esfuerzos permisibles en el concreto y en el acero

7/23/2019 Esfuerzos Permisibles en El Concreto y en El Acero

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2. DETERMINACIN DE LOSESFUERZOS PERMISIBLES EN ELCONCRETO (ACI-318-02)

DATOS:

fc = 420 kg/cm2

fci= 0.7 fc


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2.1. FASE INICIAL.

a)fti 0.8 fci

fti = (0.8)

(0.7)(420) = 13.72kg

/cm2

b)

fci - 0. fci

f = -0. 0.7 420 = -17.40


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2.2. FASE FINAL.

a)ft! 1. fc

ft! = (1.)

(420) = 32.7"kg

/cm2

b)fc! -0.4# fc

fc! = (-0.4#) (420) = -18".00 kg/cm2


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2.3. COMPARACIN DE LOSESFUERZOS.

$% &a tab&a '* +,!

% & c%c,t !& !

*!a,,&&a% !f,! *cm',%!i%.


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$& a, * &&! c,, % &a fa!%icia& a& c%t, *& c&a, !:

f2i = -17.4# kg/cm2

m'a,a* c% & ',mi!ib& *:

fci = -17.40k

g/cm2

5, & ! ac'ta a !tam! %

& &6mit ',miti*.


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3. DETERMINACIN DE LOSESFUERZOS EN EL ACERO DEPRESFUERZO.

a) $ $ T$SADO (5O9 A A5A

D$ ;ATO).

b) $ A ).

c) $ A >*


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A'= 7.2 cm2

(48 cab&! t,%a*! * 7 @i&! *iBmt,0. i%)

$'= 1.8" C 10kg/cm2

(5a,a cab&! t,%a*!)

DATOS:


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a) $% & t%!a* (', &a a'&icaci% *&;at).

f'= 5/A'

5 = 5i /0."= 8#00.00 /0."

SOE:

f'= $!f, * T%!a*.

5=


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b) $% &a fa! i%icia& * t,a%!mi!i% % &c%t, *& c&a,.

f'i= 5i/A' %'fc

%'= G%'= $'/ $c= 1.8" C 10 / 1#100 (0.7)(420)

$c= 1#100 fcifci= 0.7 fc

%'= 7.3


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fc= G ($!f, % & c%c,t *bi* a& 5! ','i)

fc = /c = (2280000) (42.14) / "84142"

fc = "7.11kg

/cm2

f'i = 8#00/7.20 (7.30) ("7.11)

f'i = 128"4.3# 708."0 = 1303.2#kg/cm2

"4.7"H #.21H 100H


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c) $% &a fa! I%a& % & c%t, *& c&a,.

f'= 5/A' %'fc!

%' = $'/$c= 1.8" C 10 / 1#100 (420)

$c = 1#100fc

%' = .11

fc! = !/c= (4#180000) (42.14)/"84142"

fc! = 1"3.4kg/cm2

f' = (0.8#) (8#00)/(7.2) (.11) (1"3.4)

f' = 10"0.1" 1182.04 = 12142.23kg/cm2


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4. DETERMINACIN DE LOSESFUERZOS PERMISIBLES EN ELACERO.

DATOS:

f'= 18"00kg/cm2 (;,a* 270)


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a) f'= G $% & t%!a*.

f' J 0."4 f'Tma, & m%, +a&,.

f' J 0.80 f'

f'= (0."4) (10#) = 1#101.10kg/cm2

f'= (0.80) (18"00) = 1#120.00kg/cm2


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b) f'i = G $% &a fa! %icia&.

f'i J 0.70 f'

f'i = (0.70) (18"00) = 13230 kg/cm2


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. COMPARACIN DE LOS ESFUERZOS.a) $% & t%!a* (', &a a'&icaci% *&

gat).

f'= 14327.0#kg/cm2 K f'= 1#101.10kg/cm2

Acta%t 5,mi!ib&

S ac'ta


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b) $% &a fa! i%icia& * t,a%!mi!i% % & c%t,

*& c&a,:

f'i= 1303.2#kg/cm2 L f'i= 13230.00kg/cm2

Acta%t 5,mi!ib& ! ac'ta

ta:Ob!,+a, %'fc (!f, % & c%c,t

*bi* a& '! ','i) ! a',Cima*am%t*& ,*% *& #H & '*,6a *!',cia,! ! ac'ta,6a% &! !f,! ca&c&a*!.


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c) $% &a fa! I%a& a& c%t, *& c&a,:

f'= 12142.23kg/cm2 K f'= 1#101.10 kg/cm2

Acta%t 5,mi!ib&

M

f'= 12142.23kg/cm2 K f'= 13230.00kg/cm2 Acta%t 5,mi!ib&.

M


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!. CAR"A DE A"RIETAMIENTO (#$%).S & &&ama ca,ga * ag,itami%t %

c%c,t ',!f,a* a a&&a ca,ga

i%c&%* & '! ','i * &a +iga %

cmbi%aci% c% &a f,a * ',!f,

',*c % !f, * t%!i% iga& a&

m*& * ,'t,a *& c%c,t.


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a) c,

= G

c,= m%t * ag,itami%t.

f,= *& * ,'t,a *& c%c,t.


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b)


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&. E'EMPLO

a) Dt,mi%a, & mm%t *

ag,itami%t = Gb) a ca,ga * ag,itami%t = G

c) a ca,ga S','!ta = G

*) $& fact, * !g,i*a* c%t,a &

ag,itami%t = G


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a) c,= G

kg-cm

kg-m


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b) >c,= G

(5a,a %a +iga !im'&m%t a'a*a)

* *%*:


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c) >!',= G

>!',= 4"17.8 201


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*)


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8. 9+i!i% ', ,!i!t%cia (


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A'f = (0.8#) (2#0) (1"0-30) # / 13"7.3 =

10.37 cm2

A'

= 1#.7" 10.37 = #.42 cm2

>' = (#.42) (13"7.3) / (30) (#) (2#0) =

0.1823

>'= 0.1823 J 0.3 V& = 0.30


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b) 9+i!i% !gP% c,it,i! *& A.

X% a +iga !,B !g,a.

! K X%

K

a +iga !,B i%!g,a.

X% K ! mB! ',bab& ! &a +iga

fa&&.

X% L 1.2 c, $& ,f, &%git*i%a& cm'&c% &! c,it,i! * a,ma*m6%im.


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!= G

!= >2/ 8 = (78 #70 1330) (20)2 / 8 C

100

!= 13340000.00 kg-cm

= G

= >2/ 8 = (1.2) (78 #70) (1.) (1330)U

(20)2 / 8 C 100

= 188000.00 kg-cm


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X%

14103800 kg-cm 188000 kg-cm

cm'&.

! K X% K

13340000.00 kg-cm K 14103800 kg-cm K

188000.00 kg-cm

Si cm'& =L a +iga !,B i%!g,a.

X%K !

14103800 kg-cm K 13340000 kg-cm

cm'&


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X% L 1.2 c,

14103800 kg-cm L 108128#.20 kg-cm

Si cm'& =L $& ,f, &%git*i%a& cm'& c%&! ,i!it! * a,ma* m6%im.

O5:

S ,cmi%*a c&ca, ac, * ,f, at%!i% 'a,a i%c,m%ta, & mm%t ,!i!t%t.


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c) Dt,mi%aci% *& fact, * !g,i*a*.

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esfuerzos permisibles en el concreto y en el acero

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