ouldbewelloiledafterclea
i
gthema
dtherei
forceme
tshouldbeclearedofrusta
dotherharmfulmaterialsI
fou
datio
stheearthshouldbecompacteda
dthoroughlymoiste
edtoabout6i
i
depthtoavoidabsorptio
ofthemoistureprese
ti
thewetco
creteCo
creteshouldalwaysbeplacedi
horizo
tallayerswhicharecompactedbymea
sofhighfreque
cypowerdrive
vibratorsofeithertheimmersio
orexter
altypeasthecaserequiresu
lessitisplacedbypumpi
gItmustbekepti
mi
dhoweverthatovervibratio
ca
beharmfulsi
ceitcouldcausesegregatio
oftheaggregatea
dbleedi
goftheco
crete
6
f唐山学院毕业设计Hydratio
oftheceme
ttakesplacei
theprese
ceofmoistureattemperaturesabove50°FItis
ecessarytomai
tai
suchaco
ditio
i
orderthatthechemicalhydratio
reactio
ca
takeplaceIfdryi
gistoorapidsurfacecracki
gtakesplaceThiswouldresulti
reductio
ofco
cretestre
gthduetocracki
gaswellasthefailuretoattai
fullchemicalhydratio
Itisclearthatalarge
umberofparametershavetobedealtwithi
proportio
i
garei
forcedco
creteeleme
tsuchasgeometricalwidthdepthareaofrei
forceme
tsteelstrai
co
cretestrai
steelstressa
dsoo
Co
seque
tlytriala
dadjustme
tis
ecessaryi
thechoiceofco
cretesectio
swithassumptio
sbasedo
co
ditio
satsiteavailabilityoftheco
stitue
tmaterialsparticulardema
dsoftheow
ersarchitecturala
dheadroomrequireme
tstheapplicablecodesa
de
viro
me
talrei
forcedco
creteisofte
asiteco
structedcompositei
co
trasttothesta
dardmillfabricatedbeama
dcolum
sectio
si
steelstructuresAtrialsectio
hastobechose
foreachcriticallocatio
i
astructuralsystemThetrialsectio
hastobea
alyzedtodetermi
eifits
omi
alresisti
gstre
gthisadequatetocarrytheappliedfactoredloadSi
cemoretha
o
etrialisofte
ecessarytoarriveattherequiredsectio
thefirstdesig
i
putstepge
eratesi
toaseriesoftriala
dadjustme
ta
alysesThetriala
dadjustme
tproceduresforthechoiceofaco
cretesectio
leadtotheco
verge
ceofa
alysisa
ddesig
He
ceeverydesig
isa
a
alysiso
ceatrialsectio
ischose
Theavailabilityofha
dbookschartsa
dperso
alcomputersa
dprogramssupportsthisapproachasamoreefficie
tcompacta
dspeedyi
structio
almethodcomparedwiththetraditio
alapproachoftreati
gthea
alysisofrei
forcedco
creteseparatelyfrompuredesig
22Earthwork
Becauseearthmovi
gmethodsa
dcostscha
gemorequicklytha
thosei
a
yotherbra
chofcivile
gi
eeri
gthisisafieldwheretherearerealopportu
itiesforthee
thusiastI
1935mostofthemethods
owi
useforcarryi
ga
dexcavati
gearthwithrubbertyredequipme
tdid
otexistMostearthwasmovedby
arrowrailtrack
owrelativelyrarea
dthemai
methodsofexcavatio
withfacesr