Develop checklists for the design of simple bearing and slip

Develop checklists for the design of simple bearing and slip-critical connections using a) common bolts, and b) high-strength bolts. Summarize the equations that should be checked in each step of each list.

Solution

Slip crictical connections are used when:

-Stress reversal, impact or vibration present

-joint slippage would be detrimental to servicability

Slip critical connection can fail in two ways

1. Slip at connection

2. bearing failure at the connection

So checklist includes

1.resist slip at load service

2.shear strength limit states

a)

Common bolts are designated as ASTM A307, ultimate shear strength of 24ksi.

shear strength R_n= F_vA_b   F_v- ultimate shearing stress=24

A_b-cross sectional area of unthreaded part.

slip resistance= K_hK_sN_sP_t   P_t--minimum required bolt tension

K_h--hole factor

K_s--Surface condition factor

  

When connection subjected to tensile force, slip resistance should be reduced by (1-T_u/P_t)

b)

For High strength bolts come in two grades

-ASTM A325

-ASTM A490

shear strength=F_vA_b   F_v- ultimate shearing stress=48 or 60 or 75 etc.

slip resistance= K_hK_sN_sP_t