The traditional earth pressure distribution method is used to calculate the direct web piles. The traditional earth pressure distribution method is used to calculate the direct web piles without considering the anchor displacement or recalculating the straight web piles. The anchor displacement or the redistribution of earth pressure are not considered. The calculated maximum bending moment of hot-rolled steel sheet pile can be reduced by 1/3 or multiplied by 0.7-0.8 reduction factor. The results can be used as the standard value of bending moment of sheet pile cofferdam.
However, it is not allowed to reduce in the following cases: (1) Straight mesh sheet pile manufacturers do not have tie rods; or weak anchorage of tie rods may lead to displacement, while the foot of the pile is built in the soil; in this case, no redistribution of earth pressure will occur; (2) loose clay behind the wall; (3) the soil wall behind the wall does not reach the height of the anchor rod; (4) hot-rolled steel sheet piles from the harbour pond to the anchoring system. The soil behind is backfill; (5) reinforced concrete sheet pile wall with high stiffness
The so-called reinforced concrete sheet pile wall with high stiffness should have stiffness n > 0.06 per linear meter. In this case, sheet pile wall should be calculated as a free end supporting beam, and the bending moment of sheet pile can not be reduced. If n is less than 0.06, it is suggested that sheet-pile walls should be regarded as flexible walls, and that they have been constructed underground or semi-constructed. The stiffness of each linear meter is given by the following formula:
PS straight mesh sheet piles are usually used in cofferdams in the United States.