Cyclopedia of architecture, carpentry, and building : a general reference work . red to construct the moment diagram for thebeam. Fig. 18, a (a copy of Fig. 9), taking into account the weightof the beam, 400 pounds. The values of the bending moment for sections one foot apartwere computed in example 3, Art. 43. So we have only to lay offordinates equal to those values, one foot apart, on the base AE(Fig. 18, h). To a scale of 10,000 foot-pounds to the inch the ordinates(see example 3, Art. 43, for values of M) are: 47 I 40 stee:ngth of mateeials At left end, 0 One foot from left end, 2,480^10,
Cyclopedia of architecture, carpentry, and building : a general reference work . red to construct the moment diagram for thebeam. Fig. 18, a (a copy of Fig. 9), taking into account the weightof the beam, 400 pounds. The values of the bending moment for sections one foot apartwere computed in example 3, Art. 43. So we have only to lay offordinates equal to those values, one foot apart, on the base AE(Fig. 18, h). To a scale of 10,000 foot-pounds to the inch the ordinates(see example 3, Art. 43, for values of M) are: 47 I 40 stee:ngth of mateeials At left end, 0 One foot from left end, 2,480^10,000= inchTwo feet 3,920-^10,000= Three 5,320-^10,000= Four 6,680-^10,000= Laying these ordinates off at the proper points, we get KhcdY. as the moment line. 3. It is required to construct the moment diagram for the cantilever beam represented in Fig. 19, a, neglecting the weight of the beam. The bending moment at B equals-500x2=-l,000 foot-pounds; at C, and at D, -500 X 5-1,000 X 3=-5,500; -500 X 9-l,000x 7-2,000 X 4=-19, looolbs. eooolbs. -1^^^. Sc8Je:i= 20000 Fig. 19. Using a scale of 20,000 foot-pounds to one inch, the ordinatesin the bending moment diagram are: AtB, 1,000^20,000= inch, C, 5,500^20,0C0= D, 19,500-^20,000= Hence we lay these ordinates off, and downward because the bend-ing moments are negative, thus fixing the points J, c and d. Thebending moment at A is zero; hence the moment line connects Ah, G and d. Further, the portions Kb, ho and cd are straight, ascan be shown by computing values of the bending moment forsections in AB, BC and CD, and laying off the correspondingordinates in the moment diagram. 48 STRENGTH OF MATERIALS 41 4. Suppose that the cantilever of the preceding illustrationsustains also a uniform load of 100 pounds per foot (see Fig. 20, a).Construct a moment diagram. First, we compute the values of the bending moment at sev-eral sections; thus, M^=-500 X1-100 X i=-550 foot-pounda,M3=-500 X
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