Slendness: k. L / r <= 300
Gross area
Summing the products of the thickness and the gross width of each
element (flange, web, leg, plate), as measured normal to the axis of the
member.
Effective Net Area
The effective net area, A_{ne}, shall be determined by
summing the critical net areas, A_{n}, of each segment along a
potential path of minimum resistance:
For a segment normal to the force (ie, in direct tension)
A_{n} = w_{n}.t
For a segment parallel to the force (ie, in shear)
A_{n} = 0.6 L_{n}.t
For a segment inclined to the force
A_{n} = w_{n}.t + s^{2}.t /
(4g)
For w_{n} and L_{n}, the width of bolt holes shall
be taken as 2mm larger than the specified hole diameter.
Effective Net Area Reduction-Shear Lag
When bolts transmit load to some but not all of the cross-sectional
elements and only when the critical net area includes the net area of
unconnected elements, the reduced effective net area shall be taken as follows:
Bolts:
1). for WWF, W,or S shapes with flange widths not less than 2/3 of
the depth, and for structural tees cut from these shapes, when only the flanges
are connected with three or more transverse lines of bolts:
A_{ne} = 0.90 A_{n}
2). for angles connected by only one leg with
four or more transverse lines of fasteners,
A_{ne} = 0.80 A_{n}
fewer than four transverse lines of fasteners,
A_{ne} = 0.60 A_{n}
3). for all other structural shapes connected with
Three or more transverse lines of fasteners: A_{ne}
= 0.85 A_{n}
with two transverse lines of fasteners: A_{ne} =
0.75 A_{n}
Welds:
A_{ne} = A_{n1} + A_{n2} + A_{n3}
1). Elements connected by transverse welds, A_{n1} = w.t
2). Elements connected by longitudinal welds along two parallel
edges, A_{n2}
when L >= 2w, A_{n2} = 1.0 w.t
when 2w > L >= w, A_{n2} = 0.5 w.t + 0.25
L.t
when L < w, A_{n2} = 0.75 w.t
L = average length of welds on the two edge
w = plate width (distance between welds)
3). Elements connected by a single line of weld,
When L >= w
A_{n3} = [ 1 - x_{1} / L].w.t
When L < w
A_{n3} = 0.5 L.t
x_{1} = eccentricity of the weld with respect
to centroid of the element
L = length of connection in the direction of the
loading
Axial Tension:
T_{r} = f. A_{g}.F_{y}
T_{r} = f_{u}.
A_{ne}.F_{u}
Tension and Shear Block Failure:
The factored resistance for a potential failure involving the
simultaneous development of tensile and shearcomponent areas shall be taken as
T_{r} = f_{u}.[U_{t}.
A_{n}. F_{u} + 0.6 A_{gv}.(F_{y} + F_{u})/2]
Where
A_{n} = the net area in tension
A_{gv} = the gross area in shear
f_{u} = 0.75
U_{t} = an efficiency factor, = 1 for
symmetrical blocks or failure patterns and concentric loading
Reference: CSA S16-09, Cl.12, Cl. 13.2, Cl. 13.11