Solution Manual Steel Structures Design And Behavior -

LRFD: ( \phi_t = 0.75 ) → ( P_d = 0.75 \times 129.5 = 97.1 \text{ kips} ) ASD: ( \Omega_t = 2.00 ) → ( P_a = 129.5 / 2.00 = 64.8 \text{ kips} )

Block shear rupture strength (AISC Eq J4-5):

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 ). solution manual steel structures design and behavior

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.

Better to follow AISC manual example: For L4×4×½ connected with 3 bolts, block shear strength:

For L4×4×½: ( \bar{x} = 1.13 \text{ in} ) (from AISC Manual). Length of connection ( L ) = distance between first and last bolt = 2 pitches = 6 in. LRFD: ( \phi_t = 0

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.

Gross shear length = ( 1.5 + 3 + 3 = 7.5 \text{ in} ) (from edge to last bolt). Net shear length = ( 7.5 - 2.5 \times d_h = 7.5 - 2.5 = 5.0 \text{ in} ) (since 2.5 holes along shear path? Actually 2.5 holes for two lines? Need precise – typical simplified: net shear area = ( (7.5 - 2.5*(1.0))*0.5 = 2.5 \text{ in}^2 ) per plane, two planes = 5.0 in²).

Tension member connected to gusset plate – check block shear along bolt group. However, typical solution uses two holes: ( A_n

Given edge distance = assume 1.5 in (standard), spacing = 3 in, hole diameter = 1 in, thickness = 0.5 in.

Thickness ( t = 0.5 \text{ in} ). Two hole diameters in the failure path (assuming worst path goes through both holes in the same leg – check path 1-2-3).

[ P_{n, yielding} = F_y \cdot A_g = 36 \cdot 3.75 = 135 \text{ kips} ]