Draft

Chapter 14

BUILDING STRUCTURES

14.1 Introduction.

14.1.1 BeamColumnConnections

1 Theconnectionbetweenthebeamandthecolumncanbe, Fig. 14.1:

qb

qc

qb qc

qb =qc qb =qc

qb =qc

q

q

q

q

b b

c

c

M=K( - )

s s

Flexible Rigid Semi-Flexible

Figure14.1: Flexible,Rigid,andSemi-FlexibleJoints

Flexible thatis a hingewhich cantransferforcesonly. In thiscasewe reallyhave cantiliver

actiononly. In a
exibleconnectionthecolumnandbeamendmoments arebothequal

to zero,Mcol=Mbeam= 0. Theendrotationarenotequal,col 6 =beam.

Rigid: Theconnectionis such thatbeam=colandmoment canbe transmittedthroughthe

connection.In a rigidconnection,theendmoments androtationsareequal(unlessthere

is anexternallyappliedmoment at thenode),Mcol=Mbeam 6 = 0,col=beam.

Semi-Rigid:Theendmoments areequalandnotequalto zero,buttherotationaredierent.

beam 6 =col,Mcol=Mbeam 6 = 0. Furthermore,thedierencein rotationis resistedby

thespringMspring=Kspring(colbeam).

14.1.2 Behaviorof SimpleFrames

2 For verticalloadacrossthebeamrigidconnectionwillreducethemaximummoment in the

beam(attheexpenseof a negative moment at theendswhich willin turnbe transferredto