Groundwater drainage and irrigation construction - general scope of works for the nursery site at. Hyde Park

Transcription

1 Groundwater drainage and irrigation construction - general scope of works for the nursery site at Hyde Park Ref. 200.D2 24 th May 2016 Shackerdale Farm Car Colston Nottinghamshire NG13 8JB +44 (0) marcus@irriplan.net.

2 Contents 1.0 Introduction 1.1 General 1.2 Drawing Register 2.0 Works 2.1 Modification of works carried out during the demolition phase, including acting upon additional findings within the demolition phase in order to achieve the full design intent Basement sump chamber to MH Works at MH Conversion of MH052 to an abstraction pumping chamber 2.3 Installation of abstraction pump and controls for transferring water to the irrigation storage tank 2.4 Irrigation storage tank 3.0 Materials specification (guidance only) 3.1 Polyethylene pipe work 3.2 Structured wall pipe (TwinWall) 3.3 Chambers 3.4 Concrete, bricks & blockwork & mortar 3.5 Backfill of chambers and of trenching Ref. 200.D2 The Royal Parks Groundwater drainage and irrigation provisional construction scope of 9

3 1.0 Introduction 1.1 General This component of the scoping for the Hyde Park Nursery Construction Package covers the following: 1. Modification of works carried out during the demolition phase, including acting upon additional findings within the demolition phase in order to achieve the full design intent 2. Conversion of MH052 to an abstraction pumping chamber 3. Installation of abstraction pump and controls for transferring water to the irrigation storage tank 4. Irrigation storage tank This document should be read and understood together with the Groundwater drainage and irrigation demolition scope of works in preparation for reconstruction of the nursery site at Hyde Park (16th May 2016). This includes any modifications to his scope necessary owing to findings within the review stage of the demolition works or afterwards. NB. Deep channels and drains are sized 6, not 8 as indicated in the above previously issued demolition package. 1.2 Drawing Register The drawings listed in italics are issued with the demolition (Phase 1) package. The drawings listed in bold are new with this document. Dwg. No. Title Size Date Rev Known Groundwater Chambers information 200.HND.01 only A New chamber for temporary pumping at the 200.HND.02 basement sump A HND.03 General basement sump chamber plan A HND.04 Inside basement sump A HND.05 Inside MH082 & MH052 A HND.06 Conversion of basement sump to gravity flow A HND.07 Conversion of MH052 to abstraction chamber A HND.05 Provisional irrigation storage tank location A Ref. 200.D2 The Royal Parks Groundwater drainage and irrigation provisional construction scope of 9

4 2.0 Works 2.1 Modification of works carried out during the demolition phase, including acting upon additional findings within the demolition phase in order to achieve the full design intent The full outcome of this part of the works is not yet known but is likely to include the following: Basement sump chamber to MH 082 A. See Dwg. No. 200.HND.06 Conversion of basement sump to gravity flow. To 2m stub of 225mm unperforated TwinWall pipe laid at approximately 17.75m, extend this pipe to location of MH082. The pipe is to be laid level or with a nominal fall. This will depend on exact levels encountered during the survey and review of the groundwater drainage system and thus is subject to change. NB: The intention is that all water that finds its way into the basement sump chamber, continues to do so, but by gravity runs towards the existing MH082 and thence to MH052 B. As an alternative to the route described above and shown on the drawing, a more direct route may be taken directly from the site of the basement sump chamber to the site of MH052, bypassing MH Works at MH082 A. MH082 (see Dwg. No. 200.HND.D.05 Inside MH082 & MH052 and Dwg. No. HND.200.D.01 Known Groundwater Chambers information only ) is known to convey water from MH051 to MH052. There is a connection between MH082 and the basement sump chamber. Its condition is dubious and there is an extensive vault / culvert beneath the top of MH082 which includes timber walling / shuttering etc.. It is proposed that this chamber be removed and a new one installed. B. The new chamber shall include a 600mm sump below the lowest invert. The lowest invert is anticipated to be the outgoing drain. However, this is not confirmed and the precise works in this area are subject to review. C. See plates 1 & 2 below Ref. 200.D2 The Royal Parks Groundwater drainage and irrigation provisional construction scope of 9

5 Plate 1: Taken from within MH082 looking south Plate 2: Taken from within MH082 looking south Ref. 200.D2 The Royal Parks Groundwater drainage and irrigation provisional construction scope of 9

6 2.2 Conversion of MH052 to an abstraction pumping chamber A. MH052 (see Dwg. No. 200.HND.1 Known groundwater chambers - information only ) is the final (known) confluence of all groundwater drainage channels at the nursery site. The current invert, upon a main channel bend, is 17.31m. It is proposed that this MH052 be completely rebuilt. B. The chamber shall be constructed of DN1500 concrete rings or as otherwise proposed by the D&B contractor) with a closed sump of 2m below the lowest pipe invert level 2.3 Installation of abstraction pump and controls for transferring water to the irrigation storage tank A. The existing pump within the newly constructed basement sump chamber shall be relocated to this new abstraction chamber. See Dwg. No. 200.HND.D.07 Conversion of MH052 to abstraction chamber B. A power supply shall be available approximately as shown on Dwg. No. 200.HND.D.06 Conversion of basement sump to gravity flow. This will have been installed as part of the Phase 1 Demolition works and is shown also on Dwg. No. 200.HND.D.03 General basement sump chamber plan C. Between the abstraction chamber (MH052) and the irrigation storage tank shall be installed a new 90mm SDR100 black PE100 rising main at c. 1m depth. D. With the rising main shall be sited 2 No. 100mm smooth-bore flexiduct suitable for carrying pump start / stop signal components and for future unspecified uses 2.4 Irrigation storage tank A. Approximately as shown on Dwg. No. 200.HND.D.8 Provisional irrigation storage tank location shall be sited the irrigation storage tank. B. This shall be a durable glass-lined steel tank (or as approved) and hold a working capacity of 150m 3. C. The tank shall be completely above ground unless as otherwise agreed D. It shall be fitted with 2 No. DN90 stainless steel risers and 1 No. DN150 stainless steel riser for incoming water (potable, groundwater, borehole) plus all other connections for level control and indication E. It shall be fitted with 1No. DN100 low level tank outlet Ref. 200.D2 The Royal Parks Groundwater drainage and irrigation provisional construction scope of 9

7 3.0 Materials specification (guidance only) 3.1 Polyethylene pipe work PE pipe work shall be as follows: Black SDR17 or 11 as described PE100 Manufactured to EN Joints: 50mm 90mm electrofusion only 110mm (Lift pump) butt-welded and reamed sticks only 110mm electrofusion 160mm electrofusion Where compression fittings are used to connect to the pump set steelwork, Plasson, Philmac or other approved manufacturer shall be used. 3.2 Structured wall pipe (TwinWall) TwinWall pipe as detailed within the tender drawings and this specification shall be a structured wall, thermoplastic, twin-extrusion pipe manufactured from High Density Polyethylene or Polypropylene. This material specification shall also apply to the Rigi-duct. Ref. 200.D2 The Royal Parks Groundwater drainage and irrigation provisional construction scope of 9

8 3.3 Chambers Precast concrete manhole chambers: made to BS EN and BS EN 1917 sized at DN1200 and DN1500. Manufacturers to be approved prior to installation. Where instructions and specifications are not given which are contrary to the Manual of Contract Documents for Highway Works Volume 1 Specification for Highway Works, Series 500, Clause 507, the Manual of Contract Documents for Highway Works shall be followed. This includes method of laying and penetrations. Concrete chambers shall be installed upon ST1 C25 concrete with a minimum depth of 200mm. Note that pre-fabricated chambers may be suitable but should be approved at tender stage. All chamber lids (including replacement lids) shall be D400. The decision on which lids might need replacement owing to age and condition shall be made by the contractor and fully costed. The necessary condition survey as part of this work may also dictate the necessity for one or more of the chambers risers, i.e. not just MH082 and MH052 to have their upper portions remade. 3.4 Concrete, bricks & blockwork & mortar Where instructions are not given which are contrary to the Sewers for Adoption 6 th Edition, Part 5 Civil Engineering Specification, the Sewers for Adoption 6 th Edition, Part 5 Civil Engineering Specification shall be followed. All concrete shall follow the specifications within the following standards: BS EN Concrete Part 1: Specification, performance, production and conformity BS Concrete Complementary British Standards to BS EN Part 1: Method for specifiying and guidance for the specifier BS Concrete - Complementary British Standards to BS EN Part 2. Specifications for constituent materials Ref. 200.D2 The Royal Parks Groundwater drainage and irrigation provisional construction scope of 9

9 The supply of ready-mix concrete shall be via a plant which is approved by a Third Party Certification Body accredited under Category 2 (Product Conformity) by the National Accreditation Council for Certification Bodies. All cement shall be sulphate resisting Portland Cement complying with the provisions of BS EN Mortar shall be mixed on site away from the Fleet Brook - as required and shall comply with the requirements of BS EN and BS EN All bricks used below ground or as part of a below ground structure shall be Class B Engineering bricks complying with the relevant provisions of BS 3921 and shall be F- Category frost resistant. 3.5 Backfill of chambers and of trenching It is anticipated that existing arisings may be used for the backfilling of trenches but the contractor shall allow for blinding if required. The minimum standards for backfilling of trenches are as included within the Specification for Highway Works Series 500 with materials complying with either Table 5/3 BS EN 13242, Coarse aggregate for pipe bedding, haunching and surrounding material, clause 4.3.2, or Table 5/4 BS EN 13242, Fine and allin aggregated for pipe bedding, haunching and surrounding material clause The fill and compaction methodology for the basement shall be provided by the structural engineers. It is anticipated that this shall include reference to Specification for Highway Works Series 600 and in particular clause Ref. 200.D2 The Royal Parks Groundwater drainage and irrigation provisional construction scope of 9

10 The Royal Parks Conversion of basement sump to gravity flow Client: Drawing Title: Project: Nursery Redevelopment Drawn By:W W Date: Scale: 1:125 Drawing No: 200.HND.D.06 The information that this drawing carries remains the property of Irriplan Ltd. This drawing is protected by copyright and may not be reproduced, copied or used for any purpose without the written consent of Irriplan. Ver. No: 1 Irrigation Drainage Water Resources Reservoirs Shackerdale Farm, Car Colston, Nottinghamshire. NG13 8JB UK This drawing shows the installation of a new 225mm unperforated TwinWall pipe to connect to a length of existing TwinWall (to be installed as part of the Demolition package) and taken to MH082. This pipe is to be laid level or, if possible with a nominal fall, and these levels are to be determined and agreed on site. MH082 is to be completely reconstructed using DN1500 sealed concrete rings above whatever base is required to enable water to be received into the chamber from the basement sump chamber, from chamber MH051 and any from any other incoming chamber/pipe by gravity. The reconstructed MH082 is to be fitted with a sump of minimum 600mm below the lowest invert. Water will be garvity fed to chamber MH052 via existing or renewed pipe work as determined at Phase 1 (Demolition). MH052 is to be completely reconstructed using DN1500 sealed concrete rings. This is to include a complete reconstruction of the bed of the chamber and all incoming drain entries and exits. See Dwg. No. 200.HND.D.07. This will become the new abstraction chamber. Notes Blue arrows show approximate route of piped groundwater.

11 The Royal Parks Conversion of MH052 to abstraction chamber Client: Drawing Title: Project: Nursery Redevelopment Drawn By:W W Date: Scale: 1:30 Drawing No: 200.HND.D.07 The information that this drawing carries remains the property of Irriplan Ltd. This drawing is protected by copyright and may not be reproduced, copied or used for any purpose without the written consent of Irriplan. Ver. No: 1 Irrigation Drainage Water Resources Reservoirs Shackerdale Farm, Car Colston, Nottinghamshire. NG13 8JB UK Notes This drawing is schematic and except for the general evelations is not to scale.all details are too be confirmed prior to construction. The pump installed within the basement sump chamber on a temporary basis for Phase 1 is to be permanantly moved to this new MH052 for Phase 2, following final clarification of distance and lift.

12 The Royal Parks Provisional irrigation storage tank location Client: Drawing Title: Project: Nursery Redevelopment Drawn By:W W Date: Scale: 1:500 Drawing No: 200.HND.D.08 The information that this drawing carries remains the property of Irriplan Ltd. This drawing is protected by copyright and may not be reproduced, copied or used for any purpose without the written consent of Irriplan. Ver. No: 1 Irrigation Drainage Water Resources Reservoirs Shackerdale Farm, Car Colston, Nottinghamshire. NG13 8JB UK Groundwater shall be collected from the Basement Sump Chamber, MH082 (which are North of MH052) and also from West of MH052. This shall all be by gravity. MH052 shall be converted to a new abstraction chamber. From this new abstraction chamber water will be pumped to a new irrigation tank. The initial suggested location of the irrigation storage tank is approximately as shown. It shall be wholly above ground and hold a working capacity of 150m³. Notes This drawing is for guidance only for tendering and is not for construction.