Situation
A temporary earth retaining wall consists of wooden plank driven vertically into the ground. The wall is designed to resist 2.4 m height of soil.
Given the following:
Cross-sectional dimensions of the plank = 300 mm wide × 75 mm thick
Allowable bending stress of the plank = 10.4 MPa
Allowable shear stress of the plank = 0.8 MPa
Unit weight of retained soil = 17.3 kN/m^{3}
Active earth pressure coefficient = 1/3
1. Calculate the maximum flexural stress.
A. 12.7 MPa |
C. 8.6 MPa |
B. 14.2 MPa |
D. 10.1 MPa |
2. Calculate the maximum shear stress.
A. 1.11 MPa |
C. 0.99 MPa |
B. 0.33 MPa |
D. 0.77 MPa |
3. Calculate the minimum thickness of the plank to prevent failure.
A. 90 mm |
C. 110 mm |
B. 80 mm |
D. 100 mm |