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Brockenbrough_Ch03.qxd  9/29/05  5:05 PM  Page 3.62



                                                        CONNECTIONS


                   3.62  CHAPTER THREE

                               Check that a < 1.25b = 1.25 × 2.035 = 2.544. Since a = 1.3125 < 2.544, use a = 1.3125 in. If a >
                               1.25b, a = 1.25b should be used.


                                                          .
                                                                .
                                                    .
                                                b ′ = 2 035 −  0 875  = 1 598 in
                                                           2
                                                           .
                                                a ′ = 1 3125 +  0 875  = 175 in
                                                    .
                                                                 .
                                                            2
                                                 ρ  =  ′ b  = 091
                                                        .
                                                     ′ a
                                                 p  = 3 in
                                                             .
                                                 δ  =−  ′ b  =−  0 9375  = 0 6875.
                                                         1
                                                   1
                                                      p       3
                                                           
                                                α ′ =  1   t c  2  −  1 
                                                         
                                                           
                                                    δ 1 (  + ρ)   t  
                                                           ′′
                                                         φ )
                                                                           .
                                                                  .
                                                      .(
                                                          t
                                                                                 .
                                                t c  =  4 44 rb  =  4 44  × 40 6 .  ×1 598  = 1 215 in
                                                                      ×
                                                        pF u         365
                                                                .
                                                α ′ =   1        1 215  2  −  1   = 144
                                                                           .
                                                    0 6875 ×1 91    0 715   
                                                     .
                                                           .
                                                                .
                               Since α′ > 1, use α′ = 1 in subsequent calculations. α′ = 1.44 means that the bending of the W16 ×
                               57 flange will be the controlling limit state. The bolts will not be critical, that is, the bolts will not
                               limit the prying strength. The design tensile strength T d per bolt including the flange strength is
                                              t   2         .    2
                                      T = φ r′   1 (  + δ)  = 40 6 .  ×   0 715   ×1 6875 23 7 .  kips  > 5 96 kips  OK
                                                                         =
                                                                     .
                                                                                    .
                                       d
                                           t
                                             t  
                                                             1 215
                                                             .
                                              c
                                 In addition to the prying check on the piece W16 × 57, a check should also be made on the flange
                               of the W18 × 50 beam. See Art. 3.7.3. Thus,
                                                   b =  4.5 − 0.355  = 2.073 in
                                                          2
                                                   a =  75 .  − 45 .  = 150.   in
                                                         2
                                                   n = 4
                                                   p =  in3
                                                            +
                                                       (
                                                  p eff  =  3 4  −1) (π  × 2 073.  )  + 2(  ×1 50.  )  = 463  in
                                                                                .
                                                                 4
                               Following the procedure in the AISC Manual,
                                                                b
                                                             b == 2 073  in
                                                                    .
                                                             a = 1 3125 in
                                                                 .
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