materiales construccion






TRABAJO DE RESISTENCIA




Juan David Noriega
Jose Miguel Arciniegas
Sergio Galvis


Para: Ing. Viviana Perez






1).

3 kN2KN 5 KN

| 1 1 | 1 1 |

ΣFy = 0ΣMB= 0
-3+RA-2+RB-5 = 0 (3*3)-(RA*2)+(2*1)-(5*1)= 0
RA+RB = 10 9 - 2RA + 2-5= 0
2RA= -5+2+9RA= 3KN
RB=7KN

Corte 1
3kN
o M
| x v
ΣFy = 0 ΣMo= 0
-3-V= 0 (3)(x)+M = 0
V=3 M= 3x




Corte 2

3KN
ov M
| x |

ΣFy = 0 ΣMo = 0
-3+3-V=03x-(3x-1)+M= 0
V=0 3x-3x+3+M=0
M = -3
Corte 3

3kN 2kN
o V M
3kN (x-2)
x
ΣFy = 0 ΣMo = 0
-3+ 3- 2- V= 0 (3x)-(3x-1)+(2x-2)+M= 0
V= -2 3x-3x+3+2X-4+M=0
M= -2x+1Corte 4


3KN 2KN V

1 3KN 1 1 7KN (x-3)
X

ΣFy = 0 ΣMo = 0
-3+3-2+7-V=0 (3*X)-(3* X-1)+(2*X-2)-(7* X-3)+M =0
V= 5 M + 3X- 3X+ 3+ 2X- 4- 7X+ 21=0
M=5X-20



+
V (kN)
- -











-








10.57

9.43



 
A [mm2]
y´
(A)(y´)
I
Dy2
(A)( Dy2)

1
100
17.5
1750
208.333
8.072
6512.49

2
100
101000
833.333
0.572
32.49

3
125
2.5
312.5
260.416
6.932
6003.1125

 
325
 
3062.5
1302.082
 
12548.0925











Y=Σ A*Y/ Σ A
Y= 3062.5 mm2 / 325 mm2 = 9.43
I = ΣI + (A* Dy ¨2)
I = 1302.07+ 12548.0925 = 13850.1625 mm4





2)


 
A mm2
Y
A Y
I
Dy2
ADy2mm4
1
150
27.5
4125
312.5
13.752
28359.375
2
150
17.5
2625
2812.5
3.7522109.375
3
300
5
1500
2500
8.752
22968.75

600

8250
5625

53437.5

y=Ir= 59062.5mm4 = 5.91*10-8 m4
Conversión de unidades.
4 Klb/pulg

1574.8 N/m
8 Klb/ pulg

3149.6 N/m4)
r=1pie

 
A mm2
Y
A Y
I
Dy2
ADy2mm4
1

1


0
0
∑





0

y= Ir= ft4 =16.29*103pulg4
Unidades.
12...