Types of sheet piles pdf

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types of sheet piles pdf
types of sheet piles pdf

SHEET-PILE WALLS ARE USED FOR

A sheet pile wall consists of a series of sheet piles driven side by side into the ground, thus forming a continuous vertical wall for the purpose of retaining an earth bank. They are commonly used for 

  1. water front structures, 
  2. temporary construction and 
  3. light weight construction where subsoil is poor for supporting a retaining wall. 

TYPES OF SHEET PILE WALLS PDF IS GIVEN AT BOTTOM

A sheet pile wall may be of three types 

  1. cantilever sheet piling 
  2. anchored sheet piling, 
  3. braced sheeting. 

Certain configurations of sheet piling are termed as bulkheads or cofferdams. A bulkhead is a sheet pile retaining wall of water front, backed up by ground. A cofferdam is a reasonably water-tight enclosure made of sheet pile walls, usually temporary, built around a working area for the purpose of excluding water during construction. Sheet pile walls are employed as bulkheads in piers, docks and harbours, and in sea walls, break waters, and other shore protection works. Fig. 21.1 shows various sheet-piling structure's.

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cantilever sheet piles
cantilever sheet piles
The sheet piles can be of timber, reinforced concrete or steel. Timber sheet piling is used for short spans, light lateral loads, and commonly for temporary structures in the form of braced sheeting. Wooden sheet piles may be considered permanent if they are permanently under water, or if they are impregnated with preservatives. Concrete sheet piles are precast members, usually with a tongue and groove joint, designed to withstand the permanent stresses during service and the handling stresses during construction. They are heavy and bulky, and require heavier equipment to drive and handle. Steel sheet piling is the most common type used because of the following advantages over other materials: 

anchored sheet pile
anchored sheet pile
  1. resistant to high driving stresses, 
  2. light weight, 
  3. can be used several times, 
  4. long service, 
  5. easier to increase the pile length 
  6. lesser deformation of joints when wedged full with soil and stones during driving.  

Factors affecting compaction of soil

CLASSIFICATION OF BULKHEADS 

A bulkhead is a sheet pile retaining wall of water front, backed up by ground. for dock and harbour structures. A bulkhead provides a vertical They are widely used wall so that ships may tie-up along side. A bulkhead may also serve as a pier. structure. which may jut out into the water. In contrast to the retaining walls, which are rigid bulky structures, bulkheads are flexible, generally composed of a single row of partially embedded sheet piles with major portion of the lateral support furnished externally. The upper and lower edges of bulkhead are practically fixed on account of the anchorage at the top and the passive resistance of the soil adjoining the lowest part of the bulkhead. The use of the anchor member tends to reduce the lateral deflection, the bending moment, and the depth of penetration of the pile. 

Bulkheads may be classified in the number of ways : 

  • according to mode of establishing the retaining system, 
  • according to structural type and loading scheme, 
  • according to sheet pile material, and 
  • according to end support.

Classification according to mode of establishing the retaining system. 

FILL AND DREDGED BULKHEADS
FILL AND DREDGED BULK HEADS

According to the mode of establishing the retaining system, bulkhead may be classified as 

  1. fill bulkhead 
  2. dredged bulkhead. 

A fill bulkhead is the one which is constructed in open water and then backfilled. If the bulk- head is constructed in natural ground (by driving) and then the earth removed from its face by dredging, it called dredged bulkhead 

Classification according to structural type and loading scheme. 

This is an important classification, according to which a bulkhead may be cantilever type or may be anchored. A cantilever bulkhead is the one which derives its stability entirely from the lateral resistance of the soil into which the sheet piling is driven. An anchored bulkhead is one which is held above its driven depth by one or more tie rods or anchors at or near its top. The stability of the cantilever bulkhead or sheet pile wall depends upon its embedment into soil below the dredged line. The stability of the anchored bulkhead depends more upon the anchors than on the inducement of large resultant earth pressure. 

sheet pile diagram
sheet pile diagram

Classification according to sheet pile material.

Depending upon the material of sheet pile, a bulkhead may be classified as flexible or rigid. A flexible bulkhead, generally constructed of steel piles, deflects and bends under the influence of a lateral force. Its stability depends upon the development of sufficient lateral resistance of soil adjacent to the embedded length of the bulkhead, and upon the anchor rods. A rigid bulkhead, constructed of reinforced concrete sheet pile derives its stability against lateral forces basically from its inherent structural strength. 

Classification according to condition of end support. 

According to this, bulkheads may be classified into two categories: 
  • bulkhead with free earth support, and 
  • bulkhead with fixed earth support. 

This classification applies only to anchored bulkheads. In the case of bulkhead with free earth support, the sheet piling is driven to a shallow depth only so that the deflection of the bulkhead is somewhat similar to that of a vertical elastic beam whose lower end is simply supported. In the case of bulkhead with fixed earth support the sheet piles are driven depth so that lower end of the bulkhead ie fixed in position.

Forces acting on a bulkhead.

A number of forces are known to be acting over a bulkhead, some of which are constantly in play while others come in effect only occasionally and intermittently. A sheet pile wall or bulkhead may be subjected to some or all of the following types of lateral pressures : 

  1. active and passive earth pressures, 
  2. lateral pressure due to surcharge load,
  3. unbalanced water pressure and seepage pressure
  4. mooring pull, ship impact etc. 
  5. earth-quake forces. 

The classical earth pressure theories of Rankine or Coulomb, which are based on the condition of full mobilization of the shear strength of soil due to yielding of the wall laterally by sliding or by rotation about its bottom, do not apply in the case of bulkheads where the deformation conditions are different. The earth pressure against sheet pile wall can be determined by theories which take into account the conditions of yield of the wall (Hansen, J.Brinch, 1953). In practice, several empirical and semi-empirical methods have been developed all of which use the classical earth pressure theories.

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