[ P_{n, yielding} = F_y \cdot A_g = 36 \cdot 3.75 = 135 \text{ kips} ]
Check alternative staggered path through first hole in one leg then to hole in opposite leg? For L4×4, gage between legs (distance from back of one leg to center of holes in other leg) ≈ 2.5 in (AISC gage for angles). But given gage = 2.0 in, stagger term: ( s^2/(4g) = 3^2/(4 2) = 9/8 = 1.125 ). For one diagonal path: ( A_n = A_g - 2 (d_h t) + (1.125 t) ) = ( 3.75 - 1.0 + 0.5625 = 3.3125 \text{ in}^2 ) → larger than 2.75, so critical net area = 2.75 in².
Yielding: LRFD 121.5 kips, ASD 80.8 kips Fracture: LRFD 97.1 kips, ASD 64.8 kips →
So ( R_n = 191 \text{ kips} ) (lower governs). This is much higher than tensile fracture or yielding – thus block shear does not control. solution manual steel structures design and behavior
Tension member connected to gusset plate – check block shear along bolt group.
[ R_n = 0.6 F_u A_{nv} + U_{bs} F_u A_{nt} \quad \text{with } U_{bs}=1.0 \text{ (uniform tension)} ] [ R_n = 0.6 \times 58 \times 5.0 + 1.0 \times 58 \times 0.5 = 174 + 29 = 203 \text{ kips} ] But limited by ( 0.6 F_y A_{gv} + U_{bs} F_u A_{nt} = 0.6 \times 36 \times 7.5 + 29 = 162 + 29 = 191 \text{ kips} )
Tension net area across last bolt row = (gage distance – one hole) * t = ( (2.0 - 1.0)*0.5 = 0.5 \text{ in}^2 ) per plane? Two planes? For single angle, block shear occurs in the connected leg only. [ P_{n, yielding} = F_y \cdot A_g = 36 \cdot 3
Assume failure path: tension on net area across the end row, shear on two net areas along both sides of bolt group.
Path 1: straight line through both holes (no stagger effect since in same leg, but stagger formula still applies if line zigzags – here, holes are in same leg, so stagger not applied unless crossing to other leg? For angles, net section often through holes in same leg, stagger effect negligible for two holes on same line. However, typical solution uses two holes: ( A_n = A_g - 2 \cdot (d_h \cdot t) ) = ( 3.75 - 2 \cdot (1.0 \cdot 0.5) = 3.75 - 1.0 = 2.75 \text{ in}^2 ).
[ A_n = A_g - \sum (d_h \cdot t) + \sum \left( \frac{s^2}{4g} \cdot t \right) ] For one diagonal path: ( A_n = A_g - 2 (d_h t) + (1
Block shear rupture strength (AISC Eq J4-5):
[ A_{gv} = 2 \times ( \text{shear length along bolt line}) \times t = 2 \times 7.5 \times 0.5 = 7.5 \text{ in}^2 ] [ A_{nv} = A_{gv} - 2 \times (2.5 \times d_h \times t) \quad \text{(2.5 holes per shear plane)} = 7.5 - 2 \times (2.5 \times 1.0 \times 0.5) = 7.5 - 2.5 = 5.0 \text{ in}^2 ] [ A_{nt} = ( \text{gage} - d_h) \times t = (2.0 - 1.0) \times 0.5 = 0.5 \text{ in}^2 ]