A 9-m high mechanically stabilized earth retaining wall with galvanized steel strip reinforcement in a granular backfill was constructed. Granular...

A 9-m high mechanically stabilized earth retaining wall with galvanized steel strip reinforcement in a granular backfill was constructed. Granular backfill has unit weight of 20 kN/m3 and c'=0 '=36º. Information about galvanized steel reinforcement: width of the strips 7.5 cm, vertical spacing 60 cm, horizontal spacing 90 cm, yield strength of strip 240 MPa, and soil-strip friction angle 20º, strip thickness 5 mm, strip length 12 m (constant strip length is used). Corrosion rate of galvanized steel strip is 0.025 mm/year and the life span of the structure is 50 years. The first strip is placed at 30 cm below the top of the wall, the lowest strip is placed at 30 cm above the base of the wall. a) Check whether the thickness and length of the strips are sufficient for satisfying factor of safety of 3.0 against tie break and pullout. If they are not sufficient, determine the new thickness and length to satisfy required F.S values. b) If you were to use different lengths of strips at different depths, calculate the lengths you would use for the 1st, 5th, 10th strips from the top of the wall.