Question

The compound heam is made from two sections, which are pinned together at B. Use Appendix B and select the lightest-weight wide-flange beam that would be safe for cach section if the allowable bending stress is allow = 24 ksi and the allowable shear stress is Tallicw = 14 ksi. The beam supports a pipe loading of 1000 lb and 2000 lb as shown. 1000 lb 2000 lb oft- -6- 8 - 10ft-

Answer 1

엄 BC take momert about 8, + Ms O Consides FBD R1)(2x3) = O 2 x 8 = 0. 889 kip Rc = 8 2 kip Re+ Re 2- O-889 = 1-11 Kip RB 2- R= Considers FBD of AB RA=1 1-1 = 2. || kip R= 2.11 kip (Ix6)+(HI12) 19.32 kip t EMA MA = 19.32 kip l Re= O. 889 kip 1-11 kip RB RA s 2. kip 19.32 kip. st = 19.32x 12 231.84 kip. in. MA

11 calculadion 5FD +ve 3FD: -ve -ve BMD: +ve 5F CA)= 2.1 kip SF (D)= 2.11 kip 9-2 3F (D)= +2 11 1 1 kip (6) = 2=12 +2. 1-1= 1-1 kip 5 F 5F (E) +2.11- 1-1 kip 5F CE)= t 2-11-1-2 O. 89 Kip 230 = O.89 kip SF (C BMD calculedion CA) -19. 32 kip- t- - MA = CD)- -MA + (2.11 x6)= -19.32t (2-11x6) BMEF (D) = 6 66 kip -MAt (2.11 x12) - -19.32 + (2-11 x12)-6 BM (B) X=12' -xa BM(B) = O = -MA (Ix14)+ (2-11x20) (x4)(2-11x20) BM (e) 20 = -19.32 8-88 kip ft BM (E) O kip ft X=30 BM ()=

aooo lb2 kip Io0olb I Kip A 644 10st 計8 Consides two section (le ight side ef pin B) 1 kip Ra 11 Kip MA= 19.32 kip 2kip A B . R=2 kip C 1241 Re= O-889 kip Re= l-1| kip 18J 2.1 2.11 kip 5FD . C A -O.89 -o.89 & 8.8 C BMD -G.66 Kip. ft -19.32

Bencing 6tress Memberr AG o BMO, 19.32 kip. t Mman kip in Mmax 19-32 kip. 031. 84 Apply slenwe fonmls 231- 84 Mman Sm 4 aulow 9.6G in eg (5x- 10.9 in3, d- 9.87 in Aw= O19 in) Se lect W 10 X 12 Apply rom BMD, the same putedune Jo member BC 8-89 kip t Mman 10 Gckip in 8-89 X 12 . Mman= tO0.68 Mman 4.4 45 in a 4 6allow (5= 5. S6in d 510 in 0.1n) Selecl W Gx

two sections Now we Check it fo ahear atnen foum 5FD, Vm 2-1 kp Jon membe AB, 2. O-19 x 9.87 = *2 (Ok) 1-125 ksi al 14 ksi Cmanx allou Jomemben BC, om 6FD, Vman = l-11 kip = 1. 10 61 kai 11 d O.17x S.90 OK mon 1067 ksi Calous Answer W 10X12 Member AB Member BC