Analysis ot Pre-streas
tnalysis is the deBerminotion st shesses in the steel
and Con c ree w hen the or m and size ot a Section are
already iven or aysumed.
Sresses in Concrete are calcudaed by the use
efoshic tbtory.
he onolysis ePresttessed members can be dieret
for the diHerent stages olooding
At initio 3to2e
t be sub-divided ite tuwe
Con
stages-
During tensioning steel
GH ttansfer o prestress te Cohcrete
ltIntemediatedage
lhis includes the lods during handling, ttansportation
and erection o the pre- shess m embers,
+ tinal stage -
Can be sub- dlivided irrte tuwo stages3
A t service , duting operation
P t uHimat, during extreme evenis.
dhe most critical load'ng Conditions are -
Jnitial loadlina tonsfer)
Anal Loading (Service)
, Assumptions
Concrele is o homogehous elatic material
Within the range wor King stress, both Ctncrefc
and steel behove elastica0y
PMone ection belore bending. is assumed t s remaid
Plone Her bencing also.
Methods o etnalysis ef Pre-stress-
both loaods
Jhe resuHart 6ttess e the section depends on
tocation e tedorn.
De ad load and. Live toad) and the
Types tendon profite -
Based on position
Concentric tendon N A
Ten don
) Eccetric tendon . A
LHendon
2) Based on shape
i) Parabslic tendon Tendorn
N A
)rapezotd al terdon t Tendon
- A
) Sloping tendon
N Tendon
A
, Jhere are thsee abproaches tor analyse c
pre-sBressecd
member at transfer and under service loods.
Jhese abbroaches are based on the
fo|louoing Concepts-
Stress Concebt ( Extreme fiber tresses)
Strength contet (Shitt oPressure line)
Load balaneing Concebt
(upuoard force neuralize
the douon uard force)
Stress Concept
he stress ccncept is usedto compare the caculote
stresses with the aUouwable sfresses.
Beam with Concentric endon and without
clead, ive loaols-
E
9tress clistributiom due to Stress
without dead and ve Load Concentric tenclon A
RS at te =
Rs at bottom Direct
-
Compressive Stress = + (A
Loss satip =Final Presress force
Jnitial Prestress torce
Let
toss = 1S
loss rotio = 8S Z
tnalysis is the deBerminotion st shesses in the steel
and Con c ree w hen the or m and size ot a Section are
already iven or aysumed.
Sresses in Concrete are calcudaed by the use
efoshic tbtory.
he onolysis ePresttessed members can be dieret
for the diHerent stages olooding
At initio 3to2e
t be sub-divided ite tuwe
Con
stages-
During tensioning steel
GH ttansfer o prestress te Cohcrete
ltIntemediatedage
lhis includes the lods during handling, ttansportation
and erection o the pre- shess m embers,
+ tinal stage -
Can be sub- dlivided irrte tuwo stages3
A t service , duting operation
P t uHimat, during extreme evenis.
dhe most critical load'ng Conditions are -
Jnitial loadlina tonsfer)
Anal Loading (Service)
, Assumptions
Concrele is o homogehous elatic material
Within the range wor King stress, both Ctncrefc
and steel behove elastica0y
PMone ection belore bending. is assumed t s remaid
Plone Her bencing also.
Methods o etnalysis ef Pre-stress-
both loaods
Jhe resuHart 6ttess e the section depends on
tocation e tedorn.
De ad load and. Live toad) and the
Types tendon profite -
Based on position
Concentric tendon N A
Ten don
) Eccetric tendon . A
LHendon
2) Based on shape
i) Parabslic tendon Tendorn
N A
)rapezotd al terdon t Tendon
- A
) Sloping tendon
N Tendon
A
, Jhere are thsee abproaches tor analyse c
pre-sBressecd
member at transfer and under service loods.
Jhese abbroaches are based on the
fo|louoing Concepts-
Stress Concebt ( Extreme fiber tresses)
Strength contet (Shitt oPressure line)
Load balaneing Concebt
(upuoard force neuralize
the douon uard force)
Stress Concept
he stress ccncept is usedto compare the caculote
stresses with the aUouwable sfresses.
Beam with Concentric endon and without
clead, ive loaols-
E
9tress clistributiom due to Stress
without dead and ve Load Concentric tenclon A
RS at te =
Rs at bottom Direct
-
Compressive Stress = + (A
Loss satip =Final Presress force
Jnitial Prestress torce
Let
toss = 1S
loss rotio = 8S Z
