Truss Analysis of Pile caps
r
onolysisof pil cc|
II Truss
Tridibesh Indu
I
TheprhrciryIes of nnt:tlry:;is illustratedf1la '4 pile, re:ctangular cdp ttnder ltinxinlly eccutric column loadhaaebeen Uilisea
.
fr: : ft:ut types of cnp,sih respectof the applicqtion orld scope
,f the truss rttethod.
The analyseshave been limited to the deterrninationof pilg loadsand the te:nsileforcein the reinforcementat bottom. th"
3
verification of s lear strengthpre$entFno speclalfeatureer,a
,
The casesshrdieclare shown in Fig1
Polygonalcap P-1 .
.
Tlne conditions of equilibrium are :
Rnffrr*Rc.=P
(1)
7\, = Tru, 7'or,= Tr-o
(2)
The useof the'seequirtionr;areptplained Wtthreferenceto Fig 2, in which o' is the f:rroJectiun df iiode p dh ilia hpgzonul prJne
'
The forcesin the stnlls are:
c,"=n^ff C u uR=r+,
coc=&
#
T_
ri
Their projectiorrsorr the horizontal plane given by Ao',
__
BO' and CO', respectivglyareas show4 : l I
oA'-. % c^,%.R. ' '.r,!
'*.4
R.. uruIR^oc
"0A
f
0A
h
It
L___*_
h
l
The forcesin the ties,
.AD
Tou=& and l?
Q"*Rrry
(3)
are obtained with the aid of parallelogram of forces.
Tridibeshlndu,.r\ssistatrl
DesignEntrlineer,
STUPConsultants l-trl.,Calcutta. tieptember 1997 *
'l'lre
lndian Cnnchte Journ*l
Fig 1
R'1
'-.l
II
I
I
I
I
/
$tr-- :lf,',"
/
c
F
0-0 99 p
02t8P
t0.5Bo'
x-"
ao'
'do-s
'\
/\\
/
,\
(/
o
.J
t
Q)
)
()
Or
/
0.cc r. 0 661 q . =
PL h Fig 3 Hexagonalpile cap of side 'L'
Rc=S#Rn =2.8r3q1
AD_
^
T A B - T n ag i v e s & = ; ; &
(aa)
trIJ
Tac=Tcngives R. =
1:'
q ri'} ;
. . i r . ' i r e,
l
, r r
;l
lCA, = Ie,C
!
glves
BF h
*&
=
BF
AD_
**#*^
R.= frn^ RD=
(4b)
a
*t;e *au
RF=HRE=l.tzlnA
(5)
uld R. follows from equatio'r(4)and the forcesT^,,T
S
r.^
T., furn Eqn. (3).
I
u-xrytple,l: Hexagonalpile cap l;$k dimdruions in Frg3 are obtained graphically.
= 3.345q,r x 2.8l3RA
Ra=ffi Ro=I.9B2RA
(ac)
and g- = Y*.* pro'ides a checkonnumericalor
CH CG BE gtuphical work.
=ffi
Usingeqn.(1),^.
#
Iffi
rll--jt--Jl
'^l
..
I'
il
onolysisof pil cc|
II Truss
Tridibesh Indu
I
TheprhrciryIes of nnt:tlry:;is illustratedf1la '4 pile, re:ctangular cdp ttnder ltinxinlly eccutric column loadhaaebeen Uilisea
.
fr: : ft:ut types of cnp,sih respectof the applicqtion orld scope
,f the truss rttethod.
The analyseshave been limited to the deterrninationof pilg loadsand the te:nsileforcein the reinforcementat bottom. th"
3
verification of s lear strengthpre$entFno speclalfeatureer,a
,
The casesshrdieclare shown in Fig1
Polygonalcap P-1 .
.
Tlne conditions of equilibrium are :
Rnffrr*Rc.=P
(1)
7\, = Tru, 7'or,= Tr-o
(2)
The useof the'seequirtionr;areptplained Wtthreferenceto Fig 2, in which o' is the f:rroJectiun df iiode p dh ilia hpgzonul prJne
'
The forcesin the stnlls are:
c,"=n^ff C u uR=r+,
coc=&
#
T_
ri
Their projectiorrsorr the horizontal plane given by Ao',
__
BO' and CO', respectivglyareas show4 : l I
oA'-. % c^,%.R. ' '.r,!
'*.4
R.. uruIR^oc
"0A
f
0A
h
It
L___*_
h
l
The forcesin the ties,
.AD
Tou=& and l?
Q"*Rrry
(3)
are obtained with the aid of parallelogram of forces.
Tridibeshlndu,.r\ssistatrl
DesignEntrlineer,
STUPConsultants l-trl.,Calcutta. tieptember 1997 *
'l'lre
lndian Cnnchte Journ*l
Fig 1
R'1
'-.l
II
I
I
I
I
/
$tr-- :lf,',"
/
c
F
0-0 99 p
02t8P
t0.5Bo'
x-"
ao'
'do-s
'\
/\\
/
,\
(/
o
.J
t
Q)
)
()
Or
/
0.cc r. 0 661 q . =
PL h Fig 3 Hexagonalpile cap of side 'L'
Rc=S#Rn =2.8r3q1
AD_
^
T A B - T n ag i v e s & = ; ; &
(aa)
trIJ
Tac=Tcngives R. =
1:'
q ri'} ;
. . i r . ' i r e,
l
, r r
;l
lCA, = Ie,C
!
glves
BF h
*&
=
BF
AD_
**#*^
R.= frn^ RD=
(4b)
a
*t;e *au
RF=HRE=l.tzlnA
(5)
uld R. follows from equatio'r(4)and the forcesT^,,T
S
r.^
T., furn Eqn. (3).
I
u-xrytple,l: Hexagonalpile cap l;$k dimdruions in Frg3 are obtained graphically.
= 3.345q,r x 2.8l3RA
Ra=ffi Ro=I.9B2RA
(ac)
and g- = Y*.* pro'ides a checkonnumericalor
CH CG BE gtuphical work.
=ffi
Usingeqn.(1),^.
#
Iffi
rll--jt--Jl
'^l
..
I'
il