CLI AccropodeII concrete armour units.pptx

breakwater armour accropode

1. 1 Design, Physical Modeling and Implementation of Accropode Single Layer Armour Sahel Omid Iranian (SOI)  May 2023

2. 2 Design

3. Could be Constructed with limited equipment , resources and professional skills Repair works can be easily executed Owing to their flexibility Not sensitive to differential settlements 3 Benefits of Rubble Mound Breakwaters

4. Why did Concrete Armour layers were selected? 1) sometimes we need Larger armour stones It is impossible to find or produce Rubble mound breakwaters Are mostly built of quarried rocks 2) In south of Iran , there is a lack of pure and good rock quarries Economically Cannot be produced and transported 4 Due to larger wave loads or severe design conditions

5. 5 Uniformly Placed Randomly placed Placement Single Layer Double Layer Number of layers Friction Interlocking Own Weight & Interlocking Own Weight Stability Factor Cob (1969) Accopode (1980) Tetrapode (1950) Cube Armour Diahitis (1998) Core- loc (1996) Akmon (1962) Modified Cube (1959) Seabee (1978) A-Jack (1998) Tribar (1958) Antifer Cube (1973) Shed (1982) Xbloc (2003) Stabit (1961) Haro (1984) Dolos (1963) Tripod (1962)

6. A) The water depth is high , so high volume of work B) In a harsh environment , underwater placement will be quite difficult 2) When there are correct alternatives , the opinion of designer is completely important Will be used mostly for revetments friction type armour is not recommended for exposed breakwaters Uniformly placed armour units 6 Why Accropode Armour Units

7. Shed Armouring at Burj al Arab Hotel, Dubai, UAE 7

8. 8 Side view of armour facing

9. Randomly Placed Armour – single layer armouring Single layer randomly placed armour units have been applied since 1980. The Accropode was the first block of this new generation of armour units and became the leading armour unit worldwide for the next 20 years. Core- loc (1994) and Xbloc (2003) are further examples of this type of armour unit. hydraulic stability will be provided by interlocking and structural strength The Accropode 9

10. Single layer armour units: Accropode™ (6.2 m3, Scarborough, UK), Core-loc® (15 m3, Kaumalapau Harbor, Hawaii) and Xbloc (4 m3, Port Oriel, Ireland) 10

11. The required armour unit size ( Dn ) can be assessed by a stability formula. T he Hudson formula Single layer armouring is generally designed for no damage Admittedly, even low damage levels of 0–5% are not accepted. 11   = ( )  

12. 12 In order to guaranty the functioning of the armour layer even during a design storm, the Accropode has a relatively large safety margin . The armour layer should be further able to withstand an overload of about 20% (design wave height exceeded by 20%) without significant damage.

13. 13 Stability of concrete armour layers (randomly placed blocks)

14. 14 Geometric characteristics of concrete armour layers

15. 15 Basic design formulae for randomly placed armour layers

16. 16 Definition of parameters

17. The proposed stability formula bear significant uncertainties ( standard deviations for of about 20% for Accropode)   17 Empirical coefficients of stability formula for concrete breakwater armour units (van der Meer (1988))

18. Characteristic damage levels for various types of concrete armour units (CEM, 2003) Damage number N od : Number of displaced armour units within a strip of breakwater slope of width D n (nominal diameter of armour units); Damage number N d : Number of displaced armour units referred to the total number of armour units placed within a certain range from design water level (a range of ±1.5 H D (design wave height) is typically considered). 18 Typical values of Nod and Nd for certain damage levels

19. Physical modeling 19

20. The main purposes of carrying out physical model tests of the concrete armour breakwater are as follows: Investigating the hydraulic stability of the armor layer on the sea side under design wave conditions Investigating the overtopping rate to ensure the adequacy of the crest level and ensure the desired operating conditions Ensuring the stability of the toe in different circumstances of water level 20

21. A condition for perfect simulation is that the model shall be geometrically similar to the prototype. Scale factor:   By setting the stability number of prototype and model equal , the relationship can be written as follows: , , ,   21 According to the nominal dimeter of the Accropode units of different sections of the prototype and the desired Accropode units for the physical model , the scale factor for the sections has been calculated.

22. W5 Unit Parameter   14.04 ton W p Prototype 5.11 m Hs 9 s Tp 1.817 m D p 2.34 t/m 3 ρ sp 1.025 t/m 3 ρ wp 1.28 - Δp 96.500 gr W m Model 10.43 cm Hs 1.29 s Tp 3.46 cm D m 2.34 gr/cm 3 ρ sm 1 gr/cm 3 ρ wm 1.34 - Δm 50.36 Λ Scale 22 How to practically calculate scale factor

23. Implementation 23

24. 24 Note Limit Title ASTM C 535 <35% Abrasion strength (Los Angeles) ASTM C 88 < 12% Soundness test ASTM D 2166 >35 MPA Unconfined compression - Minimum density L=largest dimension (length) G= Largest dimension measured perpendicular to L E= largest dimension measured perpendicular to LG Ratio of dimensions The water absorption capacity of the rock fill <3% Porosity W is the weight of Accropode unit unit weight of natural rocks Note Limit Title ASTM C 535 <35% Abrasion strength (Los Angeles) ASTM C 88 < 12% Soundness test ASTM D 2166 >35 MPA Unconfined compression - Minimum density L=largest dimension (length) G= Largest dimension measured perpendicular to L E= largest dimension measured perpendicular to LG Ratio of dimensions The water absorption capacity of the rock fill <3% Porosity W is the weight of Accropode unit unit weight of natural rocks Quality of underlayer rockfill

25. 25 Note Value title H: The height of the Accropode unit (In the case of local DEFECTS) Vertical tolerance (In the case of general profiles ) Vertical tolerance In relation to theoretical profile Slope bottom Note Value title H: The height of the Accropode unit (In the case of local DEFECTS) Vertical tolerance (In the case of general profiles ) Vertical tolerance In relation to theoretical profile Slope bottom The mound must be sufficiently regular to prevent any Accropode unit from being “out of profile”, but sufficiently rough to avoid abnormal slipping due to the settlement. Measurements must be made on the slope profile at least every H meters . Tolerance Concerning Filter Layer and Toe Mound Profiles

26. 26 Local DEFECTS may be measured by cross-sections no more than 10 m apart with a measurement point every H meters, associated with visual inspection between profiles. Generalized Profile errors are determined on the basis of the η i measurement points used for local DEFECTS by means of the following formula: is the absolute value of the local DEFECT measured in an area between cross-sections spaced no more than 20 m apart.   Measurement Methods

27. 27 Positioning Drawings Drawings must be on the basis of surveys of the under-layer provided by the contractor. Drawings shall indicate the x and y coordinates to be used for the center of gravity of each unit to be placed under and above water. Drawings must be prepared in accordance with placing principles and complied with: The horizontal mesh or interval between the centers of gravity of two units in the same row = M1 The mesh in the direction of slope or interval between the centers of gravity of two units in two consecutive rows in the plane of the slope = M2 On the roundhead and bends, the maximum horizontal mesh at the first row of units = M3 Placing Accropode Units

28. 28 Basic Principles for placing units A. The Following principles must be followed. If not, the units concerned will have to be repositioned. Units are to be placed in a single layer and each unit in contact with the under-layer. Each unit is keyed between two units in the row below and the basic mesh is a lozenge . A triangular and pentagonal mesh may be used in special cases and is shown on the placing drawings. Two adjacent units must not be, in general, in contact at anvil face level . It is to be avoided to place units with the center line of their nose orthogonal to the slope. The overall placing density must be within 95% of the theoretical density. Placing Accropode Units

29. 29 Basic Principles for placing units B. The Following principles must be followed. Isolated DEFECTS will be examined on a case-by-case basis; repeated DEFECTS in a group of units cannot be examined and the units in the area of the DEFECT have to be repositioned. Less than 1/3 of the units must have the anvil parallel to the slope . Units in this attitude must be distributed over the armour and not grouped together. The Units to be placed have reached the specified strength. In the absence of any risk of storms, a compressive strength of at least 30 Mpa measured on a sclerometer will be acceptable for units less than 16 m3 placed above water. Placing Accropode Units

30. 30 Slinging (to placing units in varied attitudes) Use as short a sling as possible ( for guidance, the length should be between 2.15 and 2.2 times the height of the unit ). The exact length must be defined for each type of unit depending on the type of sling used. The sling must not be too short in order to vary placing attitudes as much as possible and not too long so that it allows the unit scape. Use two type of slinging alternately . (Passing under the upper anvil alone or under the upper anvil and a nose). Placing Accropode Units

31. 31 Placing trial A trial placing shall take place before start of actual location placing. The test can be done on an existing slope (3/2 of 4/3) or on a prepared slope if possible with actual size under-layer rocks. At least 15 units of each size must be used . The placing mesh should be achieved ( using the anticipated crane equipment, operatives, etc. which may be aided by marking the theoretical positions on the slope) Placing Accropode Units

32. Units are individually placed 32

33. Typical Accropode Armour Toe 33

34. 34 Accro pode reinforced type of toe

35. 35 Accro pode rock mound type of toe

36. 36 Accro pode standard toe

37. 37 Rock excavated type of toe

38. 38 Under layer placement example

39. Phasing of Placing W orks 39

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43. From sea 43

44. Varied slinging method 44

45. 45 Varied slinging method

46. 46 Two slinging method

47. Supplying units to the crane for placement Finishing a placement of a roundhead using a floating crane 47

48. Roundhead under construction 48

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