D5.C.5.3 Members Subject to Shear
The cross section capacity of a member subject to shear is checked as per Cl. 6.2.6 of the code. The condition to be satisfied is:
where= | ||
= |
Shear Buckling
For sections that are susceptible to shear buckling, the program will perform the shear buckling checks as given in Section 5 of EN 1993-1-5. The shear buckling checks will be done only for I –Sections and Channel sections. Shear stresses induced from torsional loads are taken into account while performing torsion checks.
The susceptibility of a section to shear buckling will be based on the criteria given in Cl 5.1(2) of EN 1993-1-5 as is as given as follows:
-
For unstiffened webs, if , the section must be checked for shear buckling.
The design resistance is calculated as:
where- hw
= - distance between flanges of an I Section (i.e., depth - 2x flange thickness)
- t
= - thickness of the web
- ε
= - √(235/fy), where fy is the yield stress
- η
= - 1.2 for steel grades up to and including S 460 and
= 1.0 for other steel grades
- kτ
= - as defined in sections below
- χw
= - the web contribution factor obtained from Table 5.1 of the EC3 code and is evaluated per the following table:
Table 1. Evaluate of χw Slenderness Parameter Rigid End Post Non-rigid End Post η η = -
For stiffened webs, if , the section must be checked for shear buckling.
The design resistances considers tension field action of the web and flanges acting as struts in a truss model. This is calculated as:
Where:
where- Vbf,Rd
= - the flange resistance per Cl.5.4 for a flange not completely utilized by bending moment
- Vbf,Rd
= - bf
= - the width of the flange which provides the least axial resistance, not to be taken greater than 15εtf on each side of the web
- tf
= - the thickness of the flange which provides the least axial resistance
- Mf,Rd
= - Mf,k/γM0 , the moment of resistance of the cross section consisting of the effective area of the flanges only. For a typical I Section or PFD, this is evaluated as b·tf·hw . When an axial load, NEd, is present, the value of Mf,Rd is reduced by multiplying by the following factor:
- Af1 ,Af2
= - the areas of the top and bottom flanges, respectively
- c
= - a
= - transverse stiffener spacing. The equation of c is likewise used to solve for a sufficient stiffener spacing in the case of demand from loads exceeding the calculated capacity for a specified stiffener spacing
The following equation must be satisfied for the web shear buckling check to pass:
where= |
If the stiffener spacing has not been provided (using the STIFF parameter), then the program assumes that the member end forms a non-rigid post (case c) and proceeds to evaluate the minimum stiffener spacing required.