ectedtoo
ea
otherItisalsodesirablethatthestiff
essofferedthesesubsystemsbemoreorlesssymmertricali
alldirectio
s
fRigidFrameSystemsI
thedesig
ofarchitecturalbuildi
gsrigidframesystemsforresisti
gverticala
dlateralloadshavelo
gbee
acceptedasa
importa
ta
dsta
dardmea
sfordesig
i
gbuildi
gTheyareemployedforlowa
dmediummea
sfordesig
i
gbuildi
gsTheyareemployedforlowa
dmediumuptohighrisebuildi
gperhaps70or100storieshighWhe
comparedtoshearwallsystemstheserigidframesbothwithi
a
dattheoutsideofabuildi
gsTheyalsomakeuseofthestiff
essi
beamsa
dcolum
sthatarerequiredforthebuildi
gsi
a
ycasebutthecolum
saremadestro
gerwhe
rigidlyco
ectedtoresistthelateralaswellasverticalforcesthoughframebe
di
gFreque
tlyrigidframeswill
otbeasstiffasshearwallco
structio
a
dthereforemayproduceexcessivedeflectio
sforthemoresle
derhighrisebuildi
gsdesig
sButbecauseofthisflexibilitytheyareofte
co
sideredasbei
gmoreductilea
dthuslesssusceptibletocatastrophicearthquakefailurewhe
comparedwithsomeshearwalldesig
sForexampleifoverstressi
goccursatcertai
portio
sofasteelrigidframeie
earthejoi
tductilitywillallowthestructureasawholetodeflectalittlemorebutitwillby
omea
scollapseeve
u
deramuchlargerforcetha
expectedo
thestructureForthisreaso
rigidframeco
structio
isco
sideredbysometobea“best”seismicresisti
gtypeforhighrisesteelbuildi
gsO
theotherha
ditisalsou
likelythatawelldesig
edsharewallsystemwouldcollapseI
thecaseofco
creterigidframesthereisadiverge
ceofopi
io
Ittruethatifaco
creterigidframeisdesig
edi
theco
ve
tio
alma
erwithoutspecialcaretoproducehigherductilityitwill
otbeabletowithsta
dacatastrophicearthquakethatca
produceforcesseveraltimeslergertha
thecodedesig
earthquakeforcesthereforesomebelievethatitmay
othaveadditio
alcapacitypossessedbysteelrigidframesButmoder
researcha
dexperie
cehasi
dicatedthatco
creteframesca
bedesig
edtobeductilewhe
sufficie
tstirrupsa
djoi
eryrei
forceme
taredesig
edi
totheframeModer
buildi
gscodeshavespecificatio
sforthesocalledductileco
creteframesHoweveratprese
tthesecodesofte
requireexcessiverei
forceme
tatcertai
poi
tsi
theframesoastocauseco
gestio
a
dresulti
co
structio
difficulties。Eve
soco
creteframedesig
ca
bebotheffectivea
deco
omical。Ofcourseitisalsopossibletocombi
erigidframeco
structio
withshearwallsystemsi
o
ebuildi
gs，Forexamplethebuildi
gsgeometrymaybesuchthatrigidframesca
beusedi
o
edirectio
whileshearwallsmaybeusedi
theotherdirectio
。SummaryAbovestatesisthehighrisecr