Question

For a 25 cm thick cement concrete pavement, analysis of stresses gives the following values wheel load stress due to edge loading $25kg/c{m}^2,$ wheel load stress due to corner loading $30kg/c{m}^2,$ warping stress at corner region during summer $10kg/c{m}^2,$ warping stress at corner region during winter $9kg/c{m}^2,$ warping stress at edge region during summer $10kg/c{m}^2,$ warping stress at edge region during winter $7kg/c{m}^2,$ frictional stress during summer $5kg/c{m}^2,$ frictional stress during winter $3kg/c{m}^2.$ The most critical stress value for this pavement is _____$kg/c{m}^2$

• A. 40

Answer 1

The correct option is A 40
Thickness of cc pavement t = 25 cm

Wheel load stress due to edge loading
${\sigma }_e=25kg/c{m}^2$
Wheel load stress due to corner loading
${\sigma }_c=30kg/c{m}^2$
Warping stress at corner region during summer
${\sigma }_w=10kg/c{m}^2$
Warping stress at corner region during winter
${\sigma }_w=9kg/c{m}^2$
Warping stress at edge region during summer
${\sigma }_w=10kg/c{m}^2$
Warping stress at edge region during winter
${\sigma }_w=7kg/c{m}^2$
Frictional stress during summer
${\sigma }_f=5kg/c{m}^2$
Frictional stress during winter
${\sigma }_f=3kg/c{m}^2$
Critical Combination of stress -
(1) During summer, mid day (at edge)
${\sigma }_{\text{critical}}={\sigma }_e+{\sigma }_w-{\sigma }_f$
$=25+10-5$
$=30kg/c{m}^2$

(2) winter, mid-day (at edge)
${\sigma }_{\text{critical}}={\sigma }_e+{\sigma }_w+{\sigma }_f$
$=25+7+3$
$=35kg/c{m}^2$

(3) summer mid-night (at corner)
${\sigma }_{\text{critical}}={\sigma }_c+{\sigma }_w$
$=30+10$
$=40kg/c{m}^2$

(4) winter mid-night (at corner)
${\sigma }_{\text{critical}}={\sigma }_c+{\sigma }_w$
$=30+9$
$=39kg/c{m}^2$

$\text{Max (30, 35, 40, 39)}=40kg/c{m}^2$