Gross area
  A_g = Gross area of cross section.

Net Area
  Net area A_n of a member is the sum of the products of the thickness and the net width of each element.
    For a part in any diagonal or zigzag line, the additional quantity is:   s².t / (4g)

  s = longitudinal center-to-center spacing (pitch) of any two consecutive holes.
  g = transverse center-to-center spacing (gage) between fastner gage lines.

Effective Net Area, Reduction-Shear Lag Coefficient (U)

  Bolts:
    A_e = A_n . U

  For angle members having two and more bolts in the line of force:    U = 1 - 1.2 x/L < 0.9,   but >= 0.4

  For channel members having two and more bolts in the line of force:    U = 1 - 0.36 x/L < 0.9,   but >= 0.5

  x - distance from shear plane to centroid of the cross section
  L - length of the connection in the direction of loading

  Welds:
  (a) When the tension load is transmitted only by longitudinal welds or by longitudinal welds in combination with transverse welds:
    A_e = A_g . U

  U - reduction coefficient = 1 - x/L <= 0.9
  A_g - gross area of member

  (b) When the tension load is transmitted only by transverse welds:
    A_e = A . U

  U = 1.0
  A - area of directly connected elements

  (c) Otherwise:

  for angle members:    U = 1 - 1.2 X/L < 0.9 but U >= 0.4

  for channel members:    U = 1 - 0.36 X/L < 0.9 but U >= 0.5

   x - distance from shear plane to centroid of cross section
   L - length of longitudinal weld

Design Strength for Tension Members:

  Yielding in the gross section: (Eq. C2-1)
     fT_n = f.F_y.A_g= 0.90 F_y.A_g   LRFD

     T_a = F_y.A_g / O_t = F_y.A_g/1.67  ASD

  Fracture in the net section: (Eq. C2-2)
     fT_n = f.F_u.A_e= 0.75 F_u.A_e  LRFD

     T_a = F_u.A_e / O_t = F_u.A_e/2.0  ASD

Design Rupture Strength:

  Shear Rupture Strength: (Eq. E5.1-1)
     fV_n = f(0.6).F_u.A_nv= 0.75 (0.6) F_u.A_nv  LRFD

     V_a = (0.6).F_u.A_nv / O = (0.6) F_u.A_nv/2.0   ASD

  Tension Rupture Strength for Welded Connection: (Eq. E2.7-1)
     fP_n = f.F_u.A_e= 0.6 F_u.A_e  LRFD

     P_a = F_u.A_e / O = F_u.A_e/2.5  ASD

  Tension Rupture Strength for Bolted Connection: (Appendix A, E3.2)

  a) For flat sheet connections not having staggered hole patterns:

    1)   for washers are provided under both the bolt head and the nut
    fP_n = f. F_t. A_n   LRFD
    P_a = F_t. A_n / O   ASD
     for single bolt, F_t =(0.1 + 3d/s)F_u <= F_u
     for multiple bolts, F_t = F_u
      f = 0.65 for double shear, 0.55 for single shear

       O = 2.0 for double shear, 2.22 for single shear

    2)   for washers are NOT provided under both the bolt head and the nut

    fP_n = f. F_t. A_n   LRFD
    P_a = F_t. A_n / O   ASD
     for single bolt, F_t = (2.5 d/s)F_u <= F_u
     for multiple bolts, F_t = F_u
      f = 0.65

       O = 2.0

  b) For flat sheet connections having staggered hole patterns:

     fP_n = f. F_u.A_n
      f = 0.65   LRFD

     P_a = F_u.A_n/ O
       O = 2.22   ASD

  c) For other than flat sheet:

     fP_n = f. F_u.(A_n.U)
      f = 0.65   LRFD

     P_a = F_u.(A_n.U) / O
       O = 2.22   LRFD

    d - nominal bolt diameter
    s - sheet width divided by number of bolt holes in cross section

  Block Shear Rupture Strength: (Eq. E5.3-1, E5.3-2)
     The lesser of following:

    LRFD
     fR_n = f [0.6 F_y.A_gv + F_u.A_nt]
     fR_n = f [0.6 F_u.A_nv + F_u.A_nt]

    ASD
     R_a = [0.6 F_y.A_gv + F_u.A_nt]/ O
     R_a = [0.6 F_u.A_nv + F_u.A_nt]/ O

    f = 0.65 for bolted connections, 0.6 for welded connections
     O = 2.22 for bolted connections, 2.5 for welded connections

    A_nt = net area subject to tension
    A_nv = net area subject to shear
    A_gv = gross area subject to shear

  Combined Bending and Tension C5.1.2

  ASD
    1).        O_b .M_x / M_nxt + O_b .M_y / M_nyt + O_t .T / T_n < = 1.0

    2).        O_b .M_x /M_nx + O_b .M_y / M_ny - O_t .T / T_n < = 1.0
  LRFD
    1).        M_ux / (f_b .M_nxt)+ M_uy / (f_b .M_nyt) + T_u / (f_t. T_n) < = 1.0

    2).        M_ux / (f_b .M_nx)+ M_uy / (f_b .M_ny) - T_f / (f_t. T_n) < = 1.0

      M_x - Required allowable flexural strength about axis X
      M_y - Required allowable flexural strength about axis Y
      T - Required allowable axial strength

       O_b = 1.67
       O_t = 1.67


      M_ux - Required flexural strength about axis X
      M_uy - Required flexural strength about axis Y
      T_u - Required axial strength

      M_nxt = S_ftx . F_y - Nominal flexural strength about axis X
      M_nyt = S_fty . F_y - Nominal flexural strength about axis Y
      S_ftx - Section modulus of full unreduced section relative to extreme tension fibre about axis X
      S_fty - Section modulus of full unreduced section relative to extreme tension fibre about axis Y

      M_nx - Nominal flexural strength about axis X
      M_ny - Nominal flexural strength about axis Y
      T_n - Nominal tensile strength

      f_b = 0.9 - resistance factor for bending
      f_t = 0.95 - resistance factor for shear