A presentation on Reinforced Soil Structure

About RE Wall construction.

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2. 2 2 Leader in Soils , Structures , and Nuclear The Origin… COMPANY’S BRIEF INTRODUCTION

3. GLOBAL NETWORK Present in 80 countries. Projects worldwide. Indian Operation: Started in 1997 ISO9001, ISO45001 Head office of Asia 250+ employees Completed 4 Million SqM RE Wall Global Operation : Started in 1968 Present in 80 countries 1,200 employees TO = € 270 Mio Henri Vidal Inventor of Reinforced Earth®

4. BUSINESS LINES

5. Reinforced Earth ® Structure - Typical Details® ReinforcedEarth ® structures combine selected granular, engineered backfill with steel or synthetic tensile reinforcements and a modular facing system. This ideal combination creates a durable, mass gravity retaining wall. Facia Panel Reinforced Fill Geosynthetic reinforcements

6. ABOUT THE PROJECT The Gwarko flyover will connect B & B Hospital area through Gwarko Chowk to Balkumari of Lalitpur stretch of the valley ring road in Nepal. The flyover will be built using the grade separation method under which a junction of two or more surface transport axes at different heights (grades) are aligned so that there will be no disruption in traffic flow on other transit routes when they cross each other. The approaches of the flyover are to be constructed with Reinforced Earth wall technology with cruciform shaped concrete panels and geosynthetic polymeric straps. The stretch length of the reinforced earth wall is around 560m. 6

7. ABOUT THE PROJECT STAKEHOLDERS Project Title: Construction of Reinforced Earth ® Wall Structure at Gwarko Flyover Project Location: Nepal Description: Reinforced Earth ® Wall as Bridge Approach Structure Client: Department of Road, Nepal Main Contractor: Ashish/Samanant/Religare JV Consultant: Geocom -BDA- Ray’S JV Specialist Contractor & Local Partner : Terre Armee India & Marron Trading Nepal Design Standards: BS:8006:2010, AFNOR NF-P 270-94, IRC SP 102:2014 Design Life: 100 years 7

8. ABOUT THE PROJECT Plan View of Reinforced Earth Structure

9. ABOUT THE PROJECT Typical C/S of Reinforced earth Structure

10. ADVANTAGES OF PROPOSED RE WALL OVER CONVENTIONAL RCC RETAINING WALL FLEXIBILITY PERFORMANCE AGAINST SEISMIC FORCES CONSTRUCTIBILITY EXECUTION TIME. INVOLVEMENT OF MACHINERY AND COST

11. The inter-placing of selected soil and reinforcements develops friction at the points of contact between the two, resulting in a permanent and predictable bond and creating a unique composite construction material called “Reinforced Earth". DESIGN OF RE WALL - PRINCIPLE OF SOIL REINFORCEMENT

12. DESIGN OF RE WALL - POINTS TO REMEMBER Design of Reinforced Earth wall is performed in accordance with relevant clauses/ sections of standards - BS:8006:2010, AFNOR NF-P 270-94, IRC SP 102:2014 The above stated standards covers various aspects as stated below: Materials & its properties Type of reinforcement Facing elements Design methods Partial factors Various stability checks Construction methodology

13. DESIGN CONSIDERATIONS Materials & its properties Seismic Co-efficient = 0.36g

14. GeoStrap ® - Geosynthetic Reinforcement High tenacity polyester fibres LLDPE sheath Width - 50 mm Details of Polymeric Reinforcements Properties Test Method Unit   Minimum average roll value Ultimate Tensile Strength ASTM D6637 kN 25 30 40 50 60 65 Width   mm 49 49 49 49 49 49 Long Term Design Strength   kN 14.8 18.0 23.77 30.0 35.6 39. Long Term Design Strength (considering ramification factor of 1.1)   kN 13.5 16.37 21.61 27.29 32.4 35.4

15. Design Methods BS 8006 : 2010 Design is based on Ultimate limit state method AFNOR NF-P-220-94 Design is based on Ultimate limit state method IRC SP 102:2014 Design is based on ultimate limit state, based on various codes such as BS 8006, FHWA & AFNOR

16. DESIGN-CONSIDERATION AS PER CODAL PROVISIONS Recommendations for Reinforced Earth fill

17. Details of Concrete Panels 2m wide 1.6m Height

18. Details of Connector 3D View of Geocore Connector The patented mechanical connection between the facing panels and the soil reinforcement is partially cast into the precast concrete facing panel. These connectors contains a recess through which polymeric strap is threaded into and thus, fitted to the facing panel on the jobsite.

19. DESIGN PRINCIPLE RECOMMENDATION BY BS8006/IRC SP102:2014 The design is based upon the principle given in BS 8006-2010 “Code of Practice for Reinforced Soils and other fills” published by the British Standard . In common with other codes for the design of civil engineering structures, this code of practice adopts limit state principles. These principles involve the application of partial material factors for various materials, load factors for various load types, design lives and load combinations to ensure sufficient safety margins

20. DESIGN CHECKS The design of reinforced soil structure is undertaken in two parts: EXTERNAL STABILITY Overturning of the reinforced soil block Forward sliding of the structure on the foundation soil Bearing failure of foundation soil Slip failure of retained and foundation soil. INTERNAL STABILITY Tensile rupture at any point along the length of the reinforcement Loss of frictional bond (adherence) between the reinforcement and the soil fill .

21. Construction Methods

22. Setting up of the Precasting Yard

23. Setting up of Pre-casting Yard The following facilities shall be set up in order to implement the casting of the panels in the most efficient way, as well as to provide the best possible quality of work: Casting area :- The area where the moulds shall be placed, at a suitable height over two concrete/ brick beam.

24. Continue… Curing area :- After curing on the base plate of the mould, the panels will be transported to the curing area where they shall be kept for 14 days minimum in the curing area. The panels shall lie on four wooden/ Concrete spacer blocks (10 x 10 x 10 cm.) The size of curing area shall depend upon the daily production of panels. Stacking area :- The stacking area is well compacted to prevent uneven settlement and damages caused during transportation. The dimensions of this area shall depend upon the daily production of concrete panels. The stacking area may be divided into as many sections as there are types of panels for easy identification and transportation.   Storage sheds :- Storage sheds shall be established to store all the accessories supplied by Terre Armee like Mould accessories (steel shutters, fastening bolts etc), panel's accessories (Lifting anchors, GeoMega connectors), MSE Wall erection materials (GeoStrap5, EPDM pads, packing pads etc). GeoMega connectors and GeoStrap5 shall be store in UV protected shade. .

25. Pre start/ Tool Box meeting

26. Precasting of MSE Wall Facia Panels

27. Pre-casting of MSE Wall Facia Panels Materials :- a) Concrete & Rebars :- Concrete/Rebars should be in compliance to the contract & specification & as per approved panel reinforcement drawings. b) Connection :- GeoCore Connectors to be casted within the panel to connect the Geostrap with panel later during erection.   .

28. Continue…. Moulds :- The production of panels is based on one shift per day. Each mould has one base plate and a set of shutter ‘one-to-one’ combination of base plate and shutter. .

29. Continue…. Casting :- a) Preparation :- Prior to casting, the base & sides are cleaned so that there is no dust, concrete waste on the base. Moulds are oiled with approved quality formwork oil and excess oil is to be removed. .

30. Continue…. b) Placing of the panel accessories :- i ) GeoCore Connectors are placed in required numbers as shown in panel drawings. ii) Reinforcement as per the panel drawings is placed. .

31. Continue…. Pouring the concrete :- The concrete is poured in each unit with a minimum interruption. A needle vibrator is to be used to compact the concrete and expel the entrapped air. .

32. Handling of MSE Wall Facia Panels

33. Handling of MSE Wall facia panels Handling of facia panels a) De-moulding :- Side shutter will be removed after 6/7 hours (may be extended during winter conditions) and the panels will be lifted from the base plate after 20 hours or attaining of cube strength of minimum 10 MPA. b) Removal of the panel from the base plate :- The panel shall be lifted by mean of a four points sling using an appropriate capacity overhead gantry forklift /hydra crane. .

34. Continue…. Stacking of facia panels a) Stacking in the curing area :- The stacks of panels shall be placed on a horizontal concrete surface. The maximum number allowed is 4 (four) panels in one stack.

35. Continue…. b) Stacking in the yards :- The stacks of panels must be placed on a horizontal compacted surface. The panels can be stored in stacks less than 4 nos. .

36. Curing of Facia Panels

37. Curing of MSE Wall facia panels Curing:- The water curing shall start as soon as the concrete starts to dry. Panel may keep covered in a hessian cloth prior to handle them. The panels shall stay on the curing area for minimum of 14 days. .

38. Transportation of Facia Panels

39. Transportation of MSE Wall facia panels Transportation of facia panels Prior to their erection, the panels shall be transported and stored on site. .

40. Site Preparation

41. Site Preparation Site Preparation:- Site preparation including the works as below: a) For the length of the MSE wall section to be built, excavate the site to the depth, grade and width specified in construction drawing by removing all unsuitable material and replacing them with suitable compacted fill, if necessary. b) Level and compact the foundation in accordance with the project specifications/construction drawing. c) Mark the pad alignment on the compacted foundation layer. d) Establish formwork for leveling pad. e) Pour the concrete leveling pad. the pad should be cured for 24-72 hours (depending upon the weather condition) prior to use, or longer.   f) Insert 10mm diameter pegs in the concrete. Care to be taken while driving the pegs that finished concrete surface should not get affected.

42. Erection of MSE wall facia Panels

43. Erection of Panels 1) Snap a control line on the surface of the leveling pad using lime or marine blue. Ancillary reference points should be marked along with control line. Indicating the position of curves, corners, slip joints etc. it is desirable to mark control points on the curve at closer interval.

44. Erection and Alignement of Panels (Séquence)

45. Erection of Panels (Supports)

46. Erection of Panels (Lifting Arrangement)

47. Erection of Panels (Fixing of Geostrap )

48. Backfilling and Compaction

49. Backfilling and Compaction

50. Typical View of RE Wall After Completion

51. Site Photos 51

52. Site Photos 52

53. Thank you