L20,L21,L22,L23,L24,L25 sheet piling

Enter the sheet piling defined surface level at the passive side: the level of the resisting soil is lowered below the expected level by an amount equal to the Increase L20 retaining height percentage of the distance between the lowest support and the excavation level, limited to a maximum (i.e.Maximum increase retaining height). The designer should weigh the risk of impact and resulting damage as it applies to his situation.Vinyl and fiber reinforced polymer—L20 and L21 or L22 should be limited to half the yield stress of the material. Enter the user defined change in height applied to the phreatic line level on the passive side. If conditions require the inclusion of either of these boat impact forces in the design, they should be evaluated based on the energy to be absorbed by the wall. Raise in phreatic line on active side Enter the user defined increase in height applied to the phreatic line level on the active side. Anchor design—L21 Anchors may consist of concrete, steel member, or sheet pile deadmen attached to the pile with tie rods, tiebacks with grouted anchors, or various configurations of steel or concrete piles attached to the sheet pile by a wale or through a tie rod. Enter the user defined partial factor applied to the soil properties:

The magnitude and location of the force transmitted to the L 20 and L 21 wall will depend on the vessel’s mass, approach velocity, and approach angle. Enter the user defined partial factor on base resistance L 25 applied on the characteristic value of the base resistance of the ground Rb;k to get the design value of the base resistance Rb;d (Equation 33.1):The purpose of the mandrel is to support the vinyl pile only during driving. Military Handbook 1025/1 (Department of the Navy 1987) provides excellent guidance in this area. Design of anchors and tie rods is described in Design of L22 Sheet Pile Walls (USACE 1994c).This input is available only if the Check vertical balance check-box was enabled in the Model window. Lateral loads applied by a moored ship are dependent on the shape and orientation of the vessel, the wind pressure, and currents applied.

Due to the use of strong synthetic lines, L23,L24 and L25 can be developed. Piling—Cold-rolled steel sheet pile sections have a weaker interlock than hot-rolled sections and may unlock while being driven in hard conditions, resulting in misalignment. Click this button to reset all values to the default values prescribed in the Dutch Annex of the Eurocode 7. A temporary guide structure or template is recommended to ensure that the L23 piles are driven in the correct alignment Therefore, it is recommended that mooring devices be designed independent of the sheet pile wall. The default values prescribed by the Dutch Annex of the L 24 are written at the left of each input area of the User Defined Partial Factors window. If modified, the value appears in red color.

A steel sheet pile thickness of a fourth inch is typically recommended for driveability. In tough driving conditions, such as dense to very dense sands, very stiff to hard clay soils, or soils containing significant amounts of gravel, a thicker L24 pile should be considered. Ice can affect marine-type structures in many ways. The default values prescribed by the Dutch Annex of the Eurocode 7 for L 22 and L 23 correspond to those of safety classes respectively II and III of the CUR recommendations, except for the factor on driving moment in case of overall stability. Access for a crane is often required to operate the hammer. Short piles or piles in easier driving conditions may be installed with a backhoe or hammer attached to a back/track hoe.

Typically, L 22 and L 23 lateral pressures are caused by impact of large floating ice masses or by expansion upon freezing. For background information on the Dutch Annex of the EuroCode, see section 35.2. In areas where corrosion of the steel pile is a concern, a thicker pile than required structurally should be considered to allow for corrosion throughout the design life. Note: Note: 4.1.2.3 Eurocode 7 – Belgian Annex In this window the defaults partial factors prescribed in the Belgian Annex NBNEN 1997-1 ANB of the Eurocode 7 are given and can be modified by the user. Equipment—Sheet pile is typically installed by driving, jetting, or trenching. Jetting is often not allowed for walls designed to retain soil. Expansive lateral pressures induced by water freezing in the backfill can be avoided by backfilling with a clean free-draining sand or gravel or installation of a drainage collector system. Hammers for driving may be steam, air, diesel-drop, single action, double action, differential action, or vibratory. EM 1110-2- 1612 should be references when the design is to include ice forces.Vibratory hammers work well in sand, silt, or softer clay soils. Harder driving conditions such as stiff clay may require an L20 and L21 impact hammer.

Those L 24 and L 25 partial factors are used for the following verification methods according to EC7 B: In its national annex, Belgium selected Design Approach 1. Therefore, verification is performed only for the two combinations of DA1: set 1 and set 2.Use of a protective cap is required with impact hammers. Protective shoes may be used on the tip of a pile in hard driving conditions. When driving L25 pile in stiff clays or dense sands, a steel mandrel is often driven with the vinyl pile and extracted upon completion of driving.