Flexural Strngtb o Prestresoedoncrete Members
Flexura Strenlb iotomS about he res isfance ot o
malerial agdinst deformation.
Assumplions
J h e vaiofion o strain an the
Gross- section is Linear
e Stiains in the Corcrefe ad the bonde Seel are
Calculated on the assumption that plane sRctions
remain plane.
Concrete carries no tersile stress, i -e.,
the tensile
strength o the Concrefe is ignored.
h e stress in the Compressive aoncrete ard in the
Steel reintorcernert ( botth pre-stressed and
nop- Pre -Stressed) are obtained trom ackual or
idealizd stress- sttain relationshibs far the respective.
Materials.
Factors afecfing he tlex uua failures
-
Percentage of reinforcememt+ in ths sectien.
Degree bond betocen tendon and Concrete
Compressive srengih a oncrete and tutimate tensile
Strength of the tendons.
, Types of Flexural Pailure
O Fracture of' sleel io tension
failure of under -reinfored sfion
1 Faiure of over- reinforted Section
Olher modes of failure
Fradure d stel in tension -
he sudden feu lure oPsc member uithout
is
any
kue to the fra cture of stee) in tension
uworning-
generatly xone
h i s +ype of failure nifl ocur, vl
Steel provided in the echon is hen tow. percentage o
tbe
very
lhen tbe Concrete in the tension zone cracks tte steel
s not in a PostiHon to bear ub the additi
onal tensile
streas transferred to t
by the cracked Concrete
oaveid tbis tybe of failure JS: 18-13 1980 Prescribes
a minimum long itudinal reintbrement ef 0 9%
eo
e/s area
Failure ofunder-Reinforced Seciong -
maurt of R/r is less than the R/F requred for
balanced.
h i s fadure is Caused when
ncreased by excessive berduing loads are
elongation e steel nill
takes place.
h e mermber apProaches -Peilure
by gradual teduction
Com pression Zone.
Large deftechion and wide ciacks were
develobel
and this Jives waming beltore failure.
Flexura Strenlb iotomS about he res isfance ot o
malerial agdinst deformation.
Assumplions
J h e vaiofion o strain an the
Gross- section is Linear
e Stiains in the Corcrefe ad the bonde Seel are
Calculated on the assumption that plane sRctions
remain plane.
Concrete carries no tersile stress, i -e.,
the tensile
strength o the Concrefe is ignored.
h e stress in the Compressive aoncrete ard in the
Steel reintorcernert ( botth pre-stressed and
nop- Pre -Stressed) are obtained trom ackual or
idealizd stress- sttain relationshibs far the respective.
Materials.
Factors afecfing he tlex uua failures
-
Percentage of reinforcememt+ in ths sectien.
Degree bond betocen tendon and Concrete
Compressive srengih a oncrete and tutimate tensile
Strength of the tendons.
, Types of Flexural Pailure
O Fracture of' sleel io tension
failure of under -reinfored sfion
1 Faiure of over- reinforted Section
Olher modes of failure
Fradure d stel in tension -
he sudden feu lure oPsc member uithout
is
any
kue to the fra cture of stee) in tension
uworning-
generatly xone
h i s +ype of failure nifl ocur, vl
Steel provided in the echon is hen tow. percentage o
tbe
very
lhen tbe Concrete in the tension zone cracks tte steel
s not in a PostiHon to bear ub the additi
onal tensile
streas transferred to t
by the cracked Concrete
oaveid tbis tybe of failure JS: 18-13 1980 Prescribes
a minimum long itudinal reintbrement ef 0 9%
eo
e/s area
Failure ofunder-Reinforced Seciong -
maurt of R/r is less than the R/F requred for
balanced.
h i s fadure is Caused when
ncreased by excessive berduing loads are
elongation e steel nill
takes place.
h e mermber apProaches -Peilure
by gradual teduction
Com pression Zone.
Large deftechion and wide ciacks were
develobel
and this Jives waming beltore failure.
