6. Considering sag rods and tie rods at third points, what is the maximum moment about minor axis in N-m? (2 decimal places) A 20m Fink Truss are spaced at 'S' meters o.c. the purlins are made up of C10X20 sections and are spaced 1.1967m on centers. The truss has a height of 4m. Roof LL is 'RLL' N/m2 of roof surface and roof covering is assumed to be 'RDL' N/m2 of roof surface. Determine whether the purlins are adequate to carry such loadings. Fy = 248 MPa. C10X20 properties: w=29.76kg/m, A=3787.09mm2, Ix=32.84x106mm4, Iy=1.17x106mm4, Zx=317.91x103mm3, Sx=258.92x103mm3, Zy=44.25x103mm3, Sy=21.47x103mm3 S (m) RLL (N/m^2) RDL (N/m^2) 6.00 900 900

6-49. Determine the force in members HI,FI, and EFof the truss, and state if the members are in tension or compression. K 3m L B D F -2m-2m- -2m+2m- 2 m- -2 m어 4 KN 5 KN 6 kN 8 kN Probs. 6-48/49

Elementary beam theory predicts that the axial bending stress ox in a prismatic beam is given by: ox = (M.I,M,L)y+(M,I.-M.I.) (1,1₂-13/2) where My and M₂ are bending moments applied to a cross-section, and where ly, lz and lyz are second moments of area in the usual notation (Oxyz is a Cartesian coordinate system in which the x axis corresponds to the centroidal axis of the beam). (iii) A Z--section beam has the cross-section shown overleaf (see Figure QB2). The second moments of area of the section about the y and z axes are given as;; ly = 1.12x106mm² and I₂ = 2.87x106 mm4. Show that lyz = 1.35x106 mm² (use the parallel axis theorem). 100 60 10 y -10 10 60 Figure QB2 N (iv) Bending moments Mz = 2.0 kNm and My = 0 kNm act on a cross- -section of the beam of part (iii). Obtain an expression for the bending stress and sketch the orientation of the neutral axis with reference to the y and z axes. What is the maximum tensile value of the axial bending stress and where does it occur?

HW Determine the resultant force at pins A, B, and C on the three-member frame. od sdt no ol noitan 2m Ans: 800 N A, = 61.88 N A, = 569.06 N B = 338.12 N B, = 338.12 N C, = 461.88 N %3D Fc = 572 N FA = 572 N Fg = 478 N 200 N/m %3D %3D 2m %3D %3D Cy = -338.12 N 60 REDMI NOTE 9 PRO B AI QUAD CAMERA