. This coefficient represents the degree of uncertainty of the determination of theoretical values of internal forces and as thus introduces into the analysis with such values certain reliability. The value of this coefficient is determined solely by the user.

The "Sheeting Check" program exploits following types of analyses for steel cross section check:

• Verification according to EN 1993-1-1 (EC 3)
• Verification according to CSN 73 1401
• Verification according to safety factor
• Verification according to limit states
• Verification according to GB 50017-2003

Each cross-section is checked for free types of load:

1. Check for bending moment and normal force

The analysis checks the normal stress σ developed at the edge of cross-section given by:

2. Check for shear

The analysis checks the shear stress τ at the cross-section center of gravity written as:

3. Check for state of plane stress for the combination of stresses σ₁ and τ₁ at the point of critical load

Equivalent stress for plane stress conditions is defined as:

All verifications are carried out assuming elastic response of the material, plasticity is not taken into consideration.

Verification of steel I-profiles

Internal forces provide by the "Sheeting Check" program are considered per 1 m run of the structure width. Therefore, the units of shear force Q are kN/m and of bending moments M are kNm/m. For dimensioning of individual I-profiles these forces are, prior to verification analysis, automatically multiplied by their spacing a [m] to get their values at the cross-section center of gravity, i.e. shear force Q in kN and bending moment M in kNm. The normal stress σ is checked at the outer face of flange. The shear stress τ is checked at the center of gravity, thus at the center of web height. The equivalent stress σ_k is checked in the web at the flange-web connection (cut 1).

Verification of pile sheet wall

The verification analysis is carried out for a wall section of a unit length. All cross-sectional parameters are therefore determined not for individual sheet piles, but for a wall section of a unit length. The normal stress σ is checked at the outer face of back of sheet piles. The shear stress τ is checked at the web center of gravity, thus for sheet piles of U shape at the location of locks and for sheet piles of Z shape at the center of inclined sheet pile webs. The equivalent stress σ_k is checked in the sheet pile web at the location of connection of back of sheet piles (cut 1).