Draft

8.4Forces 161

Mext = Cd)C=

Mext

d

(8.4-a)

T=C =

(808)k.ft

(9:2)ft

=  88 k (8.4-b)

8 Becausetheframeshape (andthusd(x)) is approximatelyparabolic,andthemoment is also

parabolic,thentheaxialforcesareconstants alongtheentireframe,Fig.8.7.

MOMENT DIAGRAM

M

CURVE OF DIAGRAM

CABLE : FRAME :

SHAPE OF DIAGRAM

FRAME

d

Figure8.7: MagazziniGenerali;SimilaritiesBetweenTheFrameShape anditsMoment Dia-

gram,(BillingtonandMark1983)

9 Theaxialforceat theendof thebeamis notbalanced,andthe 88 kipcompressionmustbe

transmittedto thelower chord,Fig.8.8. Fig. 8.9Thisis analogousto theforcestransmiited

Tied Arch

Cable Force

Vertical Reaction

Horizontal Component

Axial Force

Compression

88 k

88 k

88 k Tension

88 k

Figure8.8: MagazziniGenerali;Equilibriumof Forcesat theBeamSupport,(Billingtonand

Mark1983)

to thesupportby a tiedarch.

10 It shouldbe mentionedthatwhena rigorouscomputeranalysiswas performed,it was de-

terminedthatthesupportsarecontributinga compressionforceof about8 kipswhich needs

to be superimposedover thecentralvalues,Fig.8.9.