Diseño De Cajon De Paso

UNIVERSIDAD DE LOS ANDES FACULTAD DE INGENIERIA POSTGRADO EN INGENIERIA ESTRUCTURAL MERIDA, EDO. MERIDA

REALIZADO POR: Ing. Israel A. Vergara CATEDRA: PUENTES PROFESOR: Ing. Rafael A. Torres Mérida, Noviembre 2006.

DATOS: · · · · · · 2 Trochas L=4m H=4m Hs = 2 m f’c = 250 kg/cm2 γ 3 s = 1920 kg/m

CALCULO DEL ESPESOR: · · tmin 0.06L = 0.06 x 4 0.24 m Norma AASHTO: é Lc + 3.05 ù é 4 +3.05 ù t min ³ 1.2 ê ú ³ 0.165m = 1.2 ê 30 ú ³ 0.28m ë 30 û ë û tmin = 28 cm Cartelas: L/25 = H/25 = 400/25 = 16 cm

·

OTROS PARAMETROS: · · · · Impacto, I: I = 0 ya que Hs > 2 pies, por lo tanto FI = 1 + I = 1 Sobrecarga Viva: HS20+20% P = 7258 + 0.2*7258 = 8709.60 kg Recubrimiento: 5 cm Altura útil: d = t – recub = 28 – 5 = 23 cm

PREDIMENSIONADO DE CAJON

0.16 m

0.16 m

0.28 m0.28 m

4m

0.16 m

0.28 m

Colocar 10 cm de concreto pobre f'c = 100 kg/cm2

CARGA PERMANENTE: Ws = Hs*γs = 2*1920 = 3840 kg/m2 Wpp = t*γc = 0.28*2500 = 700 kg/m2 Wcp = Ws + Wpp = 4540 kg/m2

Wcm = 4540 kg/m
0.16 m 0.28 m

4m

0.28 m

CARGA VARIABLE (2 trochas):

(5 .49 + 1 .75 Hs ) * 1 .75 Hs (5 .49 + 1 .75 * 2 ) * 1 .75 * 2 X = 1.75*Hs = 1.75*2 = 3.50 m < L entonces Wo Wv WoXé X ù 1107.21 * 3.50 é 3.50 ù 2 Wv = ê2 - L ú = ê2 - 4 ú = 1089.70kg / m L ë 4 û ë û Wcv = 1089.70 kg/m

Como Hs = 2m, Wo

=

4P

=

4 * 8709 .60

= 1107 .21kg / m 2

Wo = 1107.21 kg/m
0.16 m 0.28 m

Wv = 1089.70 kg/m
0.16 m 0.28 m

4m

0.28 m

4m

0.28 m

CARGA PERMANENTE: CASO 1: Presión Lateral = 30 pcf = 480 kg/m3

Wcm = 4540 kg/m
480*Hs = 960 kg/m2 480*Hs =960 kg/m2

4m

480*6.56 = 3148.80 kg/m2

3148.80 kg/m2 = 960+2188.80

2tH ö æ 2 Wi = 1920 Hs + 2500ç 2t + ÷ = 6468.07 kg / m L + 2t ø è

CARGA PERMANENTE: CASO 2: Presión Lateral = 60 pcf = 960 kg/m3

Wcm = 4540 kg/m
960*Hs = 1920 kg/m2
960*Hs = 1920 kg/m2

4m

960*6.56 = 6297.60 kg/m2

6297.60 kg/m2 = 1920+4377.60

2tH ö æ 2 Wi = 1920 Hs + 2500ç 2t + ÷ = 6468.07 kg / m L + 2tø è

CARGA VARIABLE: CASO 3:
æ 30 Pcf Coeficiente de Presión Lateral: Ka = 0.25 = ç ç 120 Pcf è ö ÷ ÷ ø

Tapa: Hs = 2 m en la carga superior Wcv = 1089.70 kg/m2 Fondo: Hs = 2 + 4 + 0.28*2 = 6.56 m en la carga inferior 8P 8 * 8709.60 Wcv = = = 260.69 Kg / m 2 (4.27 + 1.75Hs ) * (5.49 + 1.75Hs ) (4.27 + 1.75 * 6.56) * (5.49 + 1.75 * 6.56) (Wcv*Ka)sup = 1089.70*0.25 = 272.43 Kg/m2 (Wcv*Ka)inf =260.69*0.25 = 65.17 Kg/m2

Wcv = 1089.70 kg/m
272.43 272.43

4m

65.17

65.17

Wcv = 1089.70 kg/m

CARGA VARIABLE: CASO 4:
æ 60 Pcf Coeficiente de Presión Lateral: Ka = 0.50 = ç ç 120 Pcf è ö ÷ ÷ ø

Tapa: Hs = 2 m en la carga superior Wcv = 1089.70 kg/m2 Fondo: Hs = 2 + 4 + 0.28*2 = 6.56 m en la carga inferior 8P 8 * 8709.60 Wcv = = = 260.69 Kg / m 2 (4.27 + 1.75Hs ) * (5.49 +1.75Hs ) (4.27 + 1.75 * 6.56) * (5.49 + 1.75 * 6.56) (Wcv*Ka)sup = 1089.70*0.50 = 544.85 Kg/m2 (Wcv*Ka)inf = 260.69*0.50 = 130.35 Kg/m2

Wcv = 1089.70 kg/m
544.85 544.85

4m

130.35

130.35

Wcv = 1089.70 kg/m

ANALISIS ESTRUCTURAL: METODO DE RIGIDEZ:

[D ] = [K ]-1 {P } [D]4 X 4 = [K ]4 X 4 -1 {P }4 X 4

CARGAS EQUIVALENTES: {P

}

CARGA PERMANENTE: CASO 1:
WL2 4540 * 4.28 2= = 6930.46kg - m / m 12 12 WL2 6468.07 * 4.28 2 P34 = P43 = = = 9873.72kg - m / m 12 12 Wr L2 Wt L2 960 * 4.28 2 2188.80 * 4.28 2 P13 = P24 = + = + = 2801.98kg - m / m 12 30 12 30 W L2 W L2 960 * 4.28 2 2188.80 * 4.28 2 P31 = P42 = r + t = + = 3470.24kg - m / m 12 20 12 20 P12 = P21 =
6930.46
1

6930.46
2

2801.98

2801.98

3470.24
3

3470.24
4

é P11 ù é - 4128 .48 ù ê P ú ê4128 .48 ú ê 21 ú = ê ú kg - m / m ê P31 ú ê 6403 .48 ú ê ú ê ú P41 û ë - 6403 .48 û ë

9873.72

9873.72

CARGA PERMANENTE: CASO 2:
WL2 4540 * 4.28 2 = = 6930.46kg - m / m 12 12 WL2 6468.07 * 4.28 2 P34 = P43 = = = 9873.72kg - m / m 12 12 W L2 W L2 1920 * 4.28 2 4377.60 * 4.28 2 P13 = P24 = r + t = + = 5603.96kg - m / m 12 30 12 30 Wr L2 Wt L2 1920 * 4.28 2 4377.60 * 4.28 2 P31 = P42 = + =...