Temporary & Permanent Anchorage Designs in Working Excavations All Diameters up to 2 bar

Transcription

1 Temporary & Permanent Anchorage Designs in Working Excavations All Diameters up to 2 bar triio l QFM311 Remember it is for YOUR Safety! Issue 2 February 2018 Safety starts with Me This document is solely for use by employees working on triio that are competent to approve and install herein designs. If you require any further assistance please contact a TWC. 1 of 42

2 Limitations that apply to the Standard Anchorage Designs: The following notes and assumptions apply to all designs in this booklet. If any of these ceases to be applicable, do not use this booklet and instead contact a TWC. 1. All anchorage on LP mains up to and including 12 diameter should use an AVK selfanchoring end caps. Refer to EB202 for further info. 2. Temporary restraint shall be provided to prevent pipework movement, or fittings being dislodged, during cut out operations or flow stopping; 3. There is no ground water present i.e. water flowing into the excavation; 4. The ground conditions meet the Good / Poor conditions described herein; 5. There are no discontinuities or changes to the line and level of the trench; 6. Minimum timber grade to be C24 in accordance with BS 338 and to the sizes specified; 7. Steel adjustable trench struts to be in accordance with BS 4074:2000; 8. Timber transverse restraint maximum length 3.5m; 9. Adjustable steel Acrow props are not to be used. Adjustable steel trench struts are allowed; 10. Any shuttering should be of plywood or sheet metal and firmly located to withstand poured concrete. For concrete formwork design contact TWC; 11. Concrete Compressive Strength Class to be C40/50 in accordance with BS :2006+A1:2012 Concrete. Complementary British Standard to BS EN and shall conform to :2006+A1:2012. Refer to specification GEN-SPC-001 (last page) for details; 12. A cure time of at least 24 hours should be allowed before loads are applied to the concrete anchor; 13. Concrete to be protected from sun and wind and covered with either a damp absorbent material or a well-sealed and fastened polyethylene sheet immediately after pouring; 14. Good contact between the pipe and its restraint must be maintained; 15. For base roughness prior to concrete pour, brush base with a bristle broom. The bottom of any excavation is to be clean and free from debris before casting any concrete upon it; 16. Legal, safety and environmental requirements to be met in full; 17. Any loads or diameters outside the scope of this document refer to TWC; 18. Refer to Page 3 for ground conditions identification; excavations to comply with QFM309 Issue 2.0 and 19. To conform with manual handling legislation please refer to table below: Note: 225 x 75mm = 9 x 3 (weighs 8kg/m length) 250 x 100mm = 10 x 4 (weighs 11kg/m length) 300 x 150mm = 12 x 6 (weighs 22kg/m length) Anchorage designs shall be detailed within the RO / NRO Method Statement. An inspection as per triio BN133 shall verify that adequate restraint is provided and should take into account the potential for ground movement. Temporary restraint systems shall be inspected on a regular basis by the TWS to ensure that the integrity of the restraint is maintained. The frequency of inspection will vary depending on local circumstances such as pressure, size and location but will be at a maximum of 7 day intervals. Additional visual inspections shall be carried out by site operatives at the beginning of morning and afternoon shifts. Any change should be immediately reported to the TWC/TWS. Please note that restraint during flow stopping/cut out operations should form a threetrench system of working whenever possible. This document details temporary and permanent anchorage to be used in a single trench system of operation. 2 of 42

3 Ground Conditions Soil Type Conditions Field Identification Granular material, such as gravels and sands where stability is Non-cohesive Soils dependent on the shape and size, the variety of particle size (grading) and the state of compaction. Where soils are pure sand or gravel and of a single size, stability is poor. Granular Soils Cohesive Soils Clays Permeable soils which require a system of support capable of preventing fine particles washing out from the surrounding soils. This places a greater force on the timbering if the water cannot be released through sheeting joints. Loose gravel/sand can be excavated by spade; 50mm peg driven easily. Dense gravel/sand requires pick to excavate; 50mm peg hard to drive. Have plasticity (capacity for being moulded) and are subject to volume changes (shrink or swell) with changes in moisture content. Usually a mixture of clay, silt and Very Soft - Extrudes between granular particles. The moisture fingers when squeezed. content determines whether they are soft, firm or stiff. Clays are fairly Soft - Moulded by light finger impermeable (water-resistant) and pressure. provide no water unless heavily infused, or there are underlying Firm - Moulded by strong unstable beds of water-bearing sand finger pressure. or gravel. Stiff - Cannot be moulded, Indent by thumb. Silts Plasticity (capacity of being moulded) varies depending on the moisture content so silts are treated as fine compact sand during excavation. Peat Made Ground Organic material varying from fairly stiff to loose easily crumbled wet material. Peat is comparable with soft clay for stability. Soil that has not occurred naturally and can vary from tipped refuse/soil to good compacted granular fill. Very Stiff - Indented by thumb nail. Soft Loose Easily moulded or crushed in fingers. Firm/Dense Can be moulded or crushed by strong pressure in fingers. Firm Fibres compressed together. Plastic Can be moulded in hand and smears on fingers. When excavating made ground, approach with caution and always treat as unstable material and contact a TWC. 3 of 42

4 Index of Designs DESIGN DESCRIPTION PAGE No. Design A1 Temporary Transverse Beam 300mm Wide Embedment into 5 Trench Sides Design A2 Temporary Transverse Beam 500mm Wide Embedment into 7 Trench Sides Design A3 Temporary or Permanent Concrete End Cap Anchorage 9 Design A4 Temporary Longitudinal Strut Central to Excavation 11 Design A5 Temporary Double Longitudinal Strut with Transverse Beam 13 Design A6 Timber Longitudinal Struts at Various Lengths between Cap 16 Ends Design A7 Single Steel Longitudinal Struts at Various Lengths between 17 Cap Ends Design A8 Temporary (Steel Trench Struts) & Permanent (Concrete Block) 18 Anchorage Design A9 Temporary Valve to Cap Anchorage Using Timber Packing 19 Single 9 X 3 Design A10 Temporary Cap to Cap Anchorage Using Timber Packing 20 Single 9 X3 Design A11 Permanent Concrete Anchorage of Mechanical Stopple Tees in 21 a Single Excavation Design A12 Ground Between Excavations (Temporary) 24 Design A13 Temporary or Permanent Concrete Anchorage to Pipe Bends 26 at Angled Trench Corners Design A14 Precast Concrete Temporary Anchor Blocks Against Cap End 28 Design A15 Tapping Tees Embedded in Concrete Anchorage 29 Design A16 Steel Anchor Plate & Electrofusion Coupler 31 Design A17 Restraining Clamp with Tied Flange Adapter or End Cap 34 Design A18 END CAP RESTRAINTS - Georg Fischer 37 Design A19 END CAP RESTRAINTS - Viking Johnson 38 Design A20 END CAP RESTRAINTS - AVK 39 Design A21 Temporary or Permanent Concrete Block (800mm Deep) & 40 Concrete Specification Cantilevered Posts Anchorage Concrete Specification GEN-SPC of 42

5 TEMPORARY TRANSVERSE BEAM 300mm wide embedment into trench sides Design A1 Transverse beam to be restrained so as to prevent lateral or vertical movement Trench to be shored (wood or steel shoring) in accordance with triio Trench Design Booklet adjacent to the transverse beam for a length which is a least 800mm. For transverse beam size refer to Table 1 Wooden packing (ideally 19mm plywood) to be of larger face area than the end cap diameter. Pressurised system 5 of 42

6 Table 1: Transverse Beam Sizes - 300mm wide embedment into trench sides Maximum trench width 2.5m 6 of 42

7 TEMPORARY TRANSVERSE BEAM 500mm wide embedment into trench sides Design A2 Transverse beam to be restrained so as to prevent lateral or vertical movement Trench to be shored (wood or steel shoring) in accordance with triio Trench Design Booklet adjacent to the transverse beam for a length which is at least 800mm For transverse beam size refer to Table 2 Pressurised system Wooden packing (ideally 19mm plywood) to be of larger face area than the end cap diameter 7 of 42

8 Table 2: Transverse Beam Sizes - 500mm wide embedment into trench sides Maximum trench width 2.5m 8 of 42

9 TEMPORARY OR PERMANENT CONCRETE END CAP ANCHORAGE Design A3 Timber (ideally 19mm plywood) or steel packing to be used between concrete and end cap if required. Ensure packing to be of a larger face area than the end cap diameter. L Concrete specification refer to GEN- SPC-001. Concrete width never to be less than trench width. For concrete dimensions refer to Tables 3 & 4. H Pressurised System 9 of 42

10 CONCRETE END CAP DIMENSIONS The trench bottom should be firm but rough enough to maximise shear resistance, and the sides should be cut back to firm, undisturbed ground with a plane vertical surface perpendicular to the direction of the applied load. WIDTH OF CONCRETE SHALL BE NEVER LESS THAN TRENCH WIDTH Table 3: End Cap Concrete Anchorage Good Ground Table 4: End Cap Concrete Anchorage Poor Ground 10 of 42

11 TEMPORARY LONGITUDINAL STRUT Central to Excavation Steel trench sheets supporting excavation in accordance with Trench Support Designs QFM309 Note: Walers and side excavation support has been omitted for clarity. Design A4 Timber wedges to be used as packing to ensure a good connection between the trench sheets and anchorage waler. Anchorage waler to be 1 No. 9 x 3 C24 timber and span the width of the excavation Strut to be C24 longitudinal timber or adjustable steel trench struts. Multiple timber struts to be connected using 2.8mm diameter x 100mm long screw nails at 300mm centres top and bottom. For timber strut sizes refer to Table 5. C24 timber off-cuts used to support longitudinal strut Timber (ideally 19mm plywood) or steel packing to be used between strut and end cap if required. Ensure packing to be of a larger face area than the end cap diameter. Notes: 1. Ensure longitudinal strut is level both vertically and horizontally using a spirit level; and 2. Timber or steel packing to be used at both ends of strut. 11 of 42

12 Table 5: Maximum Mains Diameters for Single Longitudinal Strut between Cap End to End of Trench at Various Widths 3.5m Maximum Strut Length. Steel Trench Strut Length to suit site conditions. 12 of 42

13 Steel trench sheets supporting excavation in accordance with Trench Support Designs QFM309 TEMPORARY DOUBLE LONGITUDINAL STRUT With Transverse Beam Note: Walers and side excavation support has been omitted for clarity Design A5 Anchorage waler either side of the main C24 timber off-cuts used to support longitudinal strut See Table 7 for C24 transverse beam Struts to be either C24 9 x 3 longitudinal timber or adjustable steel trench struts Timber (ideally 19mm plywood) packing to be larger face area than the end cap diameter. Pressurised system Notes: 1. Ensure longitudinal struts are level both vertically and horizontally using a spirit level; 2. Timber or steel packing to be used at both ends of strut; 3. For strut sizes refer to Table 6. For transverse beam sizes refer to Table 7; and 4. Table 5 governs maximum mains diameters allowed for applicable trench depths and widths. 13 of 42

14 Table 6: Maximum Mains Diameters for Double Longitudinal Struts between Cap End to End of Trench at Various Widths 3.5m Maximum Strut Length. Steel Trench Strut Length to suit site conditions. 14 of 42

15 Table 7: Maximum Mains Diameters for Transverse Beams being used in a Double Longitudinal Strut Arrangement 15 of 42

16 Table 8: Maximum Mains Diameters for Timber Longitudinal Struts at Various Lengths between Cap Ends Ensure all struts are horizontal (level) using a spirit level during installation and suitably supported using off-cuts. Struts to be checked at start of each shift. Design A6 16 of 42

17 Table 9: Maximum Mains Diameters for Single Steel Longitudinal Struts at Various Lengths between Cap Ends Ensure all struts are horizontal (level) using a spirit level during installation. Struts to be checked at start of each shift. Packing at end caps to be larger than face area of gas main. Packing to be 19mm plywood. Table 10: Maximum and Minimum Lengths of Steel Trench Struts to BS 4074:2000 Design A7 17 of 42

18 TEMPORARY (STEEL TRENCH STRUTS) & PERMANENT (CONCRETE BLOCK) ANCHORAGE Suitable for all size diameters up to 2bar pressure. Design A8 18 of 42

19 TEMPORARY VALVE TO CAP ANCHORAGE USING TIMBER PACKING SINGLE 9 X 3 Suitable for all size diameters up to 2bar pressure. Design can also be used to temporary anchor valve against flange adapter. Design A9 19 of 42

20 TEMPORARY CAP TO CAP ANCHORAGE USING TIMBER PACKING SINGLE 9 X3 Suitable for all size diameters up to & 2bar pressure. Design A10 20 of 42

21 PERMANENT CONCRETE ANCHORAGE OF MECHANICAL STOPPLE TEES IN A SINGLE EXCAVATION For a three trench system follow Clause T/PM/MSL/1 WIDTH OF CONCRETE SHALL BE NEVER LESS THAN TRENCH WIDTH Design A11 21 of 42

22 STOPPLE CONCRETE DIMENSIONS Table 11: Anchorage of Mechanical Stopple Tees Good Ground Ensure there is a minimum of 300mm between the excavation base to the underside of the main 22 of 42

23 Table 12: Anchorage of Mechanical Stopple Tees Poor Ground Ensure there is a minimum of 300mm between the excavation base to the underside of the main 23 of 42

24 GROUND BETWEEN EXCAVATIONS (TEMPORARY) The length of undisturbed ground obtained from Tables 13 to 16 will fully accommodate and resist the forces imposed on the mains isolation device to ensure no pipe movement when the pipe is cut and gapped as part of a three trench system. Table 13: Ground between Excavations Good Ground & 0.6m Cover Table 14: Ground between Excavations Good Ground & 0.9m Cover 24 of 42

25 GROUND BETWEEN EXCAVATIONS (TEMPORARY) Table 15: Ground between Excavations Poor Ground & 0.6m Cover Table 16: Ground between Excavations Poor Ground & 0.9m Cover Note: Tables 13 to 16 can also be used to determine the amount of undisturbed ground to be left in place on a low pressure system where a non-anchored mains joint is exposed within the excavation. Seek advice from a TWC for further info. 25 of 42

26 TEMPORARY OR PERMANENT CONCRETE ANCHORAGE TO PIPE BENDS AT ANGLED TRENCH CORNERS Design A13 Note: Concrete Specification refer to GEN-SPC of 42

27 Table 17: Concrete Dimensions at Angled Trench Corners Good Ground Table 18: Concrete Dimensions at Angled Trench Corners Poor Ground 27 of 42

28 PRECAST CONCRETE TEMPORARY ANCHOR BLOCKS AGAINST CAP END Design A14 NB: Block to be located with the longest dimension running perpendicular to main. Table 19: Maximum Main diameters for Legato Concrete Anchorage 28 of 42

29 TAPPING TEES EMBEDDED IN CONCRETE ANCHORAGE Design A15 Note: Concrete Specification refer to GEN-SPC-001 Ensure tees are located centre of concrete block 29 of 42

30 Table 20: Minimum No. of 32mm Tapping Tees Embedded in Concrete Anchorage Table 21: Minimum No. of 63mm Tapping Tees Embedded in Concrete Anchorage Note: Ensure tee spacing (min. 50mm) is complied with as per page 234 T/PR/ML/4. For SDR 26 pipes and all swage lined pipes, contact a TWC. 30 of 42

31 Steel Anchor Plate & Electrofusion Coupler Max distance between PE fused coupler and existing metallic connection to be max. 1.5m, if length is greater seek advice from a TWC. As host main acts as restraint ensure there is sufficient length of undisturbed ground behind to allow no movement (refer to Tables 13 to 16). Design A16 31 of 42

32 32 of 42

33 Table 22: Steel Ring Thickness and Diameters 33 of 42

34 Restraining Clamp with Tied Flange Adapter or End Cap Notify a TWC prior to use. Suitable for all size diameters up to 350mb pressure. If clamp is embedded in concrete suitable up to 2bar Design A17 34 of 42

35 35 of 42

36 36 of 42

37 SELF ANCHORING END CAP RESTRAINTS Notify a TWC prior to use. Georg Fischer MULTI/JOINT 3207 Plus Wide Range end-cap blind, restraint, Uni/Fiksers Suitable for all size diameters up to 2bar pressure. Suitable for all kinds of pipe material. Design A18 37 of 42

38 SELF ANCHORING END CAP RESTRAINTS Notify a TWC prior to use. Viking Johnson Ultra Grip End Cap Suitable for all size diameters up to 2bar pressure. Suitable for all kinds of pipe material. Design A19 38 of 42

39 SELF ANCHORING END CAP RESTRAINTS Notify a TWC prior to use. AVK SupaMaxi End Cap Suitable for all size diameters up to 2bar pressure. Suitable for all kinds of pipe material. Design A20 39 of 42

40 TEMPORARY OR PERMANENT CONCRETE BLOCK (800mm Deep) & CANTILEVERED POSTS ANCHORAGE Notify a TWC prior to use. Design A21 40 of 42

41 TEMPORARY OR PERMANENT CONCRETE BLOCK (800mm Deep) & CANTILEVERED POSTS ANCHORAGE Notify a TWC prior to use. 41 of 42

42 GEN-SPC-001 CONCRETE SPECIFICATION to BS EN Part 1 Designation C40/50 Compressive Strength Slump Class 50N/mm² S3 Max W/C Ratio 0.45 Min. Cement Content Max. Aggregate Size 340kg/m³ 20mm Concrete to cure for min 24hrs prior to any loading 42 of 42