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Unformatted text preview: 05Ch05.qxd 9/25/08 484 2:29 PM Page 484 CHAPTER 5 Stresses in Beams (Basic Topics) Problem 5.12-11 A plain concrete wall (i.e., a wall with no steel
reinforcement) rests on a secure foundation and serves as a small
dam on a creek (see figure). The height of the wall is h 6.0 ft
and the thickness of the wall is t 1.0 ft. t (a) Determine the maximum tensile and compressive stresses st and
sc, respectively, at the base of the wall when the water level reaches the
top (d h). Assume plain concrete has weight density gc 145 Ib/ft3.
(b) Determine the maximum permissible depth dmax of the water if
there is to be no tension in the concrete. Solution 5.12-11 t STRESSES AT THE BASE OF THE WALL
(d DEPTH OF WATER) height of wall
thickness of wall
width of wall (perpendicular to the figure) gc
gw weight density of water st W
S hgc + sc W
A hgc width density of concrete d d Concrete wall h
b h M
S d 3gw Eq.(2) t2 depth of water
(a) STRESSES AT THE BASE WHEN d W weight of wall W bhtgc h 6.0 ft 72 in. d F resultant force for the water pressure t 1.0 ft 12 in. MAXIMUM WATER PRESSURE = gw d
F Eq. (1) t2
d 3gw 1
(d)(gw d) (b)
2 M d
3 A bt S 13
2 gc 145 lb/ft3 gw 62.4 Ib/ft3 72 in. 145
1728 h ...
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This note was uploaded on 12/22/2011 for the course MEEG 310 taught by Professor Staff during the Fall '11 term at University of Delaware.
- Fall '11