DISEO DE VIGA PRINCIPAL 25X45 (b*h)

DATOS

h = 45 cm Peralte de la viga

b = 25 cm Base de la viga

L = 3.40 m Long. De viga entre eje

d = 39 cm Peralte efectivo

d'= 6 cm d=39cm

MOMENTO ULTIMO(calculo primera parte del trabajo) h=45cm

Mu(+)= 11.526 Tn-m Mu(-)= 16.822 Tn-m

Mu(+)= 1.482 Tn-m Mu(-)= 17.686 Tn-m

Mu(+)= 10.300 Tn-m

ESPECIFICACIONES

f'c = 210 Kgr/cm2 Esfuerzo ala compresion del concreto b=25cm

fy = 4200 Kgr/cm2 Esfuerzo de fluencia del acero

DIAGRAMA DE MOMENTO DE LA VIGA A DISEAR DATO ANLISIS (Kg-m)

As=?r

d'As'=?

PARA EL EJEMPLO SE TOMARA LA VIGA 9-15

VERIFICACIN DE CUANTIAS

CUANTIA MAXIMA

0.85 x 0.85 x 210 x 0.59 = 0.0214

4200

0.75 x 0.0214187 = 0.0161

CANTIDA DE ACERO MAXIMO

0.0161 x 25 x 39 = 15.66 cm2

ACERO MINIMO

14x 25 x 39 =3.25 cm2

4200

0.7 x 210 x 25.0 x 39. = 2.35 cm2

4200

CALCULO DE LAS AREAS DE ACERO

ACERO POSITIVO MU(+)

= 11.53 Tn-m

POR TANTEO

primer tanteo con a = 6.00 cm

11.53 = 8.47 cm2 8.47 x 4200 = 7.97 cm

0.9 x 4200 x 36.00 0.85x210 x 25.

segundo tanteo a = 7.97 cm

11.53 = 8.71 cm2 8.71 x 4200 = 8.20 cm

0.9 x 4200 x 35 0.85x210 x 25

tercer tanteo a = 8.20 cm

11.53 = 8.74 cm2 8.74 x 4200 = 8.22 cm

0.9 x 4200 x 35 0.85x210 x 25

cuarto tanteo a = 8.22 cm

11.53 = 8.74 cm2 8.74 x 4200 = 8.23 cm

0.9 x 4200 x 35 0.85x210 x 25

quinto tanteo a = 8.23 cm

11.53 = 8.74 cm2 8.74 x 4200 = 8.23 cm

0.9 x 4200 x 35 0.85x210 x 25

sexto tanteo a = 8.23 cm

11.53 = 8.74 cm2 8.74 x 4200 = 8.23 cm

0.9 x 4200 x 35 0.85x210 x 25

SE DEBE VERIFICAR

Asmax > As

15.66 > 8.74 cm2 NO REQUIRE ACERO EN COMPRESION

As(+)

= 8.74 cm2

2 5/8'' + 2 3/4'' =9.66 cm2 ..........Ok

dbAs maxmax

fyfy

cfb

6117

6117'85.0 1

bMAX 75.0

2

adfy

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As14

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ACERO POSITIVO MU(+)

= 1.48 Tn-m

ACERO MINIMO

14x 25 x 39 =3.25 cm2

4200

3.25 x 4200 = 3.06 cm

0.85 x 210 x 25.

0.9x3.25 x 4200 x 37.47 = 4.60 Tn-m

Entonces para este caso se asumira acero minimo ya que el momento minimo es mayor al mometo a disear

Mu > Mu(min)

1.48 < 4.60 Tn-m DISEE CON ACERO MINIMO..........Ok

As(+)

= 3.25 cm2

2 3/4'' + 0 0 '' =5.70 cm2 ..........Ok

ACERO POSITIVO MU(+)

= 10.30 Tn-m

POR TANTEO

primer tanteo con a = 10.00 cm

10.30 = 8.01 cm2 8.01 x 4200 = 7.54 cm

0.9 x 4200 x 34.00 0.85x210 x 25.

segundo tanteo a = 7.54 cm

10.30 = 7.73 cm2 7.73 x 4200 = 7.28 cm

0.9 x 4200 x 35.23 0.85x210 x 25.

tercer tanteo a = 7.28 cm

10.30 = 7.71 cm2 7.71 x 4200 = 7.25 cm

0.9 x 4200 x 35.36 0.85x210 x 25.

cuarto tanteo a = 7.25 cm

10.30 = 7.70 cm2 7.70 x 4200 = 7.25 cm

0.9 x 4200 x 35.37 0.85x210 x 25.

quinto tanteo a = 7.25 cm

10.30 = 7.70 cm2 7.70 x 4200 = 7.25 cm

0.9 x 4200 x 35.38 0.85x210 x 25.

sexto tanteo a = 7.25 cm

10.30 = 7.70 cm2 7.70 x 4200 = 7.25 cm

0.9 x 4200 x 35.38 0.85x210 x 25.

septimo tanteo a = 7.25 cm

10.30 = 7.70 cm2 7.70 x 4200 = 7.25 cm

0.9 x 4200 x 35.38 0.85x210 x 25.

SE DEBE VERIFICAR

Asmax > As

15.66 > 7.70 cm2 NO REQUIRE ACERO EN COMPRESION

As(+)

= 7.70 cm2

2 5/8'' + 2 5/8'' =7.92 cm2 ..........Ok

2

adfy

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mina

dfyAscMU

ACERO NEGATIVO MU(-)

= 16.82 Tn-m

POR TANTEO

primer tanteo con a = 10.00 cm

16.82 = 13.09 cm2 13.09 x 4200 = 12.32 cm

0.9 x 4200 x 34.00 0.85x210 x 25.

segundo tanteo a = 12.32 cm

16.82 = 13.55 cm2 13.55 x 4200 = 12.75 cm

0.9 x 4200 x 33 0.85x210 x 25

tercer tanteo a = 12.75 cm

16.82 = 13.64 cm2 13.64 x 4200 = 12.84 cm

0.9 x 4200 x 33 0.85x210 x 25

cuarto tanteo a = 12.84 cm

16.82 = 13.66 cm2 13.66 x 4200 = 12.86 cm

0.9 x 4200 x 33 0.85x210 x 25

quinto tanteo a = 12.86 cm

16.82 = 13.66 cm2 13.66 x 4200 = 12.86 cm

0.9 x 4200 x 33 0.85x210 x 25

sexto tanteo a = 12.86 cm

16.82 = 13.66 cm2 13.66 x 4200 = 12.86 cm

0.9 x 4200 x 33 0.85x210 x 25

SE DEBE VERIFICAR

Asmax > As

15.66 > 13.66 cm2 NO REQUIRE ACERO EN COMPRESION

As(-)

= 13.66 cm2

2 3/4'' + 3 3/4'' =14.25 cm2 ..........Ok

ACERO NEGATIVO MU(-)

= 17.69 Tn-m

POR TANTEO

primer tanteo con a = 10.00 cm

17.69 = 13.76 cm2 13.76 x 4200 = 12.95 cm

0.9 x 4200 x 34.00 0.85x210 x 25.

segundo tanteo a = 12.95 cm

17.69 = 14.39 cm2 14.39 x 4200 = 13.54 cm

0.9 x 4200 x 33 0.85x210 x 25

tercer tanteo a = 13.54 cm

17.69 = 14.52 cm2 14.52 x 4200 = 13.66 cm

0.9 x 4200 x 32 0.85x210 x 25

cuarto tanteo a = 13.66 cm

17.69 = 14.54 cm2 14.54 x 4200 = 13.69 cm

0.9 x 4200 x 32 0.85x210 x 25

quinto tanteo a = 13.69 cm

17.69 = 14.55 cm2 14.55 x 4200 = 13.69 cm

0.9 x 4200 x 32 0.85x210 x 25

dbAS ''dbA S MAX 55.0'

2

adfy

MuAs

2

adfy

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bfc

fyAsa

'85.0

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'85.0

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'85.0

sexto tanteo a = 13.69 cm

17.69 = 14.55 cm2 14.55 x 4200 = 13.70 cm

0.9 x 4200 x 32 0.85x210 x 25

SE DEBE VERIFICAR

Asmax > As

15.66 > 14.55 cm2 NO REQUIRE ACERO EN COMPRESION

As(-)

= 14.55 cm2

2 3/4'' + 3 3/4'' =14.25 cm2 ..........Ok

9 15

3.40m

3 3/4'' 3 3/4''

3 3/4''

0.90m 0.90m

2 5/8''

2 3/4'' 2 3/4''

POR PROCESO CONSTRUCTIVO SE UTILIZARA

2 3/4'' + 3 3/4'' 3 3/4'' + 2 3/4'' + 3 3/4''

0.45m 0.45m 0.45m

O

0.25m 0.25m 0.25m

2 5/8'' + 2 3/4'' 2 5/8'' + 2 5/8'' + 2 3/4''

SECCION A - A SECCION B - B SECCION C - C

A

A

B

B

C

C

2

adfy

MuAs

2

adfy

MuAs

bfc

fyAsa

'85.0