Tensile Strength:
    for A307, 60 ksi,   for A325, 120 ksi,   for A490, 150 ksi

  Slip-critical pretension:
    70% of the minimum tensile strength

  Combined Shear and Tension for Bearing Type Connections
     f_t / (f . F_nt) + f_v / (f .F_nv) <= 1.3    LRFD
     O .f_t / F_nt + O .f_v / F_nv <= 1.3    ASD

    f = 0.75,     O = 2.0
    f_t - the required tensile stress
    f_v - the required shear stress
    F_nt - nominal tensile stress
    F_nv - nominal shear stress

  Combined Shear and Tension for Slip-Critical Connections
     k_s = 1 - T / (1.13 T_b. N_b)  
    k_s - slip resistance reduction factor
    T - the required strength
    T_b- 70% of the minimum tensile strength
    N_b - number of bolts carrying the applied tension

  Edge Distance
  1). Minimum end distance
     L_e >= 1.5d
  2). Maximum end distance
    L_e <= 12 t, and 6 in.

  Spacing of Bolts
  1). Minimum Spacing
     S >= 2.7 d
  2). Maximum Spacing
    S <= 24.t and 12 in.