Essentials in the theory of framed structures . erature Member inchesI changet It Ui Uu, 1-3 324 -l-io +3, 240 — -3,240 3-S 324 + 10 -1-3, 240 — -3,240 S-7 324 -hio -1-3, 240 -o-S — 1,620 7-9 324 -hio -1-3,240 -o-S — 1,620 0-2 324 -IS —4,860 -Ko-S -2,430 2-4 324 -IS -4,860 + -2,430 4-6 324 -IS —4,860 -3>64S 6-8 324 -IS -4,860 -t-o-7S -3,64s 8-10 324 -IS —4,860 -i,2iS 10-12 324 -IS -4,860 -1,215 SUU4 = —24,300 298 THEORY OF FRAMED STRUCTURE Chap. VII the computation may be arranged as in Table II. The verticaldisplacement of point 4 is A4 = SZ/M4 X
Essentials in the theory of framed structures . erature Member inchesI changet It Ui Uu, 1-3 324 -l-io +3, 240 — -3,240 3-S 324 + 10 -1-3, 240 — -3,240 S-7 324 -hio -1-3, 240 -o-S — 1,620 7-9 324 -hio -1-3,240 -o-S — 1,620 0-2 324 -IS —4,860 -Ko-S -2,430 2-4 324 -IS -4,860 + -2,430 4-6 324 -IS —4,860 -3>64S 6-8 324 -IS -4,860 -t-o-7S -3,64s 8-10 324 -IS —4,860 -i,2iS 10-12 324 -IS -4,860 -1,215 SUU4 = —24,300 298 THEORY OF FRAMED STRUCTURE Chap. VII the computation may be arranged as in Table II. The verticaldisplacement of point 4 is A4 = SZ/M4 X = — in. The negative sign indicates that the point 4 is raised by theeffect of the temperature. The problem may be solved graphically by drawing a Williotdiagram and using the quantities It in Table II, to represent thechanges in length. 183. Camber.—It is desirable that the truss in Fig. 175, whenloaded, shall have the configuration represented by the fulllines, rather than by the dotted lines. In order to accomplish. Fig. 188. this end, it is necessary to camber the truss, by increasing the length of each compression member and decreasing the length of each tension member by the amount of strain which it experiences under load. Thus, in Fig. 176, the strain in the member 1-3 from Table I is —3,380 X 1,000 , . —^^^ = — 29,000,000 This member is shortened about one-eighth of an inchwhen the truss is loaded, hence its original length is made 27-o%. If all members are treated accordingly, and the trusserected on false work, in such a way that the members arecarrying little or no stress; the truss will have the configurationof Fig. 188; which is known as a camber diagram. The camberdiagram is constructed from a Williot diagram, drawn byusing the strains as given in column 4 of Table I, with oppositesigns. Trusses are usually cambered for dead load plus liveload, impact not included; sometimes the dead load plus two-thirds the live load is tak
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectstructu, bookyear1922
